Baseline Study - Soil - Bequia. N. Ahmad by Richmond Vale Academy

Base-line study on the soils of St. Vincent and the Grenadines (Bequia) with emphasis on maintenance of productivity Contents Page no. 1

Rationale, terms of reference and presentation of reports

Part I: Soils investigations carried out in St. Vincent prior to 2003.

Part II: Capability, fertility status, recommended land use and soil

fertility maintenance. 3.1

St. Vincent soils

3.1.1

Introduction

3.1.2

Identification and sampling of St. Vincent soils

3.1.3

Sample preparation and arrangements for analysis of St.

Vincent soils 3.2 4

Bequia soils The agro-ecological environment of St. Vincent and Bequia

5 5

4.1

St. Vincent

4.2

Bequia

5.0

Land capability studies in St. Vincent and Bequia

5.1

St. Vincent

5.1.1 Previous land capability/land use studies in St. Vincent

5.2

Bequia

6.0

Soil analysis and interpretation of results

6.1

Methods and interpretations

6.2

Conversions

7.0

Land capability, fertility assessment, land use recommendations

and fertility maintenance. 7.1

Soils of St. Vincent

1.2

Greggs

3.6

Montreal

Lettswood

8.9

7.2

St. Vincent

Westwood

Claxton

Kings

Fort

14-16 Akers

Penniston

18-21 Bellevue

22-23 Gabriel

24-25 Belmont

26-27 Myrtle

28-32 Soufriere

Chaufleur

Ferret

Diamond

Yambu

Garden sandy loam

Garden loam

Greathead

40-41 York

Still

101

43-44 Colonarie

103

Richmond

107

Brighton

109

Beach sand

111

Soils of Bequia

112

113

Camel

Mount pleasant clay

114

Union level clay

116

Cinnamon garden clay

117 ii

Friendship clay

118

Paget farm clay

120

Spring

121

8.0

Conclusions

125

9.0

Literature cited

127

iii

1.0

Rationale, terms of reference and presentation of reports

This study was initiated by the Government of St. Vincent and the Grenadines through the service of Professor Nazeer Ahmad, Emeritus Professor of Soil Science at the University of the West Indies, St. Augustine, Trinidad. This initiative was taken on the realization that: (i) The last comprehensive soil analysis done on the soils of St. Vincent was in the 1950â&#x20AC;&#x2122;s in support of the soil survey of Watson et al. (1958). (ii) The analytical methods and procedures used in that study have been discontinued for a long time and the interpretation of the data which was incomplete is now problematic. (iii) Since then, the banana crop became established island-wide and in quest of high yields, increasing rates of fertilizers were applied. There was little research support to establish the various nutrient compositions of the fertilizers presently in use and in any event there is no longer a regional research organization such as WINBAN to conduct studies. Other crops also received increasing amounts of fertilizers regardless of soil conditions. (iv) Inspite of the levels of the fertilizers being used, yields of banana are difficult to maintain. (v) In the present situation, it is not known to what extent the fertility status of the soils might have changed due to residual effects but also to continued soil loss through soil erosion processes. (vi) Due to a problematic future for banana marketing, it is strongly felt nationally that agricultural diversification should be more actively pursued and in this regard, special emphasis is being given to the rehabilitation of the arrowroot industry. The Agricultural Diversification Programme Implementation Unit (ADPIU) within the Ministry of Agriculture and Fisheries was created to support this policy of diversification. (vii) The view is presently strongly held within the Ministry that it is now appropriate to have a re-appraisal made of the current fertility status of the soils of the island using up to date methods of analysis and technology with guidelines to support agricultural diversification. (viii) The decision was also made to include the soils of Bequia in this study.

The following are the agreed Terms of Reference for the study: The Contractor shall perform the following services: (i) Create a comprehensive collection of relevant literature on soils and their use of St. Vincent and the Grenadines. (ii) Review all previous work on soil management with emphasis on soil fertility maintenance. (iii) The report should consist of the following areas: a. A review of all studies listed in chronological order. b. A summary of all findings for each study. c. Produce a critique of all previous work indicating areas of weaknesses and deficiencies. (iv) Plan and execute a strategic sampling of the main agricultural soils within the framework of the agro-ecological zones and submit soil samples for analysis for fertility assessment to a suitable laboratory either in Florida or the Dominican Republic. (v) On the basis of the report referred to above and on the results of soil analysis to be carried out, recommend a plan of action to improve soil management with specific reference to soil fertilizer formulation for use on all soils and crops and to recommend other improved soil management practices for sustained land use. It is conceived that this study comprises two parts although closely related. Part I is described by the Terms of Reference I to III. For the purposes of reporting, Part I is entitled “Soils Investigations carried out in St. Vincent and the Grenadines prior to 2003”. Part II which is described in Terms of Reference IV and V is entitled “Fertility, productivity and recommended use of the soils of St. Vincent and the Grenadines”. 2.0

Soils investigations carried out in St. Vincent and the Grenadines prior to 2003 (See separate Report)

3.0

Part II

3.1

St. Vincent

Capability, fertility status, recommended land use and soil fertility maintenance of the soils of St. Vincent and the Grenadines (Bequia)

3.1.1 Introduction: As indicated in the Terms of Reference, this part of the study involved a strategic sampling of the soils of the country and to have the samples analysed to assess their current fertility status. On the basis of the analytical results and other observations made in the field, recommendations would be made to improve soil management with specific reference to soil fertilizer formulations for use on all

soils and crops; other management practices to attain sustainable land use would also be made. Instead of the main agricultural soils that was outlined for study in the Terms of Reference, all the soils of the St. Vincent and Bequia were included except the skeletal soil of the islands. 3.1.2 Identification and sampling of soils: For St. Vincent, the mapping and soil descriptions of Watson et al (1958) was used as a guide. In this work, the soils were mapped at 1:20,000 scale with incomplete but fair descriptions. From previous experience working with this Report, it was found that the soil boundaries are good and indicate a true pattern of distribution of the various soils. However, the soils were mapped on an old topographic base map which is no longer in use. Further, there is only limited topographic information given on the map such as roads, rivers, and place names and especially the roads as indicated, are misleading. Public facilities such as schools, hospitals, cemeteries, banana packing sheds etc. are not given. These deficiencies made it quite difficult to identify precise locations on the existing soil map. This process was greatly aided by using a modern topographic map on a scale of 1:25,000 in conjunction with the soil map to obtain accurate locations. In principle, when identifying a soil for sampling, a fairly large occurrence of the soil was identified on the soil map to which there was access either by vehicle or by walking. The colour, texture, structure and other site characteristics were then compared with the information on that soil given by Watson et al (1958) and from personal experience. If the field and recorded information did not agree, another site was similarly selected and the soil checked. Only when it was certain that the soil in the field corresponded to that described by Watson et al (1958), was the soil sampled. An Edelman soil auger (6.5cm) for clay soils was used to examine and sample the soils; about one kilogramme of soil in field condition was taken for each sample. The actual sites selected for sampling were either cropped with banana, being the most common usage, in food crops, in fallow, abandoned or in natural pasture. Where crops were growing care was taken not to take samples too close to the growing crop to avoid areas of concentration of applied fertilizers. Samples were taken from three depths – usually 0 – 15, 15 – 30 and 30 – 60cm. Especially for the surface sample (0 – 15cm), on the average sub-samples were taken from at least four sites and mixed. The samples were put in polyethylene bags and transported to a small laboratory at Camden Park where further processing was done. Identification and sampling of the soils were started in the north of the island around Fancy and continued southwards along the east side and around the south and along the east. Interior areas such as Montreal, Vermont, Buccament and

Rosehall were reached through secondary roads and foot-paths along river courses. For a few of the major soils which occur in different ecological zones, samples were taken from two sites but generally, one set of samples were taken for each soil. Altogether, 163 soil samples were taken and the complete process took 17 working days. 3.1.3 Sample preparation and arrangements for analysis: The samples were brought to a Laboratory at the Bureau of Standards Building in Camden Park where each sample was spread out on a bench on paper. The clods were broken by hand which was not difficult since the soils were mainly friable. The total volume of soil in the sample was then thoroughly mixed by hand and in the process, any coarse material such as small stones were removed and discarded. About 250g of the sample was then placed in double lined plastic bags for shipment to A and L Agricultural Laboratories, Pompano Beach, Florida with which previous arrangements were made for the analysis to be done. The remainder of each sample was replaced in plastic bags for storage and safekeeping in St. Vincent for reference purposes. It was agreed that the following determinations would be made: soil pH, organic matter content, estimated nitrogen release, cation exchange capacity and exchangeable calcium, magnesium and potassium and available phosphorus (Bray P1) and the stronger acid extraction (Bray P 2). It was strongly felt that the opportunity should be taken at this time to present all the useful available information on the soils particularly their use and management in the context of how these features can be influenced by the results from the soil analysis. Accordingly, each soil was considered under the following heads: • General description of the soil including the slope classes, steepness of slope (degrees), the land area for each slope class and the corresponding land capability rating; also presented in this section are the soil name, classification and rainfall regime which is characteristic of the soil. • Current land use and features of the site sampled: in this section, details of the sampling such as sample number, depth of sample and any special comments about the soil and site are given. • Soil fertility assessment: The assessments were made based on the results of the soil analysis which was carried out as part of the study. • Land use recommendations: This recommendations were based on the environmental factors and results of the soil analysis.

â&#x20AC;˘

3.2

Soil fertility maintenance: The recommendations were based on the current fertility status of the soils, the types of fertilizers which are commonly available and recommended crops.

Bequia Soils:

The same procedures as described above for soil identification and sampling and sample preparation and analysis for St. Vincent, was followed for Bequia (area of 18.5 km2) except that the soil survey report and soil map of Bequia (Ahmad, 1987) were used as guide. In presenting the data and information on the various soils, the same format as for St. Vincent was used except that recommended land use and soil fertility management for all the soils are presented in one section. This was justified on the close resemblance of the soils, lack of history of agricultural use and uniform agro-ecological conditions affecting all the soils equally on Bequia. 4.0

The agro-ecological environment in St. Vincent and Bequia

4.1

St. Vincent

The agricultural environment of St. Vincent consist largely of the soils of the country and its climate, particularly the annual rainfall and its distribution. These two factors together determine the types of crops and crop combinations which are possible. The important aspect in this regard is the length of the rainy season, the number of dry months (months in which less than 100mm of rainfall is received) and the amount of rainfall which is actually received during the dry months. The length and intensity of the dry season has resulted in its classification as continuously moist, weak, marked and intense. These are the factors which are important in determining the agro-ecological zones or ecozones in St. Vincent. The use of irrigation, if possible, by meeting the water deficit during the dry months, can ameliorate this environment/crop relationship. This is very evident in very dry areas such as Israel and other Middle-East countries where, with irrigation, almost any crop can be grown. In this report, special attention is given to the soils of St. Vincent and Bequia, especially their fertility status, recommended land use and soil fertility maintenance. It is however, important to give some attention to the climatic factor and how this is related to the distribution of the soils and their use. On St. Vincent annual rainfall ranges from about 3750 mm in the central mountains to as low as 1500mm near the coast. This distribution superimposed on the basic shape of the island has resulted in a zonation of rainfall in concentric belts around the central mountain core. The highest mountains are the wettest areas. Unlike

the other windward islands, the western part of St. Vincent is mountainous with steep slopes and the gentler, longer slopes are on the eastern size. Thus the western or leeward side of the island receives more rainfall than the windward or eastern side. In Figure 1, the rainfall distribution emphasizing its zonation around the island is presented. The number of dry months (less than 100mm precipitation) is used as the main factor along with the annual rainfall in demarcating the agro-ecological zones or ecozones. It is expected that in a small tropical island like St. Vincent where other environmental factors are more or less uniform such as vegetation, soil parent material, time and relief, it is the intensity and distribution of rainfall that will more profoundly influence soil formation. The various soil groups associated with the different rainfall regimes are indicted in Fig. 1 and the number of dry months are given in each case. Watson et al (1958) suggested the significance of the length of the dry periods in terms of soil water; with rainfall over 2,500 mm per annum with no dry months, the soil remains moist throughout, with annual rainfall of 2175 to 2500 mm and one dry month, the top-soil dries out, with annual rainfall of 1725-2175 mm and 2 â&#x20AC;&#x201C; 3 dry months and a marked dry season, the topsoil and sub-soil dry out and with annual rainfall of less than 1725mm with 4 â&#x20AC;&#x201C; 6 dry months and an intensive dry season, the top soil and subsoil will dry out. Unless irrigation is available, these soil moisture regimes will determine what crops can be produced in the respective zones.

Figure 1:

Map of St. Vincent showing the agro-ecological zones (eco-zones) and associated main soil groups ( Adapted from information made available by Mr. A. Cain)

ECOZONE

Rainfall (mm) No. of Dry Months Altitude (m) Soils

III

<2125

1725-2125

2-3

2125-2500

<2125

>2500

3-6

2-4

>200

<200

>200

<66

>330

High Level Yellow Earth

Recent Volcanic Ash Soils

Alluvial Soil

High Level Yellow Earth

2175-2500

<2125

2-3

<100

<100 <200

Shoals

Low Level Yellow Earth

Based on natural conditions the following crops are suited to the various ecozones: Ecozone I

Rainfall (mm) <2125

Dry months 2–3

1725-2175

2–3

III

2125 – 2500

IVa

<2175

3-6

IVb

2125-2500

<2125

2-4

Recommended crops Aroids, sweet potato, short term food and vegetable crops. Aroids, sweet potato, other root crops, perennial crops. Banana, root crops, arrowroot, selected perennials Arrowroot, selected food and vegetable crops and selected perennial crops Banana, some root crops, selected perennial crops Vegetable crops, food crops, melons

This list is not exhaustive and it is subject to change as experience is gained. The most significant seasonal climatic change in St. Vincent is the migration of the inter-tropical convergence zone (ITCZ) with the seasons. From January to June the north-east trade winds predominate as tropical air moves towards the ITCZ – at that time to the south. The constant north-east trades make this time of the year very pleasant but crops on the eastern side can suffer from leaf scorch caused by sea blast. From May until November as the ITCZ moves to its northernmost position over the Caribbean, rainfall is heaviest and some 70 percent of the total rainfall is usually received. Thunderstorms are fairly frequent and some damage to crops occur but the good water supply makes this time of the year the main crop growing season. Although St. Vincent lies within the hurricane belt it seldom suffers hurricane damage. The traditional crops of St. Vincent which are not necessarily important today such as cotton and sugarcane which require particular climatic conditions for their various agronomic stages were naturally distributed throughout the island to fit into the suitable ecological niches. Those crops which require shelter such as cotton, cacao, banana and plantain could not be grown in exposed areas. Arrowroot, coconut, peanut, most root crops and sugarcane are tolerant of windy sites so over-exposure was not an important factor in their distribution. Rather, the amount of rainfall and the way it was received were more important. The flat, low-lying alluvial soils, because of the effect of elevation, usually have 2 – 4 dry months and this traditionally limited the selection of crops in these locations to sugarcane, pasture and vegetables. 8

With the advent of irrigation, the disappearance of some of the traditional crops such as cotton and sugarcane, the pre-eminent importance of banana and the very widespread production of aroids and arrowroot, there is now more tendency to create environmental conditions which are suited to particular crops. In this regard, certain tendencies could be of importance such as lack of attention to the establishment and maintenance of windbreaks, clearing of mountainous land which lead to increase in run-off and eventually decreased availability of soil water at lower elevations and scant regard for soil conservation can all lead to a new level of environmental degradation which will be detrimental to crop production. It is important to be aware of these possibilities. Since the individual soils are associated with the various ecozones in their occurrence and distribution, in recommending land use and soil fertility maintenance practices for each of them, the specific agro-ecological conditions are integrated in the recommendations. However, these recommendations must be considered in a dynamic sense as new crops and technologies for their production are introduced. 4.2

Bequia

Bequia can be put in one ecozone. Limited climatic data is available and in addition to low annual rainfall, there is an erratic distribution. The average rainfall received is about 1700mm; the amount and its distribution are characteristic of the â&#x20AC;&#x153;dry beltâ&#x20AC;? of the Caribbean as described by Marshall (1932). The maximum annual rainfall received in this belt is about 1651mm which would put Bequia just outside. However, the distribution of the rainfall is very much typical of this belt, there being a dry period of five months (January to May) during which the average monthly rainfall is well below 100mm, which is the amount needed for evapotranspiration. The erratic nature of the rainfall is illustrated by the fact that the annual range from available data is about 1040mm to 2250mm. The evaporation in the dry months is increased by the strong winds and long hours of sunshine received during this period. The main effect of the climate on the vegetation is drought with the climax vegetation being deciduous seasonal to dry evergreen forest (Beard, 1949). On Bequia the woodlands have been largely cut over and the present vegetation is dominated by Acacia spp., birch gum ( Busera simaruba) and white cedar ( Tabebuia pallida). The vegetation is scant and the soils are shallow and youthful. Without irrigation, intensive agriculture is severely constrained and require maximum moisture conservation, precise scheduling of cropping operations and careful selection of crops.

5.0

Land capability studies in St. Vincent and Bequia

5.1

St. Vincent

A general system of land capability classification was formally proposed by the USDA (Klingebiel and Montgomery, 1966) mainly to classify land for suitability for mechanized agriculture. Differentiation between these classes is based on those particular characteristics and qualities of site and soil that limit land utilization or impose significant restrictions when the land is being used for modern mechanized agricultural production. Within a class is grouped soils that have the same restrictions, limitations or hazards to agricultural utilization under any given kind, system or level of land management. Land having the largest number of alternative uses under a given system of management is placed in Class I and land with the least number is placed in Class VIII. Therefore, the number of restrictions, limitations or hazards to agricultural utilization increases progressively from Classes I â&#x20AC;&#x201C; VIII. In general, land grouped in Classes I to IV inclusive is regarded as suitable for mechanical tillage, although, it would also be suitable for growing tree crops or timber if necessary. Land belonging to other Classes is considered to be unsuitable for mechanical agriculture and capable only of growing pasture crops, tree crops and forest or as used throughout the Caribbean for manual cultivation of food crops. The following summarises in simplest terms the essential feature of each land capability class: Class I Suitable for cultivation (tillage) with no limitations. Class II Suitable for cultivation (tillage) with moderate limitations. Class III Suitable for cultivation (tillage) with strong limitations or intensive practices. Class IV Suitable for cultivation (tillage) only with special practices, though best suited to growing pasture grasses and tree crops. Class V Not suitable or only marginally so for cultivation (tillage) but suitable for growing of pasture crops, orchard crops or forest. Class VI Not suitable for cultivation but suitable for poor pasture and forest. Class VII Not suitable for cultivation (tillage); suitable only for rough pasture, wild life, recreation and water conservation. Class VIII Soils and land forms with limitations that preclude their use for commercial plant production and restrict it to recreation, wildlife preservation, water supply or for esthetic purposes. Any one of the site and soil characteristics and qualities can constitute a restriction, limitation or hazard to crop growth and production if it is not operating at or near its highest efficiency. These characteristics are given Sub-Class status and each is assigned an appropriate index letter which is inscribed on land

capability maps. follows:

The index letters with the corresponding limitations are as

Restriction, Limitation Or hazard Climate Relief, erosion Excessive wetness or dryness Soil characteristics i.e. Salinity hazard, impediments to root growth etc.

Index Letter c e w s

For example, land capability Class Ve indicates that the land is just marginal for cultivation (tillage, that the principal limiting factor is severe erosion, but climate or some soil factor such as stoniness may further limit the agricultural use of the soil, thus justifying its grouping in Class V. Since the classification is intended to grade land for suitability for mechanized agriculture, slope or relief of the landscape is of prime importance. Therefore, in developing countries where mechanized agriculture is not advanced, strict adherence to the system could lead to some anomalous situations. For example, in cacao cultivation, soils highly suited to this crop on slopes would have a much lower rating than if they were being considered specifically for cacao cultivation. Similarly, flat land with no relief which may be highly suited for rice cultivation would be placed in a much lower category for general suitability for agriculture due to implied difficulties in drainage as a result of the relief. In the Caribbean, very steep land (>20 0 slopes) is used throughout for manual cultivation of food crops, many of the holdings being on a permanent basis, although shifting or rotational cultivation is also practised. In such areas, considerable expertise sometimes exist among farmers in managing such steep areas. The farmers involved have little choice of other land. In a developing country, these are some of the problems in the application of the un-modified USDA system of land capability classification. In any event, the USDA recognized that groupings by use or capabilities should be considered transitory and will need to be changed with changes in technological and scientific inputs which is more likely in new, undeveloped or developing areas. Nevertheless, the basic classification is of utmost importance in any country in assessing the overall quality of the land for agriculture. From it and from a good basic soil survey, specialized groupings can be made for any use, agricultural or other, crop farming systems, etc. The more specific the grouping or classification, the greater is the need for associated collaborative research aimed at getting more complete understanding of soil behaviour and management requirements.

Following on the above considerations, the USDA System was modified suitably to make the classification more realistic for St. Vincent and the Grenadines while at the same time, maintaining the general philosophy of classifying land for agriculture on the basis of the features of the soil and site. In the system developed (Ahmad, 1987), even wider parameters such as the nature of the parent rock and particularly its ability to weather rapidly to reform an eroded soil have been considered. Accessibility which is an important aspect has also been given some importance. In Section 7.0 the land capability classes and sub-classes of the individual soils as classified by Ahmad (1987) are presented. 5.1.1 Previous land capability/land use studies in St. Vincent In the Soil and Land Use Report on St. Vincent, Watson et al. (1958) attempted a land capability classification of the soils of the island. The grouping of the soils was based essentially on slope characteristics at the capability class level as proposed by Kingebiel and Montgomery (1966) and in earlier editions for the USA. 5.2

Bequia

The capability classification of the soils of Bequia was proposed by Ahmad (1987). In Table 1, the relationship of soil slope and land capability classes for the soils is given and in Table 2, the areas for the various slope categories are presented, and as for St. Vincent, where a particular land unit has two slope categories, the dominant slope is used for this computation. Table 3 shows the acreages of the capability classes and sub classes of the soils and in Table 4 is shown a summary of the areas of land in the various land capability classes and sub classes.

Table 1

Relationship of slope classes and capability of the soils of Bequia Slope Classes and angles of slopes

Soil

Series

1 4 6 7 2 5 8 3

Camel Cinnamon Garden Friendship Paget Farm Mt. Pleasant Skeletal soil Spring clay Union Level

Table 2

0-2

2-5 IIIs

IIc*

(degrees) C D 5-10 IVe IVe IIIs IIs

IIs

10-20

20-30 VI

>30

VIIe

VIe

IIIs IIIs

Distribution of land according to slope classes for Bequia Slope

Classes A (0 - 2˚) B (2˚ - 5˚) C (5˚ - 10˚) D (10˚ - 20˚) E (20˚ - 30˚) F > 30˚

Area

Percent

(acres) 262 107 309 191 1097 2514

Total area 5.41 2038 6.90 3.95 22.66 51.90

Table 3 Soil No 1 4 6 7 2 5 8 3

Acreages of the capability classes and sub classes of the soils of Bequia* Soil Series

Camel Cinnamon Garden Friendship Paget Farm Mt. Pleasant Skeletal soil Spring clay Union Level TOTAL

IIc

IIs

IIIe

IIIs

IVe

VIe

VII

225 225

40 37 77

67 50 117

40 45 150 41 276

16 158 174

286 286

811

1814 1814

700 1511

Total 827 265 320 150 81 1814 37 986 4480

Table 4 Class and Sub Class

Distribution of land in the various land capability classes for Bequia* AreaArea â&#x20AC;&#x201C; capability Percent of capability Sub-class Total area class (ac) (ac) Class II 302 6.74 Sub class IIe 225 Sub class IIs 77 Class III Sub class Sub class

393 IIIe IIIs

Class IV Sub class

IVe

Class V Sub class

Class VI Sub class

VIe

Class VII Sub class

VIIe

8.77 117 276

174

3.88 174

286

6.38 286

1,511

33.74 1,511

1,814

40.49 1,814

Total 4,480 * to convert acres to hectares, multiply by 0.405 In attempting a land capability classification of Bequia, in general, the same considerations outlined for St. Vincent were applied. However, the classification of the soils in the two islands is not considered transferable i.e. a soil with one category of classification for St. Vincent must not be considered as having the 14

same agricultural value as a soil similarly classified in Bequia. In Bequia the soils just do not have the same quality as those of St. Vincent in terms of soil depth, soil structure, erodibility, regenerability and accessibility. In addition, the climate and particularly the total rainfall and its annual distribution pose important constraints for agriculture. Within these limitations, the soils on this island are classified on a relative basis. Since all the soils are stony, the identification of stony sub-classes would not have much significance and therefore the classification excludes consideration of stoniness. 6.0

Soil analysis and interpretation of results

6.1

Methods and interpretations

Arrangement were made for the samples of the soils to be analysed by A and L Laboratories in Pompano Beach, Florida, to assess their suitability as agricultural soils. The following determinations were made: Soil pH Organic matter content

(O.M)

Estimated nitrogen release

(ENR)

Cation exchange capacity

(CEC)

Exchangeable cations â&#x20AC;&#x201C; calcium, magnesium and potassium Cation saturation

(percent)

Available phosphorus (Brayâ&#x20AC;&#x2122;s methods) P1 P2 The methods of analysis used were those of the Council for Soil Testing and Plant Analysis (1980). Soil pH was measured using a soil: water mixture according to standard procedure and the values expressed to one decimal. Organic matter was determined using the wet combustion method and estimated nitrogen release was calculated from the organic matter content. In interpreting this value, some caution is necessary since the organic matter content of St. Vincent soils are relatively high and therefore this will yield high values for estimated nitrogen release. For some of the allophanic high level yellow earth soils, however, the organic matter is stable and resists biological degradation to some extent thus retarding the transformation of nitrogen. Therefore, for these soils, the nitrogen release can be over-estimated. Where appropriate, this possibility is stated for the particular soils in discussing their fertility status. 15

The cation exchange capacity (CEC) and exchangeable cations were measured using the standard ammonium acetate extraction procedure and the determination of the cations in the soil extracts were determined, instrumentally. The values for cation exchange were given as c-mol/kg soil and the cations as parts per million. In the report, these were transformed to c-mol/kg soil as for the cation exchange values. Since the CEC is a function of the nature and chemical activity of the inorganic and organic colloidal component of the soil, no ratings of these values have been given. However, ratings for cations in the categories very low (VL), low (L), medium (M), high (H) and very high (VH) have been given for the cations. These ratings are based on the level of cation saturation of the soil by the particular cation. The following table approximates the particular levels of cation saturation with the ratings. Relationships between concentrations of nutrients in c-mol/kg soil and availability ratings for St. Vincent and Bequia Ratings

Calcium

Magnesium

Potassium

CEC

Percent cation saturation Very low

<25

<40

Low

25 – 55

2-5

1.1 – 2.4

40 – 50

Medium

51 – 65

5.1 - 12

2.5 – 3.5

50 – 70

High

61 – 75

12.1 – 20

3.6 – 4

70 – 80

>75

>20

>80

Very High

Available phosphorus was determined by Brays’ method which is widely used for determining the available nutrient in acid soils. Two extractions are involved which are designated as P1 and P2 tests. The extracting reagent for the P1 determination is a mixture of 0.03N ammonium fluoride and 0.025 N hydrochloric acid, which when reacted with the soil, is expected to extract easily acid – soluble form of phosphorus, largely calcium phosphate and a portion of the iron and aluminum held phosphate. The P2 extracting reaction consist of the same chemicals as for the P1 extraction, but with higher concentrations. It is expected that this solution will extract the weakly acid soluble phosphates and a part of the active reserve iron and aluminum held forms. The relationship between P1 and P2 can help evaluate the phosphorus fixing ability of the soil. A wide ratio (greater than 1:3) may be the result of high pH, free calcium, high clay content or use of highly insoluble phosphate fertilizer.

The values for the P1 and P2 phosphate tests are given as parts per million (ppm) and these values have been rated at different levels of availability according to the following scheme: Phosphorus concentrations (Bray P1 and P2) and availability ratings Rating Very low

Available phosphorus (ppm) P1 P2 0-8 0-11

Low

9-17

12-25

Medium

18-26

26-42

High

27-39

43-59

>40

>60

Very high

The estimated nitrogen release (ENR) indicates the potential of the soil to provide nitrogen from its reserves through organic matter breakdown. This will depend on factors such as climatic conditions, soil pH and type of material undergoing decomposition. It is also dependent on the texture of the soil. For instance for the same organic matter content, a soil of light texture is expected to release more nitrogen than a heavier textured soil for any given time interval. The value is calculated based on the organic matter content and texture of the soil and rated as very high (VH), high (H), medium (M), low (L) and very low (VL). The relationship of the numerical values to these ratings varies with the texture of the soil. 6.2

Conversions

The following conversion factors are given with the hope that they may be useful in conversions to the various alternative units in common use in agriculture.

Have (a)+ pounds per acre *parts per million (ppm) tonnes pounds inches miles acres square miles square kilometres c mol/kg soil c mol/kg soil c mol/kg soil c mol/kg soil parts per million phosphorus (P) parts per million phosphorus (P) parts per million potassium (K) parts per million potassium (K)

Need (b)+ kilogramme per hectare pounds per acre tonnes kilograms centimeters kilometres Hectares square kilometres hectares milli-equivalents, per 100g soil parts per million calcium (Ca) parts per million magnesium (Mg) parts per million potassium (K) pounds per acre p2o 5 kilogrammes per hectare pounds per acre K2O kilogrammes per hectare K2O

Conversion (c) 1.12 2 1.016 0.453 2.54 1.609 0.405 2.59 100 *1 200 120 390 4.6 5.15 2.4 2.69

* for depth of soil of six inches (15cm); 15cm (6 inches) depth of most soils would weigh approximately two million pounds. + to convert (b) to (a) divide by conversion factor (c)

7.0

Land capability, fertility assessment, land use recommendations and fertility maintenance.

7.1

Soils of St. Vincent

In this section, the soils will be considered in numerical order according to the listing of Watson et al. (1958).

Soil no. 1

Soil name

Soil classification

Greggs Loam High Level Yellow Earth, and Clay Typic Drystrandepts. Loam

Rainfall (mm>2500 ) Continuously wet

Land area 10,451 ac 4,232 ha

This is a dark brown friable clay loam on lava with moderate erosion hazard and permeability; it occurs on steep hillsides over 200 m elevation and the climate is continuously wet. The main crop on this widespread soil is banana but food crops are also widely grown. Due to the very good soil physical properties, there is only a moderate erosion hazard. The slope categories, capability classes and respective land areas, are given below: Slope class B C D D E

Angle of slope (degrees) 5-10 10-20 20-30 20-30 >30

Land area ac Ha 43 17 1348 546 3246 1315 5550 2748 276 112

Capability classes IIe IIIe Ive Ve Vie

Current land use and characteristics of site sampled: Banana is the main commercial crop on this widespread soil but some plantain and aroids are grown on a commercial basis. There are also other food and vegetable crops mainly in home gardens for domestic use. Significant areas formerly cultivated with banana are now semi-abandoned. The site sampled was located near Greggs on 10 â&#x20AC;&#x201C; 20 degree slope with a good banana crop. Details of the sampling are given below: Soil depth (cm) 0-15 15-30 30-60

Sample number

Remarks

34 35 36

Area in banana on steep slope; few boulders or rock out crops; soil wet especially at depth due to 19

lateral seepage. Soil fertility assessment: The soil analytical results for fertility assessment are given below: Fertility status for Greggs Loam and Clay Loam Sample depth (cm)

Organic matter %

Site No. 1 0-15

5.6

2.0

15-30

5.6

2.0

30-60

5.7

1.4

ENR (kg/ha)

94 M 94 M 81 L

CEC cmol/kg soil

3.3 2.4 1.4

Exchangeable cations cmol/kg soil Ca Mg K 0.85 VL 1.15 M 0.45 L

1.08 VH 0.42 H 0.48 VH

0.59 VH 0.26 VH 0.18 VH

Cation saturation (%)

76 76 79

Avail. P (Bray) ppm P1

12 L 3 VL 2 VL

24 L 7 VL 3 VL

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high

Nitrogen: The values for estimated nitrogen release indicate a high to medium level due to the high organic matter content. However, this is an allophanic soil (high level yellow earth) in which the organic matter is stable with only a slow rate of mineralisation and nitrogen release. The values accordingly over-estimate the level of nitrogen release and in effect this should be rated as low to medium. Phosphorus: The available phosphorus levels indicate low to very low ability of the soil to supply this nutrient which is typical of allophanic soils which have a great capacity to fix the phosphorus in unavailable forms; fertilizer use should therefore emphasize the supply of this nutrient. Potassium: The available form is at a good level; fertilizer use should concentrate less on this nutrient but the level should be periodically monitored. Magnesium: The analytical results indicate a high level of this nutrient and therefore fertilizer use should concentrate less on this nutrient; the usually high levels is a result of continuous use of fertilizers containing this nutrient which is additional to the high natural reserves of the soil. Calcium: The levels in the soil range from low to medium. Due to the correspondingly by high levels of magnesium and potassium, there can be problems for calcium uptake by a high producing crop. The nutrient factor in this soil is delicately balanced and there is not much resilience. Therefore, the ratios of the cations as they relate to fertilizer use should be continuously monitored.

pH value: Although acid, the values are adequate for the present but further acidification may be harmful; continuous monitoring is needed. The need for ground limestone is not presently indicated but this may become necessary. Surface erosion and high leaching result in continuous loss of cations and an integrated approach to land use is strongly indicated. Land use recommendations: Based on the inherent properties of the soil, associated landscape and the present fertility status, the land use recommendations are given below: Slope class

Angle of slope

Recommended crops

Minimum management practices

5-10

Banana, root crops

10-20

Banana, root crops; tree crops

20-30

Banana, tree crops

Some provision for safe drainage of runoff.

>30

Same; planted forest

No tillage; plant all crops on the contour, incorporating bench terraces or individual basins. Same

Minimum tillage; incorporated crop residues; layout cultivation on the contour.

Soil fertility maintenance: Greggs loam and clay loam is a fragile soil with respect to fertility maintenance. At the present time, wherever commercial crops are grown on the soil, there could be nutrient imbalance. A fertilizer with relatively high amounts of phosphorus such as 12:24:12 should be applied every alternate year, rotating with 12:12:17:2 MgO which supplies relatively high amounts of potassium plus magnesium. A fertilizer with magnesium should not be applied every year.

The following rates and application times are recommended: Crop

Annual fertilizer rate kg/ha 700

Banana

Frequency of application 2-monthly intervals; approx one kg/mat/yr

Root crops

400

3 times, during growing period

Vegetable crops

500

in equal doses every 4 â&#x20AC;&#x201C; 6 weeks during growing period

Tree crops

400

in equal doses four times per year

Soil no.

Soil name

Soil Rainfall Land area classification (mm/yr) Gregg Clay Loam High Level Yellow 2120>2500 138ac and Clay Earth Weak dry 56ha (brownish Typic Drystran â&#x20AC;&#x201C; season coloured, depts variant)

This is a friable dark brown clay to clay loam on lava which is closely related to Greggs Loam and Clay Loam. It occurs on steep hillsides and has good drainage with moderately slow permeability. Due to stable soil structure and porous nature, it is fairly resistant to erosion. The slope categories, capability classes and respective land areas are given below: Slope class C D

Angle of slope (degrees) 10-20 20-30

Land area (ac) (ha) 74 30 64 26

Capability classes IIIe IVe

Current land use and other characteristics of site sampled: This soil is mainly in root-crops and other food and vegetable crops; some banana and plantain are also cultivated. The site sampled was located at Upper Bel Air on land owned by a Mr. Garcia; it was occupied by mixed food and vegetable crops on narrow beds (one metre wide) laid out on the contour.

Details of the sampling are given below: Soil depth (cm) 0-15 15-30 30-60

Sample number

Remarks

52 53 54

Area fairly built up; no mulching or surface protection other than that of the crop being grown.

Soil Fertility Assessment: The analytical results for fertility assessment are given below: Sample depth (cm)

Organic matter %

0-15

5.4

1.2

15-30

5.6

1.7

30-60

5.9

1.7

ENR (kg/ha)

82 M 78 M 78 M

CEC cmol/kg soil 9.7 11.4 11.7

Exchangeable cations cmol/kg soil Ca Mg K 3.25 2.08 1.61 L VH VH 5.6 2.16 0.90 M VH VH 6.75 2.23 0.66 M VH VH

Cation saturation (%) 71 76 82

Avail. P (Bray) ppm P1 3 VL 2 VL 2 VL

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high

Chemical activity: The cation exchange capacities are distinctly higher than the related Greggs Loam and Clay Loam due to lower rainfall, not as profound leaching and the related occurrence of smectite, halloysite and kaolinite clay minerals in addition to allophane. Nitrogen: Medium levels of estimated nitrogen release are indicated by the data but due to the stable nature of the organic matter, the actual values could be lower, most likely in the low to medium range. Phosphorus: Very low values for available phosphorus were obtained which resulted from the very strong chemical bonding in this soil, in which allophane is important. The values are also indicative of the fact that since the cropping was not banana, the level of fertilization was much lower. Also, in this farming regime, surface erosion may be a serious hazard. Potassium: High values for exchangeable potassium were obtained due partly to the high inherent reserves as well as to the residual effect of fertilizers. Calcium: The effect of leaching on the values for exchangeable calcium is clearly seen. There are no additions of this cation in the form of soil amendments. The calcium levels should be monitored to determine at what stage the use of ground limestone may be needed. 23

P2 8 VL 7 VL 3 VL

Magnesium: Very high values were obtained for this nutrient partly due to high soil reserves as well as to continuous additions of fertilizers. pH value : This is adequate at the present time but there is a tendency for the value to decrease with time as for exchangeable calcium. Periodic monitoring is necessary. Land use recommendations: Based on the inherent properties of the soil, associated landscape and the present fertility status, the land use recommendations are given below: Slope Class C

Angle of Recommended crops Minimum management slope practice (degrees) 10-20 Banana, root crops, Minimum tillage, other food and incorporate crop residues. vegetable crops Individual basins; land layout on contour; run-off drains; grass strips. 20-30

Banana, tree crops

- ditto -

Soil fertility maintenance: As for Greggs Loam and Clay Loam (Soil No. 1)

Soil no. 3

Soil name Montreal Loam and Clay Loam

Soil Rainfall classification (mm/yr) High Level Yellow >2500 Earth continuously Typic Dystranwet depts.

Land area 3,573 ac 1447 ha

This is a very friable dark brown to dark yellowish brown clay loam on tiff with moderate to low erosion hazard and medium permeability. It occurs mainly on hummocky topography over 200m elevation with annual rainfall >2500mm and continuously moist. There are also occurrences on steeper slopes. This is a typical Andisol dominated by allophanoid clay minerals. While the main commercial crop on this widespread soil is banana, other crops such as aroids, sweet potato and ginger are also commercially grown. Due to the very good physical properties and gentle slope, erosion is not a very serious

problem. The slope categories capability classes and respective land areas are given below: Slope class B C C-D D E F

Angle of slope (degrees) 2-5 5-10 5-20 10-20 20-30 >30

Land area (ac) (ha) 24 10 398 161 777 315 1062 430 999 405 313 127

Capability classes I IIe IIIe IIIe Ive Ve

Characteristics of soil and sites sampled: The Montreal soil is well known for its excellent physical properties and problematic fertility status. For this reason two sites were sampled in different geographic areas with the aim of assessing whether different management regimes could influence soil behaviour. The first site was located in a banana cultivation adjacent to the Montreal Gardens in the Montreal District on 3˚ – 5˚ slope. The crop was in ratoon and appeared in good condition. Land use in the area consisted of fallow, banana and food crops. There was a nearby abandoned citrus field in which the trees were in very poor condition, showing many nutrient deficiency symptoms. Site 2 was located near Lowmans on about 20 0 – 300 slope, in mid-slope position. The site appeared to have undergone some soil erosion. The crop was in about 3.5 months old banana which looked well but the cultivation was weedy; the main weed was Comelina elegans. Details of the samplings are given below: Sample depth (cm) Site 1 (Montreal) 0-15 15-30 30-60 Site 2 (Lowmans) 0-15 15-30 30-60

Sample number

Remarks

145 146 147

Little or no evidence of erosion; soil moist to wet.

soil

46 47 48

Some erosion; crop looked better in lower slope position

Soil fertility assessment: The soil analytical results for fertility assessment are given below Sample depth (cm)

Site 1 (Montreal) 0-15 5.0

Organic matter %

5.6

15-30

5.0

5.2

30-60

5.0

3.6

Site 2 (Lowmans) 0-15 6.0

2.6

15-30

5.9

2.7

30-60

5.8

2.2

ENR (kg/ha)

CEC cmol/kg soil

175 VH 166 VH 130 H

1.6

108 M 110 M 99 M

7.8

1.6 1.5

6.7 4.6

Exchangeable cations cmol/kg soil Ca Mg K

Cation saturation (%)

Avail. P (Bray) ppm P1

0.65 L 0.70 L 0.70 L

0.21 L 0.18 L 0.18 L

0.06 VL 0.04 VL 0.04 VL

58 M 58 M 61 M

8 VL 3 VL 2 VL

17 VL 4 VL 3 VL

3.25 L 2.60 L 1.95 L

1.58 VH 1.25 VH 0.83 VH

1.72 VH 1.69 VH 1.0 VH

84 VH 83 VH 82 VH

1 VL 1 VL 5 VL

3 VL 4 VL 8 VL

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high

Chemical activity: The soil has typical allophanic properties with low levels of cation exchange capacities and with a high amount and deep incorporation of organic matter; leaching losses of nutrients can be important. Nitrogen: The estimated nitrogen release for the two sites ranged from medium to very high. However, as for Greggs loam and clay loam, these values do not necessarily indicate a high degree of availability due to the considerable biological stability of the soil organic matter in these allophanic soils. In terms of availability, they can better be rated as low to medium. Phosphorus: As is well established for the Montreal soils (Macfarlane and Walmsley, 1977), available phosphorus is very low for both sites at all depths. This is due to the strong fixation of any added phosphates, the soil having a great capacity for this. Their successful use for agriculture depends on continuous heavy application of phosphate fertilizers and prevention of erosion. Potassium: Available potassium for the two sites show a marked difference, ranging from very low in Site 1 to very high in Site 2. This is a reflection of differential management over a period of time and the history of banana cultivation and associated fertilization regime.

Magnesium: The distribution of magnesium follows the same pattern and levels as for potassium which may be again related to the previous agricultural history of the sites. Future fertilizer use should take account of these differences. Calcium: Low values for calcium are indicated for both sites but the levels are not critically low. Native soil reserves would maintain these levels and it is important, in management, not to upset the calcium: magnesium ratio through indiscriminate fertilizer use. pH values: Values for Site 1 are low and can even indicate the need for the use of some ground limestone but for Site 2 the values are much higher. Apart from the influence of land use and crop management on these differences, greater leaching for Site 1 which is located in a higher rainfall zone (continuously moist) may be partly responsible. It would be difficult to change these values which at any rate are not viewed as critically low for crop production. Land use recommendations: Based on the inherent properties of the soil, associated landscape and the present fertility status, the land use recommendations are given below: Slope class B, C, D E, F

Angle of Recommended slope crops (degrees) 2-20 Banana, aroids, ginger, tree crops 20 - >30 Some banana, tree crops, agroforestry

Minimum management practice Minimum tillage; individual basins for banana and tree crops; run-off drains. Plant on the contour, individual basins or terraces, contour or run-off drains.

Soil fertility maintenance: Montreal loam and clay loam is a fragile soil with respect to fertility maintenance; Except for phosphorus, other nutrients are easily leached and their balance can be influenced by use of fertilizers. At the present time there is an imbalance of the cations calcium, magnesium and potassium which should influence future use of fertilizers. A fertilizer with high phosphorus levels such as 12:24:12 should alternate with one containing magnesium such as 12:12:17:2 MgO every other year.

The following kinds, rates and times of application for the various crops on an annual basis are recommended: Crops Banana Root crops Tree crops

Soil no.

Annual fertilizer rate Frequency of application (kg/ha) 700 Approx 1.5 kg/mat/yr applied in 2monthly intervals 400 3 times during growing season 400 3-monthly intervals

Soil name

Soil Rainfall classification (mm/yr) Montreal Loam High Level Yellow >2500 and Clay Loam Earth (Continuously (imperfectly Aquic Dystran- moist) drained variant) depts

Land area 57 ac 23 ha

This is a dark yellowish brown to yellowish brown loam over tiff on gentle slopes with moderate erosion and permeability. It occurs in flatter areas in the highland region and particularly within other Montreal soils. The elevation is >200m. The slope, capability class and land area are given below: Slope class C

Angle of slope (degrees) 5-10

Land area (ac) (ha) 57 23

Capability class 11b

Current land use and characteristics of site sampled: The sample site was located near Hopewell in the Montreal District on the crest of a 3Ë&#x161;-4Ë&#x161; slope; the sub-soil appeared mottled but this phenomenon was probably due to weathering effects of the various rock minerals. The main agricultural land use in the area was banana and mixed food crops particularly pigeon pea and eddo which appeared in fair to good condition. Details of the sampling are given below: Soil Depth (cm) 0-15 15-30 30-60

Sample number 112 113 114

Remarks Few large boulders or stone outcrops; area largely residential

Soil fertility assessment: The soil analytical results for fertility assessment are given below: Sample depth (cm)

Organic matter %

ENR (kg/ha)

CEC cmol/kg soil

0-15

5.5

1.6

9.8

15-30

5.4

1.5

30-60

5.6

1.6

85 M 83 L 85 M

10.2 8.7

Exchangeable cations cmol/kg soil Ca Mg K 5.05 1.83 0.37 M VH H 5.50 1.67 0.26 M VH M 5.05 1.37 0.15 M VH L

Cation saturation (%) 74 H 73 H 74 H

Avail. P (Bray) ppm P1 12 L 11 L 10 L

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high

Chemical activity: A fair to good level of chemical activity is indicated by the cation exchange capacity (8.7 to 10.2 cmol/kg soil). In addition, in common with the other Montreal soils a high level of phosphate fixation is expected. Nitrogen: Low to medium rate of release of available nitrogen is indicated but in reality this would be lower due to stability of the organic matter to biological degradation. Phosphorus: Generally, low levels of availability are characteristic but this can be influenced by fertilizer use and management. Fixation is relatively slow following fertilizer applications, thus giving crops the opportunity for uptake. Potassium: There is medium to high availability and this is no doubt influenced by continuous use of fertilizers rich in potassium. Calcium: Medium levels of availability are indicated with no immediate dangers of deficiency of this nutrient; however, the high magnesium levels could cause a nutrient imbalance with suppression of uptake of calcium. pH values: For the present, the values are satisfactory; however, the situation should be monitored. Soil fertility maintenance: The recommended cropping, management and fertilizer use recommended for Montreal Loam and Clay Loam (B, C and D Slopes) apply to this soil as well.

P2 40 M 33 M 22 L

Soil no. 5

Soil name

Soil Rainfall classification (mm/yr) Montreal Loam High Level Yellow >2500 and Clay Loam Earth continuously (poorly drained moist variant)

Land area 363 ac 147ha

This is a very friable dark brown to dark yellowish brown clay loam occurring in depressions within other Montreal soils. It has very poor drainage and very slow permeability; the top soil is almost peaty with matted roots. The elevation is >200m. The slope, capability class and land area are given below: Slope class B

Angle of slope (degrees) 2-5

Land area (ac) (ha) 363

Land capability

147

IIIs

Current land use and characteristics of site and soil sampled: The site was located in a depression in the Montreal area not far from the Montreal Gardens. The soil felt somewhat spongy under-foot and it was very wet; the water-table was about 25 cm from the surface and the native vegetation consisted of mixed grasses. The actual site was in temporary fallow but the area around was either used for rough pasturage or was cultivated with aroids and sweet potato on small ridges; commercial banana production was noticeably absent. Details of the sampling are given below: Sample depth

Sample

Remarks

(cm) 0 â&#x20AC;&#x201C; 15 15 â&#x20AC;&#x201C; 30 30 - 60

No. 142 143 144

Concave relief; very wet; decrease in dark coloration with depth

Soil fertility and assessment: The soil analytical results for fertility assessment are given below: Sample pH Organic ENR CEC Exchangeable Cation Avail. P depth matter (kg/ha) cmol/kg cations saturation (Bray) (cm) % soil cmol/kg soil (%) ppm Ca Mg K P1 P2 0 - 15 5.9 6.6 197 2.5 1.35 0.69 0.06 84 9 24 VH 15- 30 5.6 5.1 166 1.5 0.80 0.33 0.08 81 7 23 VH M H L VH VL L 30 - 60 5.5 4.6 152 1.4 0.70 0.27 0.05 73 9 19 VH H H L H VL L ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high

Chemical activity: This is an allophanic soil with a low level of adsorption of cations as indicated by low cation exchange capacity throughout. The organic matter is stable and its activity is reduced by adsorption of hydrous oxides. Added fertilizers are subject to rapid leaching. Nitrogen: The total estimated nitrogen release is high but this is an over-estimate as pointed out before for other allophanic soils. Phosphorus: Values for available P are low indicating a high level of fixation. Fertilizer use should emphasise this nutrient. Potassium: Values are low which is more characteristic of low natural fertility since this soil most likely had not received much fertilization in the past due to non-cultivation of banana. Magnesium: Relative to other cations, magnesium levels are high to very high. In this soil, this is inherited from parent rocks and not necessarily due to residual fertilization. In agricultural use, additions of magnesium are not necessary. Calcium: Values are medium to high, which indicates a satisfactory ratio of the cations; it is important not to create an imbalance by the use of magnesium containing fertilizers. pH Value: The values are good for satisfactory plant growth and no additions of ground limestone are needed.

Land use recommendations: A prime need for any improved agricultural use of this soil is drainage which is possible to improve, despite the concave relief. With improved drainage, crops such as aroids particularly dasheen, carrot and celery seem good prospects which could be facilitated by the excellent soil physical properties. Fertilizer use should emphasise phosphorus and nitrogen with moderate amounts of potassium. The need for magnesium is not indicated. Based on the inherent properties of the soil, associated landscape features and the present fertility status, the land use recommendations are given below: Slope class 2-5

Angle of Recommended crops slope (degrees) B Dasheen, Celery and Carrots

Minimum management practices Improvements of external drainage; land layout in small ridges or beds; minimum tillage

Soil fertility and maintenance: Fertilizers should be used with caution to avoid nutrient imbalance or over-use. Between 300 - 400kg/ha of 12:24:12 should alternate on an annual basis with the same amount of 13:13:21. Split applications at 6 weeks to 2 monthly intervals during the growing period of the crop should be used.

Soil no. 6

Soil name

Soil Rainfall classification (mm/yr) Montreal Loam High Level Yellow >2500 and Clay Loam Earth continuously (alluvial/colluvial Typic Dystrandepts moist variant)

Land area 75 ac 30ha

This is a dark brown to dark yellowish brown friable clay loam on tiff; it has moderate erosion hazard good, permeability and it is bouldery. It occurs on relatively flat lands and low hills within the Montreal family of soils. The slope categories and capability class are given below. Slope class B

Angle of slope (degrees) 2â&#x20AC;&#x201C;5

Land area (ac) (ha) 75

Land capability IIb

Current land use and characteristics of soil and site sampled: The site was located close to the site for soil no. 5 in Hopewell, Montreal District on very gently sloping land (1˚ - 3˚ slope); mixed food crops were being cultivated at the site, but banana was the dominant crop in the area. Details of the sampling are given below Sample depth (cm) 0 - 15 15 - 30 30 - 60

Sample no. 115 116 117

Remarks Compared to site for Soil No. 5, there was no “mottling” but colour changed to more yellowish at depth

Soil fertility assessment: The soil analytical results for fertility assessment are given below. Sample pH Organic ENR CEC Exchangeable Cation Avail. P depth matter (kg/ha) cmol/kg cations saturation (Bray) (cm) % soil (%) ppm Ca Mg K P1 P2 0 - 15 4.8 1.8 90 4.1 1.05 0.62 0.62 56 16 43 M VL H VH L H 15 - 30 4.7 1.1 74 4.1 0.85 0.67 0.56 51 11 25 L VL VH VH L L 30 - 60 4.9 1.6 85 2.8 0.75 0.45 0.42 58 3 10 M L H H VL L ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high

Chemical activity: This is an allophanic soil with weak to moderate levels of chemical activity. The fairly low cation exchange capacities indicate a weak retention of nutrients except phosphorus which is firmly fixed by the hydrous oxides and organic matter. Nitrogen: The low to medium availability indicated by the analytical result is an over-estimate due to the great stability of the organic matter and its resistance to biological breakdown and mineralisation of the nitrogen. The availability is most likely in the low category.

Phosphorus: The values which are good, reflects residual effects of previous fertilizer use. These levels should be maintained or improved for continued satisfactory crop production. Potassium: Values range from high to very high which indicate both the influence of the soil parent material and previous fertilizer use. Magnesium: Values range from high to very high, again reflecting native soil reserves. Future fertilizer use should take into account these high levels and prevention of an imbalance of nutrients. Calcium: Values are low to the point where the soil can benefit from the use of ground limestone. pH value: The values for this soil (4.7 to 4.9) are the lowest for any soil in St. Vincent and Bequia and indicate that there could be some benefit from the use of ground limestone. This is corroborated by the low levels of exchangeable calcium. Land use recommendations: This is a minor soil which occurs as inclusions within other Montreal soils and particularly Montreal loam and clay loam. Therefore, recommended use for this more widespread soil should apply. Based on the inherent properties of the soil, associated landscape features and the present fertility status, the land use recommendations are given below: Slope class B

Angle of slope (degrees) 2-5

Recommended crops

Minimum management practices

Banana, plantain, aroids, Minimum tillage; incorporation of food and vegetable crop residues; ridging for annual crops crops and individual basins for banana and plantain

Soil fertility maintenance: Same as for Montreal loam and clay loam on B, C and D slopes would apply for this related soil. However, ground limestone can be tried at about 1,000 pounds per acre applied in the planting zones only.

Soil no. 7

Soil name

Soil Rainfall classification (mm/yr) Lettswood High Level Yellow >2500 Gravelly Sandy Earth continuously Loam to Gravelly Typic Dystrandepts moist Clay Loam

Land area 2,665 ac 1079 ha

This is a friable dark brown to dark yellowish brown sandy loam to gravelly clay loam on tuff and loose agglomerate with moderate permeability and good drainage; it occurs on steeply sloping mountain land of over 60m elevation. There is a serious erosion hazard. The slope categories and capability classes are given below: Slope class Angle of slope Land area Capability class (degrees) (ac) (ha) B 5 - 10 46 19 IIe B-C 5 - 20 86 35 IIIe D 20 - 30 156 63 IVe D 20 - 30 930 377 Ve D-F 20 - >30 1348 546 VIe F >30 98 40 VIIe Current land use and characteristics of soil and site sampled: The site was located about 3.5 miles (5.6km) westwards in the Richmond area. It had a good banana crop and was on about 25Ë&#x161; slope. Banana was the dominant crop in the area. Details of the sampling are given below: Sample depth (cm) 0 - 15 15 - 30 30 - 60

Sample No. 22 23 24

Remarks Mountainous land with steep slopes

Soil fertility assessment: The soil analytical results for fertility assessment are given below: Sample depth (cm)

Organic matter %

ENR (kg/ha)

CEC cmol/kg soil

0 - 15

5.7

2.0

7.3

15- 30

6.0

2.1

30 - 60

6.3

2.1

84 M 86 M 86 M

10.3 9.6

Exchangeable cations cmol/kg soil Ca Mg K 3.9 1.14 0.69 M VH VH 6.65 1.46 0.49 M H VH 7.0 1.21H 0.39 H VH

Cation saturation (%) 78 83 89

Avail. P (Bray) ppm P1 P2 26 43 M-H H 9 20 VL L 5 20 VL L

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high

Chemical activity: There is a good level of chemical activity as indicated by the cation exchange capacity values. The soil has a satisfactory ability to retain nutrients and strong capacity for fix phosphate. Nitrogen: The estimates of nitrogen release may be higher than it actually is due to the allophanic nature of the soil. The actual levels most likely is low to medium. Phosphorus: The higher levels in the surface layer is due to residual effects of continuous use of mixed fertilizers; it is therefore very important to preserve this layer from erosion. Potassium: The values are good for a fertile soil and only a maintenance level of fertilization is now needed. Calcium: The values are indicative of a fertile soil; there is no need for the use of ground limestone. pH value: pH values are ideal for good crop growth; no corrective measures are needed. Land use recommendations: This is a very good soil but the steep slopes pose some constraint to wide agricultural use. At all times appropriate treatment for erosion control should be practised. Based on inherent properties of the soil, associated landscape features and the present fertility status, the land use recommendations are given below:

Slope class B B-C D

Angle of slope (degrees) 5-10 5-20 20-30

D-F F

20->30 >30

Recommended crops

Minimum management practices

Banana, plantains aroids Minimum tillage; plant food and vegetable along contour; and crops individual basins; run-off drains; grass strips. Banana on lesser slopes, permanent crops elsewhere; agro-forestry and cultivated forests.

Plant in individual basins, terraces where possible; run-off drains; consult experts.

Soil fertility maintenance: Rotate 12:24:12 and 13:13:21 annually for banana at 700 kg/ha (approx. 1kg/mat/yr) applied in split applications once every two months; same fertilizers for food and vegetable crops at 400kg/ha applied in splits at 6 weekly intervals during growing period. For tree crops, apply 400kg of the fertilizers per year at three monthly intervals, placed per tree. The soil should be checked for fertility status on biennual basis and fertilizer use can be regulated accordingly. For the time being it seems advisable to avoid fertilizers with magnesium.

Soil no. 8

Soil name

Soil Rainfall classification (mm/yr) St. Vincent Loam Low Level Yellow 2250 - 2500 and Clay Loam Earth (Typic mm weak dry Eutropepts) season

Land area 5952 ac 2410 ha

This is a friable dark brown clay loam on volcanic agglomerate with moderate erosion hazard and permeability; it occurs on fairly steep terrain below 200m elevation in an annual rainfall regime of 2125 to 2500 mm with a weak dry season. The main crop is banana but on this widespread soil, there is a diversity of cropping. The slope categories, capability classes and respective land areas are given below:

Slope class C C D D D E-F

Angle of slope (degrees) 5-10 5-10 10-20 10-20 20->30 20->30

>30

Land area (ac) (ha) 278 112 32 13 446 181 1340 543 174 70 1406 569 1780 721 496 201

Capability classes IIe IIb IIIe IVe IVb Ve VIe VIIe

Current land use and characteristics of soil and site sampled: The site selected was in Upper Buccament Valley in an area with mixed cropping with banana being dominant. The sampled area was in food crop production although the actual site was in temporary fallow; good sweet potato and aroids are also grown in the area; the slope of the site was about 20 0. Details of the sampling are given below: Soil depth (cm) 0-15

Sample number 65

15-30

30-60

Remarks This is an extensive soil and although banana is the main crop other crops like sweet potato and aroids normally grown in St. Vincent are also cultivated.

Soil fertility assessment: The soil analytical results for fertility assessment are given below: Sample depth (cm)

Organic matter %

ENR (kg/ha)

0 - 15

6.2 M 6.4 M 6.3 M

2.1

96 M 96 M 92 M

15- 30 30 - 60

2.1 1.9

Exchangeable cations cmol/kg soil CEC 10.3 10.2 12.3

Ca 6.00 M 5.90 M 7.60 M

Mg 3.00 VH 3.33 VH 2.50 VH

Cation saturation (%) K 0.15 L 0.33 M 0.26 L

89 94 85

Bray Avail. P (ppm) P1 P2 22 34 L M 17 27 L M 6 9 VL VL

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high

Chemical activity: A good level of chemical activity is indicated by the cation exchangeable capacity values and depth and penetration of organic matter. Nitrogen: A good available nitrogen level from which it is expected that more than 50 percent of the nitrogen used by a productive banana crop for instance may be supplied from soil reserves. Phosphorus: There is residual effect of phosphorus from previous fertilizer use which is concentrated in the surface layer - this indicates the importance of preserving this layer against erosion. A good part of the cropâ&#x20AC;&#x2122;s needs can be obtained from soil reserves. Potassium: The available form is low in the surface layer but it increases with depth. Since most of the uptake is from this layer, fertilizer supplementation is needed. Magnesium: Available levels are very good and no additions are needed. Calcium: The degree of saturation of the soil is very adequate and no amelioration is necessary. pH value: Very good; there is no need for the use of ground limestone.

Land use recommendations: Slope class 5-10

Angle of Recommended crops Minimum management slope practices (degrees) IIe and IIb Banana, aroids, food Minimum tillage; incorporate and vegetable crops. crops residues; arrange land layout and crop planting along the contour.

10-20

IIIe. IVe

10-20

IVb

VIIe 20>30

Ve and VIe

>30

VIIe

Same

Banana, tree crops

Minimum tillage; crop planted in individual basins on the contour; grass strips.

Banana, tree crops, Minimum tillage; all cultural cultivated forests. operations manually done; crop planting in individual basins; silt trap or storm drains; consult specialists re. structures Tree crops cultivated forests

and - ditto

Soil fertility maintenance: Banana: 700 kg/ha annually (approx. one kg/mat/yr) but rotate with 12:24:12 and 13:13:21; no magnesic fertilizer is needed. Aroids: 400kg/ha annually but rotate with 12:24:12 and 13:13:21; mangesic fertilizer is not needed. Tree crops: 400 kg/ha 12:24:12 in split applications every 2 months during the wet season.

Soil no. 9

Soil name

Soil Rainfall classification (mm/yr) St. Vincent Low Level Yellow 2250-2500 Gravelly Loam Earth Weak dry and Gravelly Typic Eutropepts season Clay Loam

Land area 371 ac 150 ha

This is a dark reddish brown to dark brown gravelly loam on indurated volcanic agglomerate with rapid drainage, medium permeability and moderate erosion. The soil occurs on steep hillsides. There is severe erosion hazard and many rock outcrops. The slope categories and capability classes are given below: Slope class F

Angle of slope (degrees) >30

Land area (ac) (ha) 371 150

Capability Class VIIe

Current land use and characteristics of site sampled: The site was located near Wallilabou on very steep land. The area was mostly in secondary growth; there are no access routes and the slopes are very steep. Details of the sampling are given below: Soil depth (cm) Sample number 0-15 163

Remarks Soil rocky and gravelly; steep slopes

Soil fertility assessment Only the surface layer 0 - 15cm, was sampled; the analytical results are given below: Sample depth (cm)

Organic matter %

ENR (kg/ha)

CEC cmol/kg soil

0 - 15

6.2

2.8

92 M

10.4

Exchangeable cations cmol/kg soil Ca Mg K 6.8 0.34 0.28 M H M

Cation saturation (%) 96 H

Avail. P (Bray) ppm P1 6 VL

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high According to data in the table above, this is a fertile and potentially productive soil. The available potassium and phosphorus are not as high as if the site were in productive agriculture and received fertilizers. Constraints to agricultural use would be lack of access, steep slopes, bouldery and gravelly soil. 41

P2 9 VL

Land use recommendations: The soil should be used for conservation purposes. It can be made productive through the introduction of tree crops and agro-forestry but in establishing these uses, the land should not be completely cleared. The planted crops should be arranged on the contour and planted at least in individual basins. Access at all levels should be given prime consideration.

Soil no. 10

Soil name

Soil Rainfall classification (mm/yr) Westwood Low Level Yellow 2250 - 2500 Gravelly Loam Earth Weak dry and Gravelly Typic Eutropepts season Clay Loam

Land area 1402 ac 568 ha

This is a dark yellowish brown to yellowish brown gravelly loam with small stones and friable consistency. It is formed on loose agglomerate and ash and has good drainage, moderate to good permeability and moderate erosion hazard. It occurs below 200m elevation on steep slopes; there is a severe erosion hazard. The slope categories and capability classes are given below: Slope class Angle of slope Land area (degrees) (ac) (ha) C 20-30 1304 528 D-F

20 - >30

Capability classes Ve

VIe

Current land use and characteristics of site sampled: The site was located near Coulls Hill in a good plantain cultivation inter-cropped with other food crops; the farmer reputedly was not using fertilizers on the current crop; however, the history of previous land use was not known. Details of the sampling are given below: Soil depth (cm) 0-15

Sample number 87

15-31

30-60 Soil fertility assessment:

Remarks The cultivation was well maintained.

The soil analytical results for fertility assessment are given below: Sample

Organic

ENR

CEC

Exchangeable

Cation

Avail. P

depth (cm)

matter %

(kg/ha)

cmol/kg soil

88 M 80 M 78 M

15.3

0-15

6.2

2.2

15-30

6.2

1.8

30-60

6.5

1.7

14.6 14.3

cations cmol/kg soil Ca Mg K 10.3 2.58 0.57 H VH VH 9.9 2.58 0.35 H VH M 10.25 2.67 0.34 H VH M

saturation (%) 88 VH 88 VH 93 VH

(Bray) ppm P1 39 M 23 L 32 M

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high

Chemical activity: This soil has a high degree of chemical activity with a high cation exchange capacity and a good level and deep penetration of organic matter. It is expected to be retentive of fertilizers and with only moderate erosion hazard; it can be described as a fertile soil. Nitrogen: The estimated nitrogen release indicates an ability to supply a good amount of nitrogen to the crop, hence a good plantain crop without fertilizer use. However, for sustained cropping supplemental nitrogen would be needed. Phosphorus: A very good level of available phosphorus was indicated which was sustained up to 60 cm depth. The inference is that this may not be due only to residual effects of previous fertilizer use but also to an inherently high level of the nutrient in the soil parent material. Potassium: A very good level of available potassium was obtained which was sustained at depth indicating, like for phosphorus, the combined effects of previous fertilizer use and parent materials rich in potassium. Magnesium: Very high levels of available magnesium were obtained which was sustained at depth and indicate the influence of the soil parent materials. Calcium: There is an ideal level of saturation of the soil with calcium, resulting in a high degree of cation saturation. pH value: The values indicate ideal conditions for crop growth with no need for use of ground limestone.

P2 58 H 62 VH 39 VH

Land use recommendations: Slope Angle of Recommended crops class slope (degrees) D 20 - 30 Banana*; plantain*; aroids; food crops D-E 20 - >30 Banana*; plantain; tree crops

Minimum management practices Minimum tillage; individual basins; grass strips; run-off drains. Minimum tillage; terraces; run-off drains; grass strips.

* with irrigation Soil fertility maintenance: This is a fertile soil and if well managed to prevent accelerated erosion, can remain productive. The levels of nutrients present in the soil indicate a well balance situation and fertilizer use should really only concentrate on maintaining and enhancing the present levels. Supplemental nitrogen, phosphorus and potassium in that order is indicated and therefore a fertilizer such as 20:10:10 at 400500kg/ha applied in splits at 2 â&#x20AC;&#x201C; 3 monthly intervals during the growing or wet season is recommended for most crops.

Soil no. 11

Soil name

Soil Rainfall classification (mm/yr) Claxton Clay Low Level Yellow 1875-2125 Loam and Clay Earth Marked dry Typic Tropudalfs season

Land area 2854 ac 1156 ha

This is a dark reddish brown to dark yellowish brown friable clay loam on lava; it has good drainage, moderate permeability and moderate erosion hazard; there are some rock out-crops; this is a widespread soil in the southern part of the island. It occurs in upland areas with normal relief. The slope categories, capability classes and respective land areas are given below: Slope class B C C C-D C D E, F

Angle of slope (degrees) 5-10 10-20 5-10 10-30 10-30 20-30 >30

Land area (ac) (ha) 228 92 1338 542 282 114 61 25 110 44 800 324 35 14

Capability classes IIe IIIe IIIb IVe IVb Ve VIe

Current land use and characteristics of site and soil sampled: The sample site was located near Enham; the area had some banana which was most likely irrigated but also food crops; the site used for sampling was cultivated with pigeon pea and sweet potato. Details of sampling are given below: Soil depth (cm) Sample number 0-15 43 15-30 44 30-60 45

Remarks Soil used successfully for a wide range of crops

Soil fertility assessment: The analytical results for fertility assessment are given below: Sample depth (cm)

Organic matter %

0-15

6.4

1.3

15-30

6.2

1.6

30-60

6.2

1.4

ENR (kg/ha)

78 L 85 M 81 M

CEC cmol/kg soil 12.4 12.4 13.3

Exchangeable cations cmol/kg soil Ca Mg K 7.4 3.33 0.59 M VH VH 7.8 2.67 0.48 M VH VH 9.05 2.58 0.09 H VH VL

Cation Saturation (%) 91 VH 88 VH 88 VH

Avail. P (Bray) ppm P1 2

P2 3

2 VL 1 VL

3 VL 2 VL

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high

Chemical Activity: This soil has a good level of chemical activity as indicated by the cation exchange capacity and amount and penetration of organic matter. Nitrogen: This is a soil in continuous agricultural production so the estimated nitrogen release and organic matter levels are low for St. Vincentâ&#x20AC;&#x2122;s soils. Nevertheless a substantial amount of the nitrogen requirement of the main food crops for which this area is naturally suitable can be supplied from the soil reserves. Phosphorus: Available forms of this nutrient are low to very low which is indicative of the non-cultivation of banana and associated with levels of fertilizer applications on a continuous basis. Successful future cropping should be associated with additions of phosphorus. Potassium: The levels of nutrient up to 30 cm depth are very good but there is a sharp decrease deeper in the soil. This is due to the influence of soil parent materials. For good crop production only maintenance levels are required.

Magnesium: Relative to the other cations, magnesium levels are high throughout the profile which is due to the high magnesium content of the parent materials. Calcium: The levels range from medium to high which is in the ideal range for a fertile soil; no supplementation is required. pH value: The range is ideal for crop growth and no corrective measures are needed. Land use recommendations: Based on the inherent properties of the soil, associated landscape and the present fertility status, the land use recommendations are given below: Slope class

Angle of slope (degrees)

Recommended Crops

Minimum management practices

B-D

5-30

Food and vegetable crops including plantain and banana where irrigation is possible

Minimum tillage. grass strips; contour bunds ; terraces; runoff drains, moisture conservation measures

E-F

>30

Tree crops - mango, Terraces for access, individual guava, citrus, sour sop, basins; control of run-off, sugar apple moisture conservation

Soil fertility maintenance: This is a naturally fertile soil; fertilizer use should concentrate on supplying nitrogen and phosphorus since the cations potassium, calcium and magnesium are in good supply. For food and vegetable crops, 12:24:12 should alternate on a yearly basis with 20:10:10 at the rate of 300 - 400 kg/ha applied in split applications during the growing period. For tree crops, the same fertilizers in alternate years should be applied at about 200 - 300 kg/ha on an individual tree basis; as the trees approach maturity, the fertilizer rates can be increased; the fertilizers should be applied during the wet season 3 - 4 times per year.

Soil no. 12

Soil name

Soil Rainfall classification (mm/yr) Kings Sandy Clay Low Level Yellow 1975 - 2125 Loam and Clay Earth Marked dry Loam Typic Tropudalfs season

Land area 357 ac 144 ha

This is a friable dark brown changing to yellowish red sandy clay loam on pebbly agglomerate with good drainage and permeability. It occurs on landscapes less than 200m in elevation with steep topography. There is a severe erosion hazard and there are steep and shallow phases. The slope categories and capability classes are given below: Slope class Angle of slope Land area (degrees) (ac) (ha) B 2-5 10 4 C 5-10 6 2 E 10-20 9 4 E 20-30 197 80 C >30 54 22

Capability classes I IIe IVe Ve VIe

Current land use and characteristics of site sampled: The site was located at Akers Hill and was planted with sweet potato; this was the dominant crop on this soil in the area although some banana was also being produced. Details of the sampling are given below. Soil depth (cm) Sample number 0-15 40 15-30 41 30-60 42

Remarks Soil dark brown to sampling depth - only slight change with depth.

Soil fertility assessment: The soil analytical results for fertility assessment are given below: Sample depth (cm)

Organic matter %

ENR (kg/ha)

CEC cmol/kg soil

0-15

6.5

1.7

12.9

15-30

6.3

1.4

30-60

6.7

1.0

87 M 81 L 72 L

13.1 17.2

Exchangeable cations cmol/kg soil Ca Mg K 7.75 3.0 1.08 M VH VH 8.05 2.75 0.11 M VH VL 12.70 3.58 0.11 H VH VL

Cation saturation (%) 92 VH 83 VH 95 VH

Avail. P (Bray) ppm P1 31 M 25 L 4 VL

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high

Chemical activity: A high level of chemical activity is indicated by the cation exchange capacity and amount and depth of incorporation of organic matter. The soil is expected to retain plant nutrients against leaching losses. Nitrogen: The release of available nitrogen is expected to be low to medium caused by a long history of agricultural usage of this soil; additional nitrogen as fertilizer would be essential in crop production. Phosphorus: Surface values are high due to current fertilization; as with potassium, movement into the deeper soil is retarded; levels are indicative of a fertile soil. Potassium: The surface layer had a high value due to fertilizer use; on this chemically active soil, potassium is leached to the subsoil only very slowly. Magnesium: Relative to the other cations, values are very high and this is sustained with depth which indicates the influence of the parent material. No additions as fertilizer is necessary. Calcium: Values indicate a fertile soil and no corrective measures are needed. pH values: This is ideal for crop growth and no corrective measures are needed. Land use recommendations: This soil is fertile but steepness of slope and associated erosion hazard are impediments to agricultural use. Based on the inherent properties and associated landscape features, the land use recommendations are given below:

P2 47 H 38 M 10 VL

Slope class

Angle of slope (degrees)

Recommended crops

Minimum management practices

B C D

2-5 5-10 10-20

Banana; food and Minimum tillage; land laid out vegetable crops; on contour; grass strips; safe arrowroot; banana in disposal of water protected locations

E F

20-+30 >30

Tree crops; agro- Plant crops on contour; forestry; cultivated individual basins; limited forests access; safe disposal of water

Soil fertility maintenance: This is a naturally fertile soil but its use for agriculture is adversely affected by the steep landscape and associated erosion hazard. A fertilizer which supplies the three main nutrients nitrogen, phosphorus and potassium in roughly equal amounts is recommended for most crops. The fertilizer 13:13:21 at about 600kg/ha is recommended for banana and food and vegetable crops, applied in split dressings during the wet season. For tree crops about 200 kg/ha of the same fertilizer should be used but this should be increased as the trees mature. The fertility levels of the soil should be monitored at regular intervals and fertilizer use adjusted accordingly.

Soil no. 13

Soil name

Soil Rainfall classification (mm/yr) Fort Cindery Low Level Yellow 2250 - 2500 Gravelly Sandy Earth Weak dry Loam and Typic Tropudalfs season Gravelly Sandy Loam

Land area 644 ac 261 ha

This is a dark brown to yellowish brown gravelly loamy sand on recent volcanic ash and agglomerate. It has slightly imperfect drainage and moderately slow permeability. It occurs on landscapes below 200 m elevation; there is a steep phase with severe erosion hazard; otherwise the overall hazard is moderate.

Slope categories and land capability classes are given below: Slope class D E, F

Angle of slope (degrees) 20-30 >30

Land area (ac) (ha) 610 247 34 14

Capability classes IVe VIe

Current land use and characteristics of site and soil sampled: The sampling site was located east of Georgetown beyond the residential zone and arrowroot cultivations; the site was recently planted with banana which is the major crop in the general area. Details of the sampling are as follows: Soil depth (cm) 0-15 15-30 30-60

Sample number 19 20 21

Remarks Banana cultivation well maintained, some irrigation used.

Soil fertility assessment: The soil analytical results for fertility assessment are given below: Sample depth (cm)

Organic matter %

ENR (kg/ha)

CEC cmol/kg soil

0-15

6.3

2.8

13.8

15-30

5.8

1.9

30-60

5.9

1.4

112 M 92 M 81 L

12.2 18.2

Exchangeable cations cmol/kg soil Ca Mg K 7.55 1.0 1.61 M VH VH 6.55 0.87 0.56 M VH VH 9.75 4.33 1.0 M VH VH

Cation saturation (%) 76 H 65 M 83 VH

Avail. P (Bray) ppm P1 63 VH 21 L 8 L

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high

Chemical activity: There is a satisfactory level of chemical activity as indicated by the cation exchange capacity values and amount and penetrating of organic matter. The soil is expected to retain nutrients applied as fertilizer. Nitrogen: A very good level of release of nitrogen is expected - due to the relatively high amounts of organic matter. Phosphorus: Very high amounts in the surface layer is probably due to recent fertilization of the newly planted banana crop. In any event, the soil seemed well supplied with this nutrient.

P2 79 VH 36 M 15 L

Potassium: Very high levels were obtained with a concentration in the surface layer probably due to recent fertilization. Crops growing on this soil seemed amply supplied with this nutrient. Magnesium: Relative to the other cations, magnesium levels are very high, indicating that there is no need for supplementation. Calcium: Adequate amounts present and balance with the other cations is good; no corrective measures are needed. pH values: This is ideal for good crop growth and no adjustments are needed. Land use recommendations: Based on the inherent properties of the soil, associated landscapes and the present fertility status, the land use recommendations are given below: Slope Angle of Recommended crops Minimum management class slope practices (degrees) D

20-30

Banana, arrowroot, Minimum tillage; land laid out ginger, tumeric, sweet on the contour; grass strips; potato; aroids run-off drains

E-F

>30

Tree crops and agro- Controlled access; minimum forestry land clearing and tillage; individual basins

Soil fertility maintenance: Only maintenance levels of fertilization are needed since the overall fertility level of the soil is already high. A dressing of 500 - 600 kg/ha of 13:13:21 alternating every other year with 20;10:10 seems adequate for the banana crop; for other crops, 300 â&#x20AC;&#x201C; 400 kg/ha should be applied in split doses every 6 - 8 weeks during the wet season.

Soil no. 14

Soil name Akers Loam

Soil Rainfall classification (mm/yr) Sandy Low Level Yellow 1875-2125 Earth marked dry Typic Argiustolls season

Land area 729 ac 295 ha

This is a dark brown to dark yellowish brown sandy loam on tuff with good drainage and permeability. It occurs on landscapes with less than 200 m in elevation on gentle to moderate slopes. There is normally only slight erosion hazard. Slope categories and capability classes Slope class Angle of slope (degrees) B 2-5 B-C 2-10 D 10-20

are given below: Land area (ac) (ha) 280 113 364 147 85 34

Capability classes I IIe IIIe

Current land use and characteristics of soil sampled: The site was located near Argyle which is a traditional peanut and food crop producing area; at sampling, some banana and peanut were cultivated but the sampling location was occupied with a crop of pigeon pea which was very weedy. The sampling details are given below: Soil depth (cm) Sample number 0-15 37 15-30 38 30-60 39

Remarks Soil fairly dry and subsurface horizon fairly compact

Soil fertility assessment: The three Akers soil i.e Akers sandy loam, Akers sandy clay loam and Akers clay loam and are closely related soils and occur within the same agro-ecological zone and have similar crop suitability. Because of this, the soil fertility assessment, land use recommendations and soil fertility maintenance will be considered together with the last named soil.

Soil no. 15

Soil name

Soil Rainfall classification (mm/yr) Akers Sandy Clay Low Level Yellow 1875 - 2125 Loam Earth Marked dry season

Land area 1588 ac 643 ha

This is a very dark brown to dark yellowish brown sandy clay loam on tuff and having good drainage and moderate permeability. There are no stones and none to slight erosion hazard. It occurs on landscapes below 200 m elevation and the relief varies from gentle to steep. Slope categories and land capability classes are given below: Slope class Angle of slope Land area Capability (degrees) (ac) (ha) classes B 2-5 8 3 I C 5-10 209 85 IIe D 10-20 895 362 IIIe D 10-20 472 191 IVe Current land use and characteristics of site sampled: The site was located on the road to Rivulet at the McCarthy Village Junction about 300 m from the actual junction. It was part of a recently abandoned sweet potato cultivation and had slope of about 15Ë&#x161; - 20Ë&#x161;. Details of the sampling are given below: Soil depth (cm) Sample number 0-15 49 15-30 50 30-60 51

Remarks Soil fairly dry with strong dark brown to brown colour

Soil fertility assessment: The three Akers soils i.e. Akers sandy loam, Akers sandy clay loam and Akers clay loam and clay are closely related soil and occur within the same agro-ecological zone; they also have similar crop suitability. Because of this, the Soil fertility assessment, Land use recommendation and Soil fertility maintenance will be considered with the last named soil.

Soil no. 16

Soil name

Soil Rainfall classification (mm/yr) Akers Clay Loam Low Level Yellow 1875-2125 and Clay Earth Marked dry Typic Haplustalfs season

Land area 1232 ac 499 ha

This is a dark brown to dark yellowish brown friable clay loam on tuff with slightly imperfect drainage and moderate permeability. It occurs on landscapes under 200m in elevation on gentle to moderately steep land. Normally the erosion hazard in annual cropping is severe. There is some deterioration in physical condition with continuous cultivation of annual crops. There are some rock outcrops. Slope categories and capability classes Slope class Angle of slope (degrees) D 10-20 D-E 10-30 E-F >30

are given below: Land area (ac) (ha) 231 94 926 375 19 8

Capability classes IIIe IVe VIe

Current land use and characteristics of site sampled: The sampled site was located near New Adelphi in good banana cultivation. Banana and food crops are the main crops grown on the soil. Details of the sampling are given below: Soil depth (cm) Sample number 0-15 31 15-30 32 30-60 33

Remarks Fairly compact at 1560cm; increase in gravel content at depth

Soil fertility assessment: The Akers family of soils i.e. Akers Sandy Loam, Akers Sandy Clay Loam and Akers Clay Loam and Clay are closely related, the main difference being the texture of the surface layer. The analytical results show close similarity and they occur within the same agro-ecological zone. For these reasons they will be considered as a group for Fertility assessment, Land use recommendations and Fertility maintenance. The analytical results for the three soils are given below:

Soil Number 14 - Akers Sandy Loam Sample depth (cm)

Organic matter %

ENR (kg/ha)

CEC cmol/kg soil

0.15

6.2

1.9

19.4

15-30

6.5

1.1

30-60

6.7

1.3

92 M 74 L 78 L

15.5 12.4

Exchangeable cations cmol/kg soil Ca Mg K 10.25 6.08 0.72 M VH VH 8.05 6.08 0.29 M VH M 7.70 4.00 0.06 M VH VL

Cation saturation (%) 87 VH 93 VH 95 VH

Avail. P (Bray) ppm P1 2 VL 2 VL 2 VL

P2 3 VL 3 VL 4 VL

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high Soil Number 15 - Akers Sandy Clay Loam Sample depth (cm)

Organic matter %

0.15

6.0

1.8

15-30

6.4

1.8

30-60

6.5

1.9

ENR (kg/ha)

90 M 90 M 76 L

CEC cmol/kg soil 20.4 23.8 22.9

Exchangeable cations cmol/kg soil Ca Mg K 12.6 4.17 0.62 M VH VH 16.25 4.75 0.21 H VH VL 16.05 5.17 0.02 H VH VL

Cation saturation (%) 85 VH 89 VH 93 VH

Avail. P (Bray) ppm P1 1 VL 1 VL 1 VL

P2 2 VL 3 VL 3 VL

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high Soil Number 16 - Akers Clay Loam and Clay Sample depth (cm)

Organic matter %

ENR (kg/ha)

CEC cmol/kg soil

0.15

6.1

2.0

21.1

15-30

6.4

2.0

30-60

6.5

1.1

94 M 94 M 76 L

18.4 14.4

Exchangeable cations cmol/kg soil Ca Mg K 11.3 6.0 0.90 M VH VH 9.45 5.67 1.28 L VH VH 8.00 3.75 1.62 M VH VL

Cation saturation (%) 86 VH 89 VH 93 VH

Avail. P (Bray) ppm P1 29 M 16 L 2 VL

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high

Chemical activity: These soils have a high level of chemical activity compared to other St. Vincent soils as indicated by the cation exchange capacity values which is maintained at all depths. The satisfactory level and depth of penetration of organic mater is a contributory factor.

P2 39 M 26 M 5 VL

Nitrogen: Nitrogen release from soil reserves is expected to be low to medium and therefore nitrogen fertilization would be essential in good crop production. Phosphorus: The available phosphorus levels show the clear influence of the banana crop and associated traditional high level of fertilization. Soils 14 and 15 were cultivated with food crops while soil 16 had a good banana crop and may have had good banana cultivation for a continuously long period. This is reflected in a medium level of available phosphate for this soil, but low and very low levels for soils 14 and 15. It is therefore possible to build up the level of available phosphate in these soils through fertilizer use. Potassium: The available potassium levels also shows the influence of previous fertilizer use on availability. Soil No. 16 has very high values at all depths while soil 14 and 15 had high values only in the surface layer. Residual effects of fertilizers used in the past could have been a contributory factor. Magnesium: Exchangeable magnesium is very high in the three soils at all depths; this was due to the influence of the parent materials; no additions are needed from fertilizers. Calcium: Medium to high levels occur in the soils which indicates no corrective measures are needed. pH value: This is ideal for plant growth and the high values are reflected by the high cation saturation. On the whole the Akers family of soils are fertile soils which can be managed for high production levels. Land use recommendations: The Akers soils have high capability rating and can be used for any crop which can be grown in St. Vincent. For banana and plantain, supplemental irrigation and/or soil water conservation should be practised; crops such as arrowroot, peanut and sweet potato and other food and vegetable crops can be produced without irrigation. Some protection with windbreaks may be beneficial in exposed areas. Soil fertility maintenance: A fertilizer supplying roughly equal amounts of nitrogen, phosphorus and potassium but no magnesium is recommended. The closest match is 13:13:21 which should be applied at about 500-600 kg/ha for banana and plantain and at 300-400 kg/ha for other crops, applied in split applications at four to six weekly intervals during the active growing period of the crops are recommended.

Soil no. 17

Soil name

Soil Rainfall classification (mm/yr) Penniston Loam Low Level Yellow 2250 - 2500 and Clay Loam Earth Weak dry Typic Tropudalfs season

Land area 473 ac 191 ha

This is a dark brown to dark yellowish brown friable loam on tuff with good drainage and moderate permeability. It occurs on landscapes below 200 m elevation and there is a moderate erosion hazard. Typically the soil developed at the base of steep cliffs on the west side of the island and is often over old river terraces. Slope categories and capability classes Slope class Angle of slope (degrees) C 5-10 C 5-10 D 10-20

are given below: Land area (ac) (ha) 212 86 129 52 129 52

Capability classes IIe IIIb IIIe

Current land use and characteristics of site sampled: The site was located near Queensbury in the Buccament Valley in the vicinity of a church and had a 2 - 3 month old plantain crop which appeared in good condition, but weedy; other crops in the area included banana and aroids. Details of the sampling are given below: Soil depth (cm) Sample number 0-15 75 15-30 76 30-60 77

Remarks Soil very friable up to 30cm, below which was the parent material

Soil fertility assessment: The analytical results for the soil are given below: Sample depth (cm)

Organic matter %

ENR (kg/ha)

CEC cmol/kg soil

0-15

6.0 M 6.0 M 6.3 M

2.9

114 M 92 M 81 L

11.0

15-30 30-60

1.9 1.4

10.3 9.9

Exchangeable cations cmol/kg soil Ca Mg K 6.40 2.50 0.53 M VH VH 6.10 2.00 0.60 M VH VH 6.45 1.67 0.74 H VH VH

Cation Saturation (%) 86 VH 84 VH 89 VH

Avail. P (Bray) ppm P1 4 VL 3 VL 2 VL

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high

P2 5 VL 4 VL 3 VL

Chemical activity: An acceptable level of chemical activity is indicated by the cation exchange capacity and amount and penetration of organic matter. The soil will retain nutrients applied as fertilizers and there is no danger of excessive leaching. Nitrogen: The estimated nitrogen release is satisfactory; the indication is that a significant amount of the nitrogen needed for production of a crop can be contributed from the soil reserves. Phosphorus: Low levels of available phosphorus were obtained which could indicate that the area was in fallow for a period of time and only recently was cultivated with plantain. There was therefore no residual effect from recent use of fertilizers. Potassium: Very high levels of exchangeable potassium were obtained which was inherited from the soil parent materials. Magnesium: Very high levels of exchangeable magnesium were obtained which was inherited from the soil parent materials. Calcium: Medium to high levels of exchangeable calcium exists in the soil and this was inherited from the soil parent material. No corrective measures are needed, pH value: The levels obtained are ideal for crop production and no corrective measures are needed. Land use recommendations: This soil is well suited to banana and food and vegetable crops which are already being grown in the area. It has high capability; however, use should centre around control of soil erosion with measures such as minimum tillage, grass strips, planting on ridges, run-off drains, and for banana and plantain, use of individual basins for crop planting. When boulders are present, banana and plantain would be more suited. For banana and plantain, a mixed fertilizer supplying roughly equal amounts of nitrogen, phosphorus and potassium such as 13:13:21 is recommended at a moderate rate of 500 - 600 kg/ha applied in split applications during the growing season. For other crops, the rates should be reduced to 300 â&#x20AC;&#x201C; 400 kg/ha. The need for addition of magnesium is not indicated.

Soil no. 18

Soil name

Soil Rainfall classification (mm/yr) Bellevue Loam Low Level Yellow 1875-2125 and Clay Loam Earth Marked dry Typic Tropudalfs season

Land area 958 ac 388 ha

This is a dark brown friable loam on tuff with good drainage and moderate permeability. It occurs in landscapes below 200 mm elevation in foothill areas and have normal relief. There is a moderate erosion hazard. Slope categories and capability classes Slope class Angle of slope (degrees) D 10-20 D-E 10-30

are given: Land area (ac) (ha) 199 81 777 315

Capability classes IIIe IVe

Current land use and characteristics of site sampled: The site was located near Park Hill in the Colonarie District on about 20Ë&#x161; slope. It was in banana cultivation which may have been fertilized about four weeks previously. Apart from banana which was the main crop in the area, plantain and other food crops were being grown. Details of the sampling are given below: Soil depth (cm) Sample number 0-15 157 15-30 158 30-60 159

Remarks Soil fairly dry in the surface but wetter at depth.

Soil fertility assessment: The Soil fertility assessment, Land Use recommendations and Soil fertility maintenance are given with soils 19 and 20 with which this soil is closely related and occurs in the same agro-ecological zone.

Soil no. 19

Soil name Bellevue Loam

Soil Rainfall classification (mm/yr) Sandy Low Level Yellow 1875-2125 Earth Marked dry Typic Eutropepts season

Land area 563 ac 228 ha

This is a friable, dark brown to dark yellowish brown sandy loam on tuff with good drainage and moderate permeability. It occurs in elevations lower than 200m in foothill locations and have gentle slopes. There is only a slight erosion hazard. The slope categories and capability classes are given below: Slope class Angle of slope Land area (degrees) (ac) (ha) B 2-5 41 17 C 5-10 468 190 D 10-20 23 9 E 20-30 31 13

Capability classes I IIe IIIe IVe

Current land use and characteristics of site sampled: The site was located on the road to Chapmans through good banana cultivation; the site itself had a good banana crop and about 20Ë&#x161; slope. Details of the sampling are given below: Soil depth (cm) Sample number 0-15 28 15-30 29 30-60 30

Remarks All through the area there was intensive banana cultivation

The Soil fertility assessment, Land use recommendation and Soil fertility maintenance are given together with soils 19 â&#x20AC;&#x201C; 21; this soil belongs to the Bellevue family of soils which are all closely related and occurs in the same agro-ecological zone.

Soil no. 20

Soil name

Soil Rainfall classification (mm/yr) Bellevue Low Level Yellow 1875-2125 Gravelly Sandy Earth Marked dry Loam Typic Eutropepts season

Land area 527 ac 213 ha

This is a friable dark brown to dark yellowish brown gravelly sandy loam on tuff with good drainage and moderate permeability. It occurs in elevations below 200m elevation on hillsides with normal relief. There is considerable erosion hazard. The soil is free of stones and boulders. 60

Slope category and capability class are given below: Slope class Angle of slope Land area (degrees) (ac) (ha) E 20-30 527 213

Capability classes IVe

Current land use and characteristics of site: The site was located east of the cacao factory in the Mount William District on a banana cultivation owned by Mr. De Freitas; the entire area was in banana which was cultivated intensively. Details of the sampling are given below: Soil depth (cm) Sample number 0-15 16 15-30 17 30-60 18

Remarks Intensive banana cultivation; good farm road through the area

The Soil fertility assessment, Land use recommendations and Soil fertility maintenance are all given together with soils 19 â&#x20AC;&#x201C; 21; the Bellevue soils are closely related and occur in the same agro-ecological zone; hence they can be considered together.

Soil no. 21

Soil name

Soil Rainfall classification (mm/yr) Bellevue Gravelly Low Level Yellow 1725-2125 Loamy Sand Earth Marked dry (alluvialTypic Eutropepts season colluvial variant)

Land area 167 ac 68 ha

This is a dark brown to very dark grey brown gravelly loamy sand on colluvium (valley in-fill) with good drainage and rapid permeability. It occurs below 200 m elevation on gentle slopes and has no stones or boulders. On the whole the soil has a moderate erosion hazard for annual cropping. The slope category and capability class are given below: Slope class Angle of slope Land area (ac) (degrees) B 2-5 167

Capability classes IIe

Current land use and characteristics of site: The site was located along a road about 3.2 km from Byera through good banana cultivation. The slope at the site was about 5Ë&#x161;. 61

Details of the sampling are given below: Soil depth (cm) Sample number 0-15 25 15-30 26 30-60 27

Remarks Entire area in continuous banana cultivation with no irrigation

Soil fertility assessment: The Bellevue soils i.e. Bellevue Loam and Clay Loam, Bellevue Sandy Loam, Bellevue Gravelly Loamy Sand (alluvial - colluvial variant) are closely related, and like the Akers soils, their main difference being in the texture of the surface layer. The analytical results show close similarity and they occur within the same agroecological zone. For these reasons, they were considered as a group for Fertility assessment, Land use recommendations and Fertility maintenance. The analytical results for the three soils are given below: Soil No. 18 Bellevue Loam and Clay Loam Sample depth (cm)

Organic matter %

ENR (kg/ha)

CEC cmol/kg soil

0-15

1.6

30-60

6.6

1.9

85 M 87 M 92 M

13.5

15-30

7.1 M 6.7

1.7

12.7 14.7

Exchangeable cations cmol/kg soil Ca Mg K 10.0 2.0 1.49 H VH VH 9.16 1.92 1.00 H VH VH 11.2 2.0 0.56 H VH VH

Cation saturation (%) 100 VH 95 VH 94 VH

Avail. P (Bray) ppm P1 27 M 13 L 5 VL

P2 43 H 17 L 7 VL

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high Soil No. 19 Bellevue Sandy Loam Sample depth (cm)

Organic matter %

ENR (kg/ha)

CEC cmol/kg soil

0-15

3.1

30-60

6.4

109

119 H 94 M 92 M

7.9

15-30

6.2 M 6.3

2.0

7.0 11.0

Exchangeable cations cmol/kg soil Ca Mg K 4.45 1.45 1.0 M VH VH 4.40 1.07 0.82 H VH 7.00 1.51 1.49 H VH VH

Cation saturation (%) 87 VH 90 VH 91 VH

Avail. P (Bray) ppm P1 66 VH 25 L 3 VL

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high

P2 103 VH 37 M 9 VL

Soil No. 20 Bellevue Gravelly Sandy Loam Sample depth (cm)

Organic matter %

ENR (kg/ha)

CEC cmol/kg soil

0-15

7.4

2.1

8.9

15-30

7.1

1.7

30-60

6.9

1.6

92 M 96 M 87 M

11.0 8.8

Exchangeable cations cmol/kg soil Ca Mg K 6.40 1.63 0.87 H VH VH 9.55 1.27 0.16 VH H L 7.00 1.28 0.39 VH VH VH

Cation saturation (%) 100 VH 100 VH 99 VH

Avail. P (Bray) ppm P1 30 M 5 VL 13 L

P2 48 H 13 L 23 L

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high Soil No. 21 Bellevue Gravelly Loamy Sand (alluvial-colluvial variant) Sample depth (cm) 0-15 15-30 30-60

6.0 M 6.3 M 6.6 H

Organic matter % 2.9 1.9 1.2

ENR (kg/ha)

114 M 92 M 76 L

CEC cmol/kg soil 9.0 8.7 9.8

Exchangeable cations cmol/kg soil Ca Mg K 5.35 1.62 0.60 M VH VH 5.65 1.49 0.64 H VH VH 7.15 0.69 0.69 H VH VH

Cation saturation (%) 90 VH 87 VH 94 VH

Avail. P (Bray) ppm P1 101 VH 57 VH 11 L

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high

Chemical Activity: There is a good level of chemical activity considering the fairly coarse texture of the soils; this is due to the presence of clay minerals of high activity and a high level of organic matter with good penetration with depth. The soils will retain nutrients applied as fertilizers. Nitrogen: The estimated nitrogen release for these soils range from medium to high which indicates an ability to supply a substantial amount of the nutrient needed by crops from their reserves. Only supplemental nitrogen is therefore needed. Phosphorus: Due to current high levels of fertilizer use associated with the banana crop which is widely cultivated on these soils, the levels of available phosphorus is very high to high up to 30cm depth; lower than this, the values decrease which is expected. Future use of phosphate fertilizers should take into account the present high levels in the soils. Potassium: The levels of exchangeable potassium range from high to very high and this is sustained with depth. This is due to high soil reserves as well as continuous use of fertilizers high in the nutrient.

P2 169 VH 80 VH 14 L

Magnesium: Very high values for exchangeable magnesium were obtained at all depths which indicate the influence of the parent material. Continuous use of magnesium containing fertilizers has contributed to these high levels. Calcium: Exchangeable calcium ranges from medium to very high; there is a satisfactory level of calcium saturation and no corrective measures are needed. pH value: Ideal values were obtained throughout which were in accordance with the high cation saturation of the soils. No corrective measures are needed. Land use recommendations: Among the St. Vincent soils, the Bellevue soils have high capability rating and this underlies their general suitability for crop production. The banana crop which is now widely grown can benefit from dry season supplemental irrigation and some protection from winds in the more exposed locations. The same would apply to plantain. Other crops with shorter vegetative growth such as arrowroot, sweet potato and peanut are also appropriate. On the steeper lands, advantage can be taken of the rainfall distribution to produce fruit such as mango, avocado, sugar and custard apple. Citrus may also be suitable. In using the Bellevue soils it must be appreciated that there is an erosion hazard and therefore simple anti-erosion measures such as contour planting, grass strips, run-off drains and individual basins should be used where possible and appropriate. Soil fertility maintenance: The current high level of fertility of these soils must be appreciated in fertilizer use to avoid creating imbalance among the various nutrients. For the present, additions of magnesium are not needed and maintenance amounts of nitrogen, phosphorus and potassium should be used. For banana and plantain 500 â&#x20AC;&#x201C; 600 kg of 13:13:21 should be applied in split applications during the year and for other crops, a rate of about 400 kg/ha/yr in split applications is recommended; these recommendations should be continuously re-assessed based on soil analysis results.

Soil no. 22

Soil name

Soil Rainfall classification (mm/yr) Gabriel Sandy Low Level Yellow 1725 - 2125 Loam and Sandy Earth Marked dry Clay Loam Typic Eutropepts season

Land area 664 ac 268 ha

This is a friable very dark grey brown to dark brown sandy loam with some gravel developed on tuff; the soil has good drainage and moderate permeability. It occurs on landscapes below 200 m in elevation on gently and rolling topography. There is a moderate erosion hazard. The slope categories and capability classes are given below: Slope class Angle of slope Land area (degrees) (ac) (ha) C 5-10 373 151 D 10-20 45 18 D 10-20 23 9 D-E 10-30 223 90

Capability classes IIe IIIe IVb IVe

Current land use and characteristics of site sampled: The site was located at Petersâ&#x20AC;&#x2122; Hope Estate with mature coconut over-grown with weeds; the slope was about 15Ë&#x161;. The coconut cultivation was semi-abandoned for a long time. Details of the sampling are given below: Soil depth (cm) Sample number 0-15 81 15-30 82 30-60 83

Remarks This is a Government owned estate: coconut cultivation not being maintained; however, nuts are being regularly harvested by copra processors in the area

Soil fertility assessment: Gabriel sandy loam and sandy clay loam and Gabriel loamy sand (alluvial-colluvial variant) are closely related soils and they occur in the same agro-ecological zone; they have similar capability and management requirements. For these reasons they are considered together with respect to Soil fertility assessment, Land use recommendation sand Soil fertility maintenance.

Soil no. 23

Soil name

Soil Rainfall classification (mm/yr) Gabriel Loamy Low Level Yellow 75 - 85 Sand (alluvial â&#x20AC;&#x201C; Earth Marked dry colluvial variant) Typic Tropudolls season

Land area 38 ac 15 ha

This is a friable dark brown to dark yellowish brown loamy sand with common small stone fragments developed on alluvium. The soil has good drainage with rapid permeability and none to slight erosion hazard. It occurs on landscapes with elevation under 60 m on gentle to flat relief. The slope categories and capability classes are given below: Slope class Angle of slope Land area (degrees) (ac) (ha) A 0-2 26 11 B 5-10 9 4

Capability classes I IIe

Current land use and characteristics of the site sampled: The site was located near Keartons along the road into the village. It was supporting mixed crops of maize, sorrel, ochro and plantain; banana was also cultivated in the area with irrigation; the slope was about 5Ë&#x161;. Details of the sampling are given below: Soil depth (cm) Sample number 0-15 84 15-30 85 30-60 86

Remarks Mixed food and vegetable cropping was the main usage. Small cultivations of banana were also seen.

Soil fertility assessment: The Gabriel Sandy Loam and Loamy Sand soils are closely related, the main differences being the texture of the surface layer. The analytical results show close similarity and they occur within the same agro-ecological zone. For these reasons they would be considered together for their Fertility assessment, Land use recommendations and Fertility maintenance.

The analytical results for the two soils are given below: Soil No. 22 - Gabriel Sandy Loam and Sandy Clay Loam Sample depth (cm)

Organic matter %

ENR (kg/ha)

CEC cmol/kg soil

0-15

6.2 M 6.3 M 6.6 H

2.8

112 M 90 M 90 M

15.3

15-30 30-60

1.8 1.8

15.8 18.6

Exchangeable cations cmol/kg soil Ca Mg K 9.75 2.83 0.90 M VH VH 10.40 3.08 0.72 H VH VH 13.35 3.67 0.49 H VH H

Cation saturation (%) 88 VH 90 VH 94 VH

Avail. P (Bray) ppm P1 8 VL 5 VL 3 VL

P2 13 L 22 L 7 VL

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high Soil No. 23 - Gabriel Loamy Sand (alluvial - colluvial variant) Sample depth (cm)

Organic matter %

ENR (kg/ha)

CEC cmol/kg soil

0-15

6.2 M 6.3 M 6.4 M

2.5

105 M 92 M 90 M

15.8

15-30 30-60

1.9 1.8

15.2 15.7

Exchangeable cations cmol/kg soil Ca Mg K 10.5 2.67 0.44 H VH H 10.35 2.75 0.47 H VH H 10.55 2.75 0.69 H VH VH

Cation saturation (%) 86 VH 89 VH 89 VH

Avail. P (Bray) ppm P1 29 M 18 L

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high

Chemical activity: Considering that 65 percent of these soils consist of sand size particles, the finer fraction show a high degree of chemical activity. The amount and depth of penetration of organic matter also contributes to this. The soils are therefore expected to retain nutrients added as fertilizers. Nitrogen: A good (medium) level of nitrogen can be released by these soils to support crop production. Therefore only supplemental nitrogen would be needed as fertilizer. Phosphorus: Available phosphorus levels are very low for soil No. 22 (Gabriel sandy loam to sandy clay loam); clearly, the derelict coconut cultivation did not receive any fertilizer for a long time and the measured available phosphate was only from the soil reserves. The Gabriel Loamy Sand on the other hand had medium levels of available phosphorus which indicated that some fertilizer was being used on the mixed food and vegetable crops under planted within the main plantain crop. Phosphate fertilization would be necessary on these soils for good crop yields.

P2 40 M 26 M

Potassium: High values of exchangeable potassium was obtained for both soils at all depths indicating a good amount of reserves in the soil parent material. Only maintenance fertilizer use is recommended. Magnesium: Very high values were obtained throughout which indicates a good reserve in the soils and therefore no need for magnesium fertilizers. Calcium: High to medium levels were obtained and there is no need for supplementation. The high cation saturation and pH values support this conclusion. Land use recommendations: The diversity of agricultural production on this soil is limited by environmental conditions such as the total rainfall and its distribution and accessibility in addition to other soil factors. A severe dry season in the absence of supplemental irrigation would mean that agro-ecological conditions would limit the selection of crops. There could always be a risk in producing plantain and banana although in protected areas and in situations where moisture conservation is practised it may be successful. The obvious selections are food and vegetable crops i.e. aroids, sweet potato, yam, ginger and cassava. Grain legumes and hardy vegetables can also be produced. The production of fruit such as mango, citrus, avocado and spices may also be possible. Use of soil conservation measures such as terraces, grass strips, planting on the contour and use of individual basis for perennial crops are strongly recommended. Soil fertility maintenance: Nitrogen and phosphorus are needed for good production. Additions of magnesium and lime are not needed at this time. A fertilizer such as 13:13:21 at about 300 400 kg/ha applied in split applications during the active growing period for annual crops is recommended. For perennial crops, the same fertilizer may be applied on a per tree basis of about 0.5 kg to 2 kg/tree but split over about 4 - 6 applications each year. For banana and plantain, 500 â&#x20AC;&#x201C; 600 kg/ha/yr applied in splits should give good results.

Soil no. 24

Soil name

Soil Rainfall classification (mm/yr) Belmont Gravelly Low Level Yellow 1785-2125 Sandy Loam Earth Marked dry Typic Tropudolls season

Land area 1127 ac 455 ha

This is a friable very dark grey brown to dark brown gravelly sandy loam on tuff. It has good drainage and moderate permeability and occurs on landscapes below 200m elevation on gentle to steep slopes. There is a steep phase and on the whole a severe erosion hazard under continuous cropping exists, particularly gullying. Slope categories and capacity classes are given below: Slope class Angle of slope Land area (degrees) (ac) (ha) C 5-10 68 28 C 5-10 26 11 D 10-20 18 7 D-E 10-30 25 10 D-E 10-30 856 347 E 20-30 134 54

Capability classes IIe IIIs IIIe IVe Ve VIe

Current land use and characteristics of site sampled: The site was located near Rosehall in the holding of Angela Ferdinand; it was formerly cultivated with carrot but the land was being prepared for aroids from temporary fallow at the time of sampling. The slope was about 12Ë&#x161; - 15Ë&#x161;. Some banana was being produced in the area but aroids were prominent. Details of the sampling are given below: Soil depth (cm) Sample number 0-15 90 15-30 91 30-60 92

Remarks Carrot did not seem to be a popular crop in the area any longer; sweet potato and aroids are presently more important

Soil fertility assessment: The Belmont soils i.e. Belmont sandy loam and Belmont gravelly sandy loam (alluvial/colluvial variant) are closely related. The analytical results show close similarity and they occur in the same agro-ecological zone. For these reasons, they will be considered together for Soil fertility assessment, Land use recommendations and Soil fertility maintenance. 69

Soil no. 25

Soil name Belmont Gravelly Sandy Loam (alluvialcolluvial variant)

Soil Rainfall classification (mm/yr) Low Level Yellow 1725 - 2125 Earth Marked dry Cumulic Tropudolls season

Land area 120 ac 48 ha

This is a friable dark brown gravelly sandy loam on volcanic ash and tuff with somewhat excessive drainage and rapid permeability; it has frequent small stone fragments. It occurs on landscapes under 60 m in elevation on gentle to flat relief and has little to moderate erosion hazard. Gullying caused by drainage from higher elevations is the main erosion feature. Slope categories and capability classes Slope class Angle of slope (degrees) A 0-2 C 5-10

are given below: Land area (ac) (ha) 45 18 75 30

Capability classes I IIe

Current land use and characteristics of the site sampled: The site was located near Fitz-Hughes in a banana cultivation owned by Edgar Jordan. A high level of husbandry was being practised with a weed-free field. The slope was about 10Ë&#x161;. Details of the sampling are given below: Soil depth (cm) Sample number 0-15 93 15-30 94 30-60 95

Remarks Banana production was the main land use in the area

The Belmont Gravelly Sandy Loam and the Belmont Gravelly Sand Loam (alluvialcolluvial variant) are closely related, the main difference being that the former occurs on a wider range of slopes. The analytical results show close similarity and they occur within the same agro-ecological zone. The alluvial-colluvial variant has less sand. For these reasons they would be considered together for Fertility assessment, Land use recommendation and Fertility maintenance.

The analytical results for the two soils are given below: Soil No. 24 - Belmont Gravelly Sandy Loam Sample depth (cm)

Organic matter %

ENR (kg/ha)

CEC cmol/kg soil

0-15

5.8

3.5

8.9

15-30

5.8

3.3

30-60

6.1

1.2

128 H 123 H 76 L

8.6 11.6

Exchangeable cations cmol/kg soil Ca 5.15 M 5.45 M 8.35 H

Mg 1.17 H 0.92 M 0.83 L

K 0.95 VH 0.64 VH 0.79 VH

Cation saturation (%)

82 VH 82 VH 86 VH

Avail. P (Bray) ppm P1 2 VL 3 VL 15 L

P2 7 VL 4 VL 83 VH

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high Soil No. 25 - Belmont Gravelly Sandy Loam (alluvial - colluvial variant) Sample depth (cm)

Organic matter %

ENR (kg/ha)

CEC cmol/kg soil

0-15

6.1

1.8

15.3

15-30

6.2

1.5

30-60

6.3

1.1

80 M 74 L 66 L

16.7 13.8

Exchangeable cations cmol/kg soil Ca Mg K 10.75 1.83 0.61 H H VH 11.95 2.08 0.65 H VH VH 9.95 1.5 0.92 H H VH

Cation saturation (%) 86 VH 88 VH 90 VH

Avail. P (Bray) ppm P1 9 VL 3 VL 3 VL

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high

Chemical activity: There is a good level of chemical activity especially considering that about 65 percent of the soils is sand. The amount and deep penetration of organic matter is a contributory factor. The soils are expected to retain nutrients applied as fertilizers. Nitrogen: The estimated nitrogen release indicates a good ability of the soils to supply the nutrient from reserves but supplementation by fertilizers would be needed. Soil 24 with a higher organic matter content has a higher capacity for nitrogen release. Phosphorus: Both soils have low levels of available phosphorus but soil no. 24 has marginally higher values. The low levels for soil no. 25 would be associated with the somewhat stunted growth of the banana crop and the production of medium-sized bunches and fingers. The need for systematic phosphate fertilization for both soils is strongly indicated.

P2 17 L 4 VL 11 VL

Potassium: Both soils have very high values for exchangeable potassium which is inherited from the soil parent material. Only maintenance levels of fertilization is required. Magnesium: Levels of exchangeable magnesium are good but not very high as for other St. Vincent soils. It would be important to maintain these at the current levels and therefore some additions are needed. Calcium: The exchangeable calcium levels are adequate and no corrective measures are needed. pH value: The levels are ideal for crop growth and no corrective measures are needed. This is corroborated by the very high values for cation saturation. Land use recommendations: These soils have high capacity for crop production but the dry season would pose some limitation if supplemental irrigation is not available. With adequate fertilizer use, banana production can be improved and food and vegetable crop can be grown also. On the steeper slopes for Soil no. 24 tree crops such as mango, avocado and citrus are recommended. Arrowroot production can be successful in some locations but there would be problems with transportation of the produce to the processing plants. Soil fertility maintenance: For these soils a fertilizer which emphasizes phosphorus but also supplies some nitrogen, potassium and magnesium such as 12:24:12:2 Mgo is recommended. For good banana production about 600 kg/ha/annum should be applied in split applications; irrigation should be used. For other crops, 400kg/ha/yr applied in split applications should give satisfactory results.

Soil no. 26

Soil name

Soil Rainfall classification (mm/yr) Myrtle Cindery Low Level Yellow 1725 - 2125 Gravelly Sandy Earth Marked dry Loam Typic Eutropepts season

Land area 746 ac 301 ha

This is a dark brown to dark yellowish brown cindery, gravelly sandy loam on tuff and volcanic ash; it has good drainage and moderate permeability and occurs at elevations below 200 m on steep to excessively steep topography; there is a severe erosion hazard.

Slope categories and capability classes Slope class Angle of slope (degrees) E 20-30 F >30

are given below: Land area (ac) (ha) 20 8 726 294

Capability classes IVe VIe

Current land use and characteristics of the site sampled: The site was located on the side of the main road between Fancy and Owia; sweet potato was recently cultivated and harvested; the samples were taken in an adjoining area in temporary fallow. Most lands in the area were not farmed but where agriculture was practised, the crops were sweet potato, arrowroot and other food crops. Details of the sampling are given below: Soil depth (cm) Sample number 0-15 4 20-50

50-60

Remarks Farmers showed great skill in ridge formation on the contour; access to the farms seemed a problem due to steepness of slope

Other aspects such as Soil fertility assessment Land use recommendations and Soil fertility maintenance are presented with soil no. 27 (Myrtle cindery gravelly sandy loam, alluvial-colluvial variant) since the two soils are closely related, have similar properties and are in the same agro-ecological zone.

Soil no. 27

Soil name

Soil Rainfall classification (mm/yr) Myrtle Cindery Low Level Yellow 1725-2125 Gravelly Sandy Earth Marked Dry Loam (alluvial - Cumulic Eutropepts season colluvial variant)

Land area 65 ac 26 ha

This is a dark brown cindery, gravelly, sandy loam on alluvium-colluvium occurring in the north of the island with recent volcanic activity. Drainage is good and permeability moderate. It is distributed typically at the foothills of steep terrain at elevations below 60 m and has gentle relief. It is subject to erosion by run-off from surrounding hills; there were some boulders.

Slope categories and capability classes Slope class Angle of slope (degrees) C 5-10 C 5-10

are given below: Land area (ac) (ha) 39 16 17 7

Capability classes IIe IIIb

Current land use and characteristics of the site sampled: The site was located just east of the comprehensive school at Fancy in a pigeon pea cultivation. Most of the area was built up but there were home gardens with mixed food and vegetable crops. The slope of the site was about 5Ë&#x161; to 8Ë&#x161;. Details of the sampling are given below: Soil depth (cm) Sample number 0-15 1 15-30 2 30-60 3

Remarks Food crops dominate in the area, particularly sweet potato

The Mrytle cindery gravelly sandy loam and the Mrytle cindery gravelly sandy loam (alluvial - colluvial variant) are very similar in behaviour, the later being derived from the erosion products of the former. They occur in the north of the island and are usually continuous on the landscape. For this reason, they would be considered together with respect to Soil fertility assessment, Land use recommendation and Soil fertility maintenance. The analytical results for the two soils are given below: Soil No. 26 - Myrtle Cindery Gravelly Sandy Loam Sample depth (cm)

Organic matter %

0-15

6.2

3.1

15-30

6.5

2.1

30-60

6.8

2.0

ENR (kg/ha)

119 H 96 M 94 M

CEC cmol/kg soil 13.4 12.3 13.6

Exchangeable cations cmol/kg soil Ca Mg K 8.05 3.25 0.54 M VH VH 8.10 2.50 0.82 M VH VH 9.70 3.00 0.54 H VH VH

Cation saturation (%) 88 VH 94 VH 97 VH

Avail. P (Bray) ppm P1 12 L 3 VL 4 VL

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high

P2 19 L 6 VL 5 VL

Soil No. 27 - Myrtle Cindery Gravelly Sandy Loam (alluvial - colluvial variant) Sample depth (cm)

Organic matter %

ENR (kg/ha)

CEC cmol/kg soil

0-15

6.3

3.8

15.5

15-30

6.3

3.5

30-60

6.4

1.0

134 H 128 H 72 L

13.0 8.8

Exchangeable cations cmol/kg soil Ca Mg K 9.58 3.50 0.53 M VH VH 8.30 2.83 0.45 H VH VH 5.95 1.75 0.29 H VH M

Cation saturation (%) 90 VH 89 VH 91 VH

Avail. P (Bray) ppm P1 35 M 53 VH 38 M

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high

Chemical activity: There is a high level of chemical activity in these soils especially considering the high sand content (over 65%) as well as the gravel content. In addition to physico-chemically active clays, the amount and depth of penetration of organic matter contributes to this favourable property. The soils are expected to retain nutrients applied as fertilizers. Nitrogen: The estimated nitrogen release varied from medium to high which indicates good ability to supply this nutrient to crops from the soil reserves. Supplementation with fertilizers would be beneficial. Phosphorus: There is an important difference in levels of available phosphorus for the two soils, the alluvial-colluvial variant having very high values which is maintained at depth. Being an alluvial soil, the entire profile is derived from the eroded top soil of Myrtle gravelly cindery sandy loam; also, being in the vicinity of households, nutrient rich discarded waste is continually being added to the soil. Potassium: Very high values for exchangeable potassium were obtained at most depths which indicates parent maternal rich in the nutrient. Only maintenance dressing would be needed. Magnesium: Very high values were obtained and no need for supplementation is needed. Calcium: Medium to high values were obtained and for the present, no corrective measures are necessary. pH values: The values are ideal for crop growth and no corrective measures are necessary. The high cation saturation for both soils is in accordance with this.

P2 82 VH 86 VH 68 VH

Land use recommendations: The present use of these soils for food crop and arrowroot production is in keeping with their capability. Arrowroot cultivation should be restricted to land with slopes less than 25Ë&#x161;. The high degree of skill shown by farmers in making and maintaining ridges along the contour should be encouraged in every way. In addition other approved and practical anti-erosion devices should be adopted. On the steeper slopes and access permitting, perennial crops is a prospect with appropriate anti-erosion measures. Soil fertility maintenance: Fertilizer use should emphasize phosphorus and nitrogen with some potassium. The blend 12:24:12 seem suitable at about 400 kg/ha for sweet potato, other food crops and arrowroot; 20:10:10 fertilizer blend at the same rate can also be used. The need for magnesium is not indicated. The fertilizer should be applied in split applications during the growing period of the crop at six to eight weekly intervals.

Soil no. 28

Soil name

Soil Rainfall classification (mm/yr) Soufriere Recent Volcanic 2125 - >2500 Cindery Gravelly Ash Weak dry Sandy Loam Typic Vitrandepts. season to continuously moist

Land area 4667 ac 1885 ha

This is a dark brown cindery gravelly sandy loam with good drainage and moderate permeability. It occurs in elevations usually below 200 m and with variable, although mostly steep relief. Its loose consistence and steep slopes induces accelerated erosion. Slope categories and capability classes Slope class Angle of slope (degrees) D 10-20 E 20-30 E 20-30

are given below: Land area (ac) (ha) 136 55 3720 1507 80 32

Capability classes IIIe Ve VIe

Current land use and characteristics of the site sampled: The site was located east of Overload along a farm road on the north bank of the Rabacca River. It had a top storey of mature coconut and a lower cultivation of banana. The coconut was not being maintained but the banana crop was well cared.

Details of sampling are given below: Soil depth (cm) Sample number 0-15 7 15-30 8 30-60 9

Remarks Unconsolidated soil and parent material; soil susceptible to gully erosion.

Other aspects such as Soil fertility assessment, Land use recommendations and Soil fertility maintenance are presented with soil no. 32. (Soufriere cindery, gravelly sandy loam and Cindery gravelly loamy sand). The soils are closely related and occur within the same agro-ecological zone.

Soil no. 29

Soil name

Soil Rainfall classification (mm/yr) Soufriere Recent Volcanic 1725-2500 Cindery Gravelly Ash Weak to Loamy Sand Typic Vitrandepts marked dry season

Land area 3018 ac 1222 ha

This is a very dark grey brown to yellowish brown cindery, gravelly, loamy sand with a hard pan over burned humic top soil which was the top soil prior to the 1902 volcanic eruption; the pan of fine sand and silt is the deposit from the first ash shower of the eruption. The soil has good drainage and rapid permeability even through the indurated layer. The soil occurs on landscapes under 200 m elevation and usually gentle slopes. There is no great erosion hazard but some damage is done by run-off along bare tracks. Slope categories and capability classes Slope class Angle of slope (degrees) A 0-2 A 0-2 A-C 0-10 C 5-10

are given below: Land area (ac) (ha) 58 23 1236 500 1361 551 363 147

Capability classes I IIb IIe IIIe

Current land use and characteristics of site sampled: The site was located east of Georgetown near a school in a field of arrowroot at about mid-growth stage; the arrowroot was the main commercial crop in the area although mixed food crops were also being cultivated.

Details of sampling are given below: Soil depth (cm) Sample number 0-15 13 15-30 14 30-60 15

Remarks Housing development is encroaching on the site and soil sampled

Other aspects such as Soil fertility assessment, Land use recommendations and Soil fertility maintenance are presented with soil no. 32 which is closely related and occur in the same agro-ecological zone.

Soil no. 30

Soil name

Soil Rainfall classification (mm/yr) Soufriere Recent Volcanic 1725-2500 Gravelly Loamy Ash Weak dry Sandy Typic Troporthents season to (excessively continuously cindery variant) moist

Land area 559 ac 226 ha

This is a dark brown to dark yellowish brown cindery gravelly loamy sand with good drainage and rapid permeability. The subsoil showed some layering due to accumulations from different volcanic ash falls but the physical behaviour of the soil is not affected by this. It occurs on landscapes below 200 m elevation on gentle slopes and there are scattered boulders. The slope categories and capability classes are given below: Slope class Angle of slope Land area (degrees) (ac) (ha) B 2-5 61 25 B 2-5 497 201

Capability classes IIIe IVb

Current land use and characteristics of site sampled: The site was located on the south side of the Rabacca River on nearly flat land. The area was intensively cultivated with food and vegetable crops and banana with irrigation; the actual site was recently replanted with banana. Details of the sampling are given below: Soil depth (cm) Sample number 0-15 10 15-30 11 30-60 12

Remarks Irrigation has made all the difference to land use on this and related soils in the Rabacca Plain. 78

Other aspects such as Soil fertility assessment, Land use recommendations and Soil fertility maintenance are presented with soil no. 32 with which this soil is closely related; they also occur in the same agro-ecological zone.

Soil no. 31

Soil name

Soil Rainfall classification (mm/yr) Soufriere Recent Volcanic 1725-2500 Cindery Gravelly Ash Weak to Loamy Sand Typic Troporthents marked dry (Scant Cindery season Variant)

This is a dark reddish brown to volcanic ash and having moderate is affected by the layered nature occurs on landscapes below 200 m

Land area 191 ac 77 ha

dark yellowish brown gravelly loam on recent drainage and rapid permeability. The drainage of the subsoil due to different ash layers. It on gentle relief.

The slope categories and capability classes are given below: Slope class Angle of slope Land area (degrees) (ac) (ha) C 5-10 60 24 C 5-10 131 53

Capability classes IIe IIIe

Other aspects such as Soil fertility assessment, Land use recommendations and Soil fertility maintenance are presented with soil no. 32 with which it is clearly related. The two soils also occur in the same agro-ecological zone.

Soil no. 32

Soil name

Soil classification Soufriere Recent Volcanic Cindery Gravelly Ash Sandy Loam and Cumulic Cindery Gravelly Vitrandepts Loamy Sand (alluvial colluvial Variant)

Rainfall (mm/yr) 1725-2500 Weak to marked dry season

Land area 47 ac 19 ha

This is a dark brown to dark yellowish brown cindery gravelly sandy loam and loamy sand on recent volcanic ash with good drainage and permeability. It occurs on landscapes below 200 m in elevation on gently sloping terrain. Slope categories and capability classes Slope class Angle of slope (degrees) B 2-5 C 5-10

are given below: Land area (ac) (ha) 10 4 37 15

Capability classes IIc IIIb

Soil fertility assessment: The five Soufriere soils are closely related having been formed on recent volcanic ash. One of the main differences is the amount of cindery and gravelly material in the solum although all of them have enough to dominate their behaviour. The soils will be considered as a group for Fertility assessment, Land use recommendations and Soil fertility maintenance. Soils 31 and 32 are minor soils and due to their inaccessibility and lack of time they were not sampled and analysed. Therefore analytical data are presented for soils 28 to 30. The analytical results for soils 28, 29 and 30 are given below: Soil no. 28 - Soufriere Cindery Gravelly Sandy Loam Sample depth (cm)

Organic matter %

ENR (kg/ha)

CEC cmol/kg soil

0-15

6.3

3.9

10.1

15-30

6.1

2.0

30-60

6.3

1.9

137 H 94 M 92 M

5.0 4.5

Exchangeable cations cmol/kg soil Ca Mg K 5.70 2.67 0.71 M VH VH 3.00 1.02 0.28 M VH H 2.65 1.04 0.34 M VH VH

Cation saturation (%) 90 VH 86 VH 95 VH

Avail. P (Bray) ppm P1 54 VH 45 H 26 M

P2 73 VH 74 VH 132 VH

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high Soil No. 29 - Soufriere Cindery Gravelly Loam Sand Sample depth (cm)

Organic matter %

ENR (kg/ha)

CEC cmol/kg soil

0-15

6.1

2.6

7.4

15-30

6.0

1.7

30-60

6.2

1.9

108 M 87 M 92 M

6.4 14.8

Exchangeable cations cmol/kg soil Ca Mg K 4.45 1.47 0.47 M VH VH 3.90 1.19 0.37 M VH VH 10.80 1.72 0.47 H H VH

Cation saturation (%) 86 VH 85 VH 88 VH

Avail. P (Bray) ppm P1 152 VH 80 VH 21 L

P2 181 VH 127 VH 40 M

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high

Soil No. 30 - Soufriere Cindery Gravelly Loamy Sand (excessively cindery variant) Sample depth (cm)

Organic matter %

ENR (kg/ha)

CEC cmol/kg soil

0-15

5.9

2.8

4.7

15-30

5.9

4.0

30-60

6.0

1.7

112 M 139 H 87 M

3.5 2.7

Exchangeable cations cmol/kg soil Ca Mg K 2.25 1.55 0.13 M VH L 1.95 0.88 0.10 M VH L 1.55 0.61 0.11 M VH L

Cation saturation (%) 84 VH 84 VH 84 VH

Avail. P (Bray) ppm P1 91 VH 78 VH 59 VH

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high

Chemical activity: Over 75 percent of the particles of these soils consists of gravelly and cindery material and therefore the chemical activity is rather low. The amount and depth of organic matter in the soils have a significant role in maintaining the level of chemical activity. Clearly they do not have the ability to retain large quantities of plant nutrients applied as fertilizers which is an important aspect in their management. Nitrogen: The estimated nitrogen release is in the medium level for all the soils which indicate the ability to provide a good amount of the nitrogen needed for crop production. Supplemental nitrogen would be required. Phosphorus: The level of available phosphorus is high to very high and this shows the influence of the fertilizer used in crop production and the inability of the soil to firmly immobilize the phosphate. In this situation, the nutrient can be lost by leaching. The levels are really too high for these particular soils and this should be taken into account in fertilizer use in the future. Potassium: The levels of exchangeable potassium again show the influence of fertilizer use. Soils no. 28 and 29 were being cropped and therefore receiving fertilizer at the time of sampling. Consequently, high values were obtained. Soil no. 30 was recently planted with banana and most likely even the initial application of fertilizers had not yet been made. Consequently, the values were low. Magnesium: Compared to the levels of the other exchangeable cations, magnesium was very high in all the soils and this was sustained at depth. The inference is that the parent material, in weathering, supply enough to the soil to support plant growth but this needs to be monitored continually.

P2 123 VH 129 VH 97 VH

Calcium: Medium levels of exchangeable calcium were obtained without any additions of the element in soil amendments. The inference is that this level of supply of the nutrient will be maintained from soil reserves. pH value: The pH values are at a good level for successful crop production and no corrective measures are needed. The high degree of cation saturation is in accordance with the level of soil pH. Land use recommendations: The potential for crop production of these soils can be easily underestimated due to their gravel content. They have been used up to the present for the production of a range of annual and perennial crops such as sugarcane, arrowroot, banana, plantain and coconut. Large areas were in coconut production but although the trees are still standing, the cultivations are not maintained. However, experience with coconut can be extrapolated to other tree crops such as mango, citrus and avocado. These soils can also be the main arrowroot producing soils in the country and their capacity to produce food and vegetable crops once irrigation is available has been well demonstrated. Their productivity can be further improved by the establishment of effective windbreaks in exposed areas where direct sea breezes are adversely affecting the banana and plantain crops for instance. The water supplying capacity of these soils can be underestimated due to their gravel content. However, the mulching effect of a surface coarse textured layer, the porous nature of the volcanic gravel and cinders and the deep rooting afforded to crops all contribute to an effective water use. However, the clearing of land in higher areas could lead to an increase of run-off of rainfall at the expense of seepage and lateral movement of the water through the permeable soil. This can eventually disturb the rather delicate water balance in these soils. Soil fertility maintenance: These are light textured soils with less ability to retain nutrients applied as fertilizers than other soils of St. Vincent. The indication from soil analysis is that they inherently have adequate levels of magnesium but the other nutrients should be supplemented with fertilizers. In using fertilizers it must be realized that these soils are not resilient and the balance of nutrients can be easily upset by inadequate use. An example is the available phosphate level for all the soils due to previous fertilizer use. A fertilizer such as 13:13:21 is recommended as a general fertilizer for all crops but this should be reviewed following the response obtained. A rate of 300 - 400 kg/ha per year of the fertilizer should be applied in split applications of not more than two monthly intervals for other crops.

For banana, 600 kg/ha/yr of the fertilizer applied in two-monthly splits should be used.

Soil no. 33

Soil name

Soil classification Chaufleur Clay Shoal soil Loam to Clay Vertic Eutropepts

Rainfall (mm/yr) <1725 Intense dry season

Land area 3014 ac 1218 ha

This is a black to very dark grey brown clay loam on cemented agglomerate and lava with imperfect drainage and moderate permeability; it is stony and bouldery at all depths. It occurs at about 100 m elevation on moderately steep to steep slopes. This is the only soil in St. Vincent with vertic properties i.e. clay texture, firm consistence, sub-angular blocky structure and shrink-swell behaviour. Slope categories and capability classes Slope class Angle of slope (degrees) C-D 2-10 D 10-20 D-E 10-30 E 20-30 F >30

are given below: Land area (ac) (ha) 71 29 439 178 1769 716 358 145 379 153

Capability classes IIe IVb IVe Ve VIe

Current land use and characteristics of site sampled: The site sampled was located near Anse Cayenne and was abandoned from food crop cultivation; the slope was about 15Ë&#x161; and the soil was rocky and bouldery. Most of the area was uncultivated and in scrub vegetation. However, there was much evidence that the soil was used in places for shifting cultivation of hardy food and vegetable crops. Details of the sampling are given below: Soil depth (cm) Sample number 0-15 56 15-30

30-60

Remarks Subsoil extremely hard and compact - almost impossible to auger; soil poorly utilized with shifting cultivation only; very stony and bouldery.

Soil fertility assessment: The analytical results for this soil are given below: Sample depth (cm)

Organic matter %

ENR (kg/ha)

CEC cmol/kg soil

0-15

6.4

2.6

24.0

15-30

6.6

1.8

30-60

6.4

1.8

108 M 90 M 90 M

29.6 14.6

Exchangeable cations cmol/kg soil Ca Mg K 13.95 7.42 0.07 M VH VL 18.45 9.67 0.08 M VH VL 9.60 3.24 0.19 H VH L

Cation aaturation (%) 89 VH 95 VH 89 VH

Avail. P (Bray) ppm P1 2 VL 2 VL 2 VL

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high

Chemical activity: For a soil with over 50 percent sand, the cation exchange capacity values are very high which is in accordance with its vertic behaviour. For this soil the organic matter content is high at all depths and this has also contributed. The soil is likely to firmly fix nutrients added as fertilizers. This soil probably never received any fertilizers in recent times and therefore the levels of plant nutrients is indicative of its inherent fertility only.

Nitrogen: The amount of nitrogen release expected is at a good level for this soil but supplementation would be needed for successful crop production. Phosphorus: The levels of available phosphorus are very low and this is an indication of the inherent levels in the soil since it is likely that no fertilizers were used at the site for some time. Potassium: Levels are very low, again reflecting the inherent soil condition with respect to this nutrient. Magnesium: The levels are very high which is in accordance with the vertic properties of the soil. No supplementation is needed. Calcium: High to medium levels were obtained; no correction is needed for crop production. pH value: Values are ideal for crop production. Land use recommendations: This is an extremely difficult soil on which to grow crops and in addition it is erodible. The intense dry season and lack of opportunities for irrigation are further limitations. Only short term food and vegetable crops coinciding with the wet season can be recommended. It would be interesting to see how mango will 85

P2 3 VL 3 VL 5 VL

perform since the dry season can be an advantage in the maturing and ripening of the crop. Other fruits like soursop, guava for processing, sugar apple and custard apple may be worth trying. Soil fertility maintenance: For all crops, a fertilizer supplying nitrogen, phosphorus and potassium in about the same amounts and no magnesium such as 13:13:21 at about 300 - 400 kg/ha is recommended; there should be split applications during the wet season only.

Soil no. 34

Soil name

Soil classification Ferret Sandy Alluviual soil Loam and Sandy Fluventic Clay Loam Tropudolls

Rainfall (mm/yr) 1725-2125 Marked dry season

Land area 78 ac 31 ha

This is a friable dark brown fine sandy loam on bottom-land alluvium probably derived from the St. Vincent Series (Soil No. 8) on flat relief. It has good drainage and moderate permeability. There are a few stones. It occurs on landscapes below 60 m in elevation and there is only a slight erosion hazard. Slope categories and capability classes Slope class Angle of slope (degrees) A 0-2 B 2-5

are given below: Land area (ac) (ha) 59 24 24 10

Capability classes IIc IIIb

Current land use and characteristics of the site sampled: The site was located near the Government Agricultural Station at Wallilabou; the land was in native pasture in which savanna grass (Axonopus compressus) and timari (Mimosa pudica) predominate; livestock was tied for grazing; there were some nutmeg trees for overhead shade. The whole area was poorly utilized. Details of the sampling are as follows: Soil depth (cm) Sample number 0-15 154 15-30

155

30-60

156

Remarks Area was very wet due to lateral seepage from higher areas; sand content increased with depth

Soil fertility assessment: The analytical results for the soil are given below: Sample depth (cm)

Organic matter %

ENR (kg/ha)

CEC cmol/kg soil

0-15

6.3

2.7

16.8

15-30

6.4

2.2

30-60

6.6

2.0

110 M 99 M 94 M

19.4 18.1

Exchangeable cations cmol/kg soil Ca Mg K 11.05 3.08 0.95 H VH VH 13.20 3.17 0.90 H VH VH 13.5 3.42 0.10 H VH VL

Cation saturation (%) 90 VH 89 VH 94 VH

Avail. P (Bray) ppm P1 33 M 26 M 11 L

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high

Chemical activity: The chemical activity of the soil is high considering that about 55 percent of the soil material is sand. Clearly, the amount and depth of incorporation of the organic matter contributed to this level of activity. Nitrogen: The level of estimated nitrogen release is medium at all depths sampled which indicates that this soil is capable of supplying a substantial part of the nutrient required for crop production from reserves. Phosphorus: The levels of available phosphorus ranged from medium to high up to 30cm depth but below this, the level decreased. These values must come from soil reserves since there was no evidence of crop production and therefore fertilizer application in the recent past. The tethering of livestock at the site could be contributory. Potassium: Very high values for exchangeable potassium were obtained up to 30cm depth, below which the values decreased. The sources for these high levels would be inherent in the soil parent material (alluvium) and from dung and urine of tethered livestock. Magnesium: Very high levels of exchangeable magnesium were obtained which most likely was due to the influence of the soil parent materials and not from previous fertilizer use. Calcium: High values for exchangeable calcium were obtained at all depths; the influence of the parent material is important in this regard. pH value: This is ideal for plant growth and no corrective measures are needed. The high cation saturation obtained is in accordance with the pH values.

P2 58 H 44 H 23 L

Land use recommendations: This is a valuable soil, since, as an alluvial soil, it occurs in an area with very steep slopes and shallow soils. The obvious constraint is the extreme dry seasons but there are good possibilities for irrigation, although this is not in use as yet. Without irrigation, only short term food and vegetable crops can be produced; however, with irrigation, the range of crops can be increased to include banana and plantain. Soil fertility maintenance: This is a fertile soil and only maintenance fertilizer use is recommended. A mixed fertilizer supplying roughly equal amounts of nitrogen, phosphorus and potassium such as 13:13:21 or 20:10:10 at 300 - 400 kg/ha applied in split applications during the active crop growth period is recommended. There should be no additions of magnesium at this stage.

Soil no. 35

Soil name Diamond Loam

Soil Classification Clay Alluvial soil Fluventic Tropudolls

Rainfall (mm/yr) 1725-2125 Marked dry season

Land area 135 ac 54 ha

This is a dark reddish brown clay loam developed on bottom-land alluvium and having good drainage and moderate permeability. It occurs on landscapes lower than 60 m and has slight erosion hazard. Slope categories and capability classes are as follows: Slope class Angle of slope Land area (degrees) (ac) (ha) A 0-2 135 55

Capability class I

Current land use characteristics of site sampled: The site was located near the former Diamond Dairy and the land was used for pasturing of dairy cattle; at time of sampling it was abandoned and there was severe weed growth. Generally, this soil is inadequately used for agriculture at present. Details of the sampling are given below: Soil depth (cm) Sample number 0-15 106 15-30 107 30-60 108

Remarks Soil dry and very compact hence difficult to auger; entire area in native pasture 88

Soil fertility assessment: The analytical results of the soil are given below: Sample depth (cm)

Organic matter %

ENR (kg/ha)

CEC cmol/kg soil

0-15

6.3

2.5

37.3

15-30

6.3

2.4

30-60

6.5

1.3

105 M 103 M 78 L

39.0 36.7

Exchangeable cations cmol/kg soil Ca Mg K 23.4 10.83 0.48 M VH L 26.25 9.50 0.62 M VH M 25.40 9.00 0.54 M VH L

Cation saturation (%) 93 VH 93 VH 95 VH

Avail. P (Bray) ppm P1 6 VL 3 VL 5 VL

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high

Chemical activity: This soil is highly active chemically as indicated by the high cation exchange capacity and amount and depth of penetration of organic matter. Plant nutrients applied as fertilizers would be firmly fixed. Nitrogen: The estimated nitrogen release indicates a good amount of nitrogen being available for crops from soil reserves. Only supplementary fertilizer use is needed. Phosphorus: Available phosphorus is very low at all depths. This soil did not receive fertilizer for a long time and therefore these levels are indicative of soil reserves only. Phosphate fertilization should be emphasized in agricultural use of this soil. Potassium: The values for exchangeable potassium range from low to medium and comes from soil reserves only. For intensive agriculture, supplementation would be needed. Magnesium: Very high values for exchangeable magnesium were obtained throughout and no supplementation is needed. Calcium: Medium levels of exchangeable calcium were obtained throughout which indicates that no corrective measures are needed. pH value : This is ideal for crop growth and no corrective measures are needed. The very high cation saturation is in accordance with the pH values. Land use recommendations: This soil is poorly utilized at present since it occurs in an agro-ecological zone which is too dry for banana, aroids, arrowroot and other traditional crops. Some irrigation is possible but not used at present. This could make an important contribution for agriculture. Due to its strategic location close to populated areas, 89

P2 8 VL 4 VL 7 VL

food and vegetable crops and other crops like water melon and cantaloupe may be quite suitable; some fruits such as sour sop, guava and sugar apple can also be tried. Soil fertility maintenance: A mixed fertilizer supplying roughly equal amounts of nitrogen, phosphorus and potassium but no magnesium such as 13:13:21 and 20:10:10 should be used at about 400 kg/ha applied in split applications during the growing season.

Soil no. 36

Soil name

Soil classification Yambu Sandy Alluvial Soil Clay Loam and Cumulic Tropudolls Clay Loam

Rainfall (mm/yr) 1725-2125 Marked dry season

Land area 50 ac 20 ha

This is a friable very dark brown clay loam on â&#x20AC;&#x153;bottom-landâ&#x20AC;? alluvium on flat relief; the soil has good drainage and moderate permeability; there are few to many stones and boulders and there is only slight erosion hazard in annual cropping. Slope categories and capability classes are as follows: Slope Class Angle of slope Land area (degrees) (ac) (ha) A 0-2 50 20

Capability class IIb

Current land use and characteristics of site sampled: The site was located in the flood plain of the Argyle River which is also the main location for this minor soil. The current land use was native pasture and the whole area was not in intensive use and no arable crops were seen. Details of the sampling are given below: Soil depth (cm) Sample number 0-15 109 15-30 110 30-60 111

Remarks Typical alluvial soil; loam on surface changing to more sandy at depth

Soil fertility assessment: The analytical results of the soil are given below: Sample depth (cm)

Organic matter %

ENR (kg/ha)

CEC cmol/kg soil

0-15

6.3

2.9

21.9

15-30

6.6

1.0

30-60

6.7

1.4

114 M 72 L 81 L

22.4 20.9

Exchangeable cations cmol/kg soil Ca Mg K 13.6 5.42 0.62 M VH VH 14.75 6.00 0.40 M VH M 13.80 5.92 0.32 H VH L

Cation saturation (%) 90 VH 94 VH 96 VH

Avail. P (Bray) ppm P1 2 VL 2 VL 2 VL

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high

Chemical activity: Considering that 40 percent of the soil is sand, its chemical activity as indicated by the cation exchange capacity is high; the soil is therefore expected to firmly fix plant nutrients applied as fertilizer. Nitrogen: The level of estimated nitrogen release is low to medium; it is expected that a good part of the nitrogen needed by a productive crop can be obtained from soil reserves but supplementation would be essential. Phosphorus: The available phosphorus levels are very low at all depths. Fertilizers were not added to the soil for a long time; the very low levels is from soil reserves only. Potassium: Exchangeable potassium is very high in the surface layer but decreased with depth. Here again, the levels are indicative of the native soil reserves and the indication is that in serious crop production, this would need to be supplemented with fertilizers. Magnesium: Very high levels were obtained for exchangeable magnesium which is related to the native soil reserves of this nutrient. Clearly no additions of magnesium is needed for crop production. Calcium: High values for exchangeable calcium were obtained indicating an adequate supply of this nutrient for crop production; no supplementation is needed. pH value: This is ideal for crop growth and no corrective measures are necessary. Land use recommendations: This minor soil is not used at present to its full capability. The stones and boulders are probably a contributory factor but this may not interfere too much for perennial

P2 5 VL 5 VL 7 VL

crops if flash flooding is not a problem. intensive vegetable production.

There is potential for irrigation and

Soil fertility maintenance The natural fertility level of the soil is already high except for phosphorus. Much of the nutrients needed by crops can be supplied from soil reserve and only supplementation may be needed. A fertilizer which emphasizes phosphorus such as 12:24:12 can be used at about 400 kg/ha for vegetable crops which should be applied in split applications during the crop growing period.

Soil no. 37

Soil name

Soil classification Garden Sandy Alluvial Soil Loam and Loamy Fluventic Sand Eutropepts

Rainfall (mm/yr) 2125-2500 Weak dry season

Land area 253 ac 102 ha

This a weak red to yellowish red brown very fine sandy loam on “bottom-land” alluvium derived from Greggs, Montreal and St. Vincent soils. The soil has slightly imperfect drainage and moderate permeability; there are many boulders. It occurs on landscapes below 200 m elevation on gentle to flat relief. Slope categories and capability classes are as follows: Slope class Angle of slope Land area (degrees) (ac) (ha) A-B 0-5 253 143

Capability class IIb

Land use and characteristics of site sampled: The site sampled was located in the Buccament Valley in an area with slope of 4˚5˚; the land around was used for food/vegetable production although the site sampled was recently fallowed and in native pasture; there was a prolific growth of mixed grasses. Details of the sampling are given below: Soil depth (cm) Sample number 0-15 71 15-30 72 30-60 73

Remarks The site was protected and offer good environmental conditions for farming

Soil fertility assessment: The analytical results of the analysis of the soils are given below: Sample depth (cm)

Organic matter %

ENR (kg/ha)

CEC cmol/kg soil

0-15

5.9

2.1

19.0

15-30

6.1

2.0

30-60

6.3

1.3

96 M 94 M 78 L

13.5 13.0

Exchangeable cations cmol/kg soil Ca Mg K 11.65 3.58 0.46 M VH H 8.00 3.17 0.44 M VH H 8.10 2.42 0.24 M VH L

Cation saturation (%) 83 VH 86 VH 83 VH

Avail. P (Bray) ppm P1 16 L 12 L 8 VL

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high

Chemical activity: As indicated by the cation exchange capacity and considering that over 45 percent of the soil is sand, a high degree of chemical activity is shown. Nitrogen: The level of estimated nitrogen release is low to medium and this has to be supplemented with nitrogen fertilizers for good crop yields. Phosphorus: The values for available phosphorus are low on the surface to very low at depth. This was a result of no phosphate fertilization for some time prior to sampling. The levels have to be built up for successful crop production. Potassium: The exchangeable potassium values decreased from high in the top layers of the soil to low at greater depth. There may be some residual effect in this case from previous fertilizer use since the values decreased with depth. Magnesium: Relative to the other exchangeable cations, exchangeable magnesium is very high and for the present, no addition of this nutrient is needed. Calcium: The values for exchangeable calcium show medium levels at all depths. No additions are needed. pH value: This is at a good level for successful crop growth and no corrective measures are needed. Land use recommendations: Clearly this is potentially a fertile and productive soil and can be successfully used for food and vegetable crop production and for banana as well. Supplemental irrigation may be needed. Pastures can be very productive. If the cotton crop is reintroduced, this as well as other alluvial soils can be used.

P2 23 L 17 L 11 VL

Soil fertility maintenance: For the production of most crops, a mixed fertilizer supplying nitrogen, phosphorus and potassium such as 12:24:12 or 13:13:21 can be used at about 400 kg/ha per annum, the fertilizer being applied in split applications during the growing period.

Soil no. 38

Soil name Garden Loam

Soil classification Alluvial soil Fluventic Eutropepts

Rainfall (mm/yr) 2125- 2500 Weak dry season

Land area 39 ac 16 ha

This is a dark brown loam with slightly imperfect drainage and moderate permeability. It occurs on â&#x20AC;&#x153;bottom-landâ&#x20AC;? alluvium on flat relief and in elevations under 200 m. It is derived mainly from Greggs and Montreal soils. The soil is bouldery. Slope categories and capability classes are as follows: Slope class Angle of slope Land area (degrees) (ac) (ha) A-B 0-5 39 16

Capability class IIb

Current land use and characteristics of site and soil sampled: The site was located at Veryvine near Francois in the Upper Buccament Valley. The main crop was aroids but the site sampled was in temporary fallow, an eddo crop having been harvested within the past three months of sampling. Details of the sampling are given below: Soil depth (cm) Sample number 0-15 78 15-30 79 30-60 80

Remarks A relatively flat area in a mountainous region; the soil is stony and bouldery

Soil fertility assessment: The analytical results for this soil are given below: Sample depth (cm)

Organic matter %

ENR (kg/ha)

CEC cmol/kg soil

0-15

5.3

5.7

7.4

15-30

5.2

5.5

30-60

5.5

5.0

188 VH 154 VH 144 VH

2.3 3.0

Exchangeable cations cmol/kg soil Ca Mg K 4.25 0.48 0.40 M L VH 0.95 0.42 0.17 L H VH 1.60 0.38 0.28 M M VH

Cation saturation (%) 69 M 67 M 75 M-H

Avail. P (Bray) ppm P1 4 VL 4 VL 3 VL

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high

Chemical activity: This is low especially at depth and it reflects the influence of the Greggs and Montreal soils which are rich in allophane and from which this soil was derived. Plant nutrients would be weakly held and subject to leaching. Nitrogen: Very high levels of nitrogen can be released from the soil reserves to facilitate crop growth. This is in accordance with the very high organic matter content at all depths. Phosphorus: Available phosphorus is very low at all depths, the reason being that heavy dressings of fertilizers were not used for a period of time prior to sampling. Potassium: Compared to the other cations, exchangeable potassium is rated as very high but in this fine textured allophanic soil, supplementation with fertilizers is needed. Magnesium: The values indicate the need for supplemental dressings of magnesium. Calcium: Deficiencies may not occur at this stage but the situation should be monitored by periodic soil analysis. pH value: Although low, the values are not too low for crop production. Periodic monitoring is needed. Land use recommendation: This is a fragile soil with respect to fertility maintenance. It has excellent physical properties but the fertility levels need to be improved; in this case, it would be suited for crops like banana, plantain and aroids.

P2 5 VL 6 VL 9 VL

Soil fertility maintenance: For banana, plantain and aroids, magnesium containing fertilizers such as 12:12:17:2 and 16:8:24:4 at about 600 kg/ha per annum is recommended. The fertilizer should be applied in about five to six split applications throughout the year.

Soil no. 39

Soil name

Soil classification Greathead Sandy Alluvial soil Clay Loam and Fluvuqentic Clay Loam Tropudolls

Rainfall (mm/yr) 1725-2125 Marked dry season

Land area 203 ac 82 ha

This is a friable dark yellowish brown to very dark brown clay loam on “bottomland” alluvium with imperfect drainage and moderate permeability. The elevation is below 60 m with flat relief. Limitations are flash flooding and occurrence of boulders. The slope categories and capability classes are as follows: Slope class Angle of slope Land area (degrees) (ac) (ha) A 0-2 203 82

Capability classes IIb

Current land use and characteristics of the site sampled: The site was located along the road to Glen about one kilometre from the junction with the Western Highway; the area was in fallow or abandoned and had rank weed growth including vines. There were no signs of recent agriculture. Details of the sampling are given below: Soil depth (cm) Sample number 0-15 100 15-30 101 30-60 102

Remarks Flat land - about 2˚ slope; area stony and bouldery

Soil fertility assessment: The results of chemical analysis of the soil are given below: Sample depth (cm)

Organic matter %

ENR (kg/ha)

CEC cmol/kg soil

0-15

6.0

4.2

30.0

15-30

6.6

1.5

30-60

6.6

1.7

143 VH 83 L 87 M

25.1 27.1

Exchangeable cations cmol/kg soil Ca Mg K 19.35 6.25 0.49 M VH M 19.75 5.58 0.22 H VH VL 19.35 6.17 0.19 H VH VL

Cation saturation (%) 87 VH 100 VH 95 VH

Avail. P (Bray) ppm P1 4 VL 4 VL 3 VL

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high

Chemical activity: The cation exchange capacity values indicate a soil with high chemical activity especially considering that on the average 30 percent of the soil material is sand. The soil is expected to retain plant nutrients applied as fertilizers. Nitrogen: The values for estimated nitrogen release range from very high to medium and therefore it is expected that this soil would supply a substantial part of the nitrogen needs of a crop from reserves. Fertilizers would be needed to supplement this. Phosphorus: The values for available phosphorus are very low which was expected since the site was not used for crop production for some time and therefore was not fertilized. For renewed crop production, phosphate would have to be added. Potassium: Medium to very low values for exchangeable potassium were obtained, reflecting the situation that no fertilizers were applied for some time and there was no residual amount in the soil. Magnesium: Very high values for exchangeable magnesium were obtained and this was inherited from the soil parent material. There is no need to supply additional magnesium for crop production. Calcium: Values for exchangeable calcium ranged from medium to high and no supplementation is needed. pH values: These are ideal for crop production and no corrective measures are necessary.

P2 7 VL 5 VL 5 VL

Land use recommendations: This is a valuable soil which occurs in close proximity to populated areas; intensive market garden production should therefore be profitable. The stones and boulders would be a problem. Perennial crops can also be tried. Prospects for irrigation are not very good and therefore cropping would have to be adjusted to fit the agroecological conditions. Soil fertility maintenance: The fertility of the soil would have to be substantially upgraded for good crop production. Non-magnesic fertilizers supplying nitrogen, phosphorus and potassium which emphasizes phosphorus such as 12:24:12 should be applied at about 400 - 500 kg/ha per annum for market garden crop for instance. The fertilizers should be applied during the growing season. Moisture conservation should be an integral aspect of soil management.

Soil no. 40

Soil name

Soil classification York Sandy Alluvial soil Loam Cumulic and Sandy Clay Haplustolls Loam

Rainfall (mm/yr) 1725-2125 Marked dry season

Land area 386 ac 156 ha

This is a yellowish brown to very dark brown fine sandy loam with good drainage and moderate permeability. It is developed on alluvium in river flood-plains or terraces and the resulting soil has a few stones and boulders. It occurs on flat topography at elevations below 60 m. The top soil can set hard during the dry season and there is some tendency for surface crust development; this is not viewed as serious impediments for agricultural use. Slope categories and capability classes Slope class Angle of slope (degrees) A 0-2 A 0-2 A 0-2

are given below: Land area (ac) (ha) 193 78 170 69 23 9

Capability classes I IIb IIIb

Current land use and characteristics of site sampled: The site sampled was located near Anse Cayenne in a partially developed and developing area. Cultivation was in the nature of home gardens and consisted primarily of mixed food crops such as beans, pigeon pea, sweet potato, plantain and maize. The land was laid out in low ridges. The area was essentially flat (0 2Ë&#x161; slope).

Details of the sampling are as follows: Soil depth (cm) Sample number 0-15 59 15-30 60 30-60 61

Remarks The cultivated patches were small and the emphasis was on mixed food crops

Soil fertility assessment, Land use recommendations and Soil fertility maintenance are presented together with soil no. 41 with which this soil is closely related and is found in the same agro-ecological zone.

Soil no. 41

Soil name

Soil classification York Sandy Alluvial soil Loam and Sandy Clay Loam Cumulic (imperfectly Haplustolls drained variant)

Rainfall (mm/yr) 1725-2125 Marked dry season

Land area 28 ac 11 ha

This is a dark brown sandy loam to sandy clay loam on alluvium with good drainage and moderate permeability. It occurs in river flood-plains and valley floors at elevations less than 30 m in flat relief. The soil has some stones and boulders. Slope categories and capability classes are given as follows: Slope class Angle of slope Land area (degrees) (ac) (ha) A 0-2Ë&#x161; 28 11

Capability classes IIb

Current land use and characteristics of site sampled: The site was located in the lower Buccament Valley in an area with intensive irrigated vegetable production. The sampled area was recently planted with cucumber with only zonal tillage to allow seed planting.

100

Details of the sampling are as follows: Soil depth (cm) Sample number 0-15 68 15-30

30-60

Remarks The entire area was devoted to vegetable production with a high level of management; supplemental irrigation was being used by all farmers

Soil fertility assessment: The two soils York Sandy Loam and Sandy Clay Loam and York Sandy Loam and Sandy Clay Loam (imperfectly drained variant) are closely related in properties and therefore they would be considered together with respect to Soil fertility assessment, Land use recommendations and Soil fertility maintenance. The analytical results for the two soils are given below: Soil No. 40 - York Sandy Loam and Sandy Clay Loam Sample depth (cm)

Organic matter %

ENR (kg/ha)

CEC cmol/kg soil

0-15

6.4

1.5

15.6

15-30

6.5

1.3

30-60

6.7

1.2

82 L 78 L 76 L

19.3 16.0

Exchangeable cations cmol/kg soil Ca Mg K 10.25 3.50 0.13 M VH VL 12.05 5.75 0.14 M VH VL 9.50 5.58 0.21 M VH L

Cation aturation (%) 89 VH 93 VH 96 VH

Avail. P (Bray) ppm P1 2 VL 2 VL 5 VL

P2 5 VL 6 VL 9 VL

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high Soil No. 41 - York Sandy Loam and Sandy Clay Loam (imperfectly drained variant) Sample depth (cm)

Organic matter %

ENR (kg/ha)

CEC cmol/kg soil

0-15

5.9

2.0

16.7

15-30

5.9

1.7

30-60

6.3

1.3

94 M 87 M 78 L

22.0 28.0

Exchangeable cations cmol/kg soil Ca Mg K 9.30 4.08 0.45 M VH H 11.40 6.33 0.55 M VH H 16.6 8.33 0.48 M VH M

Cation saturation (%) 83 VH 83 VH 91 VH

Avail. P (Bray) ppm P1 93 VH 39 M 8 VL

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high 101

P2 123 VH 55 H 15 L

Chemical activity: Considering that about 60 percent of the soil material is sand, the soils have a high degree of chemical activity due to the type of clay minerals present and the amount and depth of incorporation of organic matter. The soils will have good retention of plant nutrients applied as fertilizers. Nitrogen: The levels of estimated nitrogen release ranged from low to medium and therefore the soils would be expected to supply a good part of the nitrogen needed for crop production but supplementation would be necessary. Phosphorus: A wide difference in available phosphorus is shown by the two soils and this is due to difference in soil management. Soil no. 41 was intensively cultivated for vegetable production and the succeeding crops were undoubtedly well fertilized. For this reason, the available phosphorus was high to very high up to 30 cm depth but decreased deeper. Soil no. 40 was farmed for household production of food crops and therefore may have received little or no fertilizers from crop to crop. For this reason, the values for available phosphorus was very low throughout. A higher level of cropping would require systematic applications of phosphate fertilizers. Potassium: Again the influence of management is reflected in the level of exchangeable potassium in soil no. 41 having high values and soil no. 40, very low. Fertilization is needed for increased production. Magnesium: Both soils are very high in exchangeable magnesium which is influenced by the soil parent material; no magnesium fertilization is needed. pH value: These are ideal for crop production and no corrective measures are needed. Land use recommendations: These soils are ideally suited to intensive vegetable and food crops but supplemental irrigation is needed for all-year production. In fact, with irrigation, they are suited for all the crops normally grown in St. Vincent since they have high capability. In managing them, attention should be given not to over-till and simple measures of surface erosion control should be practised such as mulching. Soil fertility maintenance: A non-magnesium containing mixed fertilizer emphasizing nitrogen such as 20:10:10 should be used on vegetable crops. Alternatively, another fertilizer supplying nitrogen, phosphorus and potassium in roughly equal amounts such as 13:13:21 can be used with a side dressing of urea or sulphate of ammonia. Over the year, not more than 500 kg/ha of the mixed fertilizers and 200 kg/ha of the nitrogen fertilizer should be used for intensive vegetable production.

102

Soil no. 42

Soil name

Soil classification Still Sandy Clay Alluvial soil Loam and Clay Loam Cumulic Tropudolls

Rainfall (mm/yr) 1750-2125 Marked season

Land area 267 ac

dry

108 ha

This is a very dark grey to dark grey clay loam on alluvium in â&#x20AC;&#x153;bottom-landâ&#x20AC;?. It has poor drainage and slow permeability but no stones and boulders. It occurs in essentially flat relief in elevations less than 30 m. There is no erosion hazard. Slope categories and capability classes are given below: Slope class Angle of slope Land area (degrees) (ac) (ha) A 0-2 267 108

Capability class IIc

Current land use and characteristics of site sampled: The sample site was located in the Arnos Vale area on a river flood plain; it was a communal, unmanaged, natural pasture. There was a good growth of grasses among which savannah grass ( Axonopus compressus) was prominent. There was no evidence of crop farming in the immediate area. Details of the sampling are as follows: Soil depth (cm) Sample number 0-15 103 15-30 104 30-60 105

Remarks Agricultural use of this land is limited due to low rainfall, intensive dry season and exposure to winds

Soil fertility assessment: Results of analysis of the soil are presented below: Sample depth (cm)

Organic matter %

ENR (kg/ha)

CEC cmol/kg soil

0-15

6.3

2.9

30.0

15-30

6.5

2.6

30-60

6.2

2.4

114 M 108 M 103 M

28.1 38.9

Exchangeable cations cmol/kg soil Ca Mg K 16.1 11.0 0.34 L VH L 16.9 9.17 0.22 M VH VL 23.35 10.0 0.54 M VH L

Cation saturation (%) 91 VH 94 VH 92 VH

Avail. P (Bray) ppm P1 4 VL 4 VL 6 VL

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high

103

P2 12 L 8 VL 8 VL

Chemical activity: This soil has a high level of chemical activity considering the high cation exchange capacity values inspite of the fact that about 40 percent of the soil is sand. The soil is exceptional for the high amount of organic matter and the depth of incorporation which is a contributory factor. Nitrogen: The levels of nitrogen release from reserves is assessed as medium throughout and the expectation is that a good amount of the nitrogen needed by a crop can be supplied from reserves. Phosphorus: Very low values for available phosphorus were obtained which is a clear indication that the soil did not receive any fertilizers for a long time. Potassium: A similar situation existed for potassium where the low values obtained is a reflection of the non-use of fertilizers. Magnesium: Very high values for exchangeable magnesium were recorded which is inherited from the soil parent material. Calcium: Exchangeable calcium levels range from low to medium but no supplementation is needed if the magnesium levels are not increased. pH value: The soil pH is ideal for crop growth - no corrective measures are needed. Land use recommendations: This is a soil with considerable potential for intensive agriculture especially for food and vegetable crop production. The main limitations are the dry season and the possibility of flash flooding occasionally. Water for irrigation is not available at present. Nevertheless, advantage can be taken for crop production during the wet seasons and moisture conservation can also improve the productive capacity. Many short term high value crops can be produced such as water melon, cantaloupe, other cucurbits and passion fruit; protection from winds may be helpful. Soil fertility maintenance: The levels of available nutrients in this soil are low to very low and are indicative of the basic reserves since no fertilizers were used for some time. Adequate fertilization with mixed fertilizers such as 13:13:21 or 20:10:10 can be tried at about 400-500 kg/ha for all crops; the fertilizers should be applied in split applications during the growing season. No ground limestone or magnesium fertilizers are needed.

104

Soil no. 43

Soil name

Soil classification Colonarie Loamy Alluvial soil Sand Cumulic Tropudolls

Rainfall (mm/yr) 1725-2125 Marked dry season

Land area 80 ac 32 ha

This is a dark brown loamy sand on alluvium in a flat â&#x20AC;&#x153;bottom-landâ&#x20AC;? location in the flood-plain of the Colonarie River. Drainage is imperfect and permeability moderate; there are some random boulders. The soil has 55 - 60% sand content. Slope categories and capability classes are given below: Slope class Angle of slope Land area (degrees) (ac) (ha) A 0-2 80 32

Capability class IIb

Current land use and characteristics of site sampled: The site was located on the bank of the Colonarie River close to the junction with the main east coast road; there was a good banana cultivation in its first crop from planting; the crop was irrigated; the rest of the area was in housing or in banana cultivation; some of the soil was temporarily abandoned at the time of sampling. Details of the sampling are as follows: Soil depth (cm) Sample number 0-15 151 15-30

152

30-60

153

Remarks There was some increase in gravel content with depth; only few stones and boulders; good irrigated banana crop

Soil fertility assessment, Land use recommendations and Soil fertility maintenance are presented together with Soil No. 44 (Colonarie loamy sand) with which this soil is closely related; they occur in the same agro-ecological zone.

105

Soil no. 44

Soil name

Soil classification Colonarie Loamy Alluvial soil Sand Typic Tropudolls

Rainfall (mm/yr) 1725-2125 Marked dry season

Land area 117 ac 47 ha

This is a dark brown to dark yellowish brown gravelly loamy sand on â&#x20AC;&#x153;bottom-landâ&#x20AC;? river alluvium with good internal drainage and moderate permeability. It occurs in elevations under 200 m on gently sloping terrain. The soil is stony and bouldery but there is only slight erosion hazard. It has between 55 and 70 percent sand. Slope categories and capability classes are given below: Slope class Angle of slope Land area (degrees) (ac) (ha) A 0-2 117 47

Capability class IIb

Current land use and characteristics of site sampled: The sample site was located just east of the old arrowroot factory on the south bank of the Colonarie River. The site had very good banana cultivation with supplemental irrigation. Details of the sampling are as follows: Soil depth (cm) Sample number 0-15 148 15-30

149

30-60

150

Remarks The whole valley is successfully cultivated with banana made possible with supplemental irrigation; there is an increase in gravel content with depth.

Soil fertility assessment: The two Colonarie soils - soils 43 and 44 are closely related, differing mainly in the texture of the surface layer. For this reason, the Fertility assessment, Land use recommendations and Soil fertility maintenance will be considered together.

106

The results of chemical analysis for the two soil are presented below: Soil No. 43 - Colonarie Loamy Sand Sample depth (cm)

Organic matter %

ENR (kg/ha)

CEC cmol/kg soil

0-15

5.9

3.4

17.7

15-30

6.0

2.5

30-60

6.4

2.2

125 H 105 M 99 M

15.5 17.8

Exchangeable cations cmol/kg soil Ca Mg K 10.35 3.24 1.00 M VH VH 10.00 2.92 0.27 M VH L 11.25 4.33 0.23 M VH L

Cation saturation (%) 82 VH 85 VH 89 VH

Avail. P (Bray) ppm P1 19 L 7 VL 6 VL

P2 33 M 15 L 10 VL

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high Soil No. 44 - Colonarie Gravelly Loamy Sand Sample depth (cm)

Organic matter %

ENR (kg/ha)

CEC cmol/kg soil

0-15

5.9

3.3

14.2

15-30

6.0

3.3

30-60

6.0

2.6

123 H 123 H 108 M

9.7 9.6

Exchangeable cations cmol/kg soil Ca Mg K 9.10 2.00 0.69 M VH VH 6.35 1.43 0.56 H VH VH 5.80 1.53 0.85 M VH VH

Cation saturation (%) 83 VH 86 VH 85 VH

Avail. P (Bray) ppm P1 94 VH 68 VH 55 VH

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high

Chemical activity: The cation exchange capacity of the soils is quite high especially considering that between 55 and 70 percent of the soil material is sand. The high level of organic matter and depth of penetration is an important contributory factor. The soil is expected to have good retention of plant nutrients applied as fertilizers. Nitrogen: The levels of estimated nitrogen release range from medium to high, indicating a good ability of the soil to supply available nitrogen to the growing crop. For optimum crop production, however, supplemental nitrogen would be needed. Phosphorus: Values for available phosphorus for the Colonarie loamy sand is medium in the surface layer but very low deeper in the soil. This is the minimum satisfactory level for crop production and it should not be allowed to get lower. The other soil, the Colonarie gravelly loamy sand had very high values to the

107

P2 177 VH 136 VH 113 VH

extent that they can interfere with the uptake of other plant nutrients such as nitrogen. The levels for this soil would create a nutrient imbalance and could interfere with crop production. Measures should be taken to reduce this through controlled fertilizer use.

Potassium: Again very high values for exchangeable potassium were obtained which is indicative of too much fertilizer being applied. Magnesium: Very high values were obtained which was due both to the over-use of magnesium containing fertilizer and the influence of soil parent material. No magnesium containing fertilizer is needed. Calcium: Values vary from medium to high and no corrective measures are needed. pH values: The pH values obtained are ideal for crop growth and no corrective measures are needed. Land use recommendations: The Colonarie soils have high capability rating and they can be successfully used for the production of any crop which can be grown in St. Vincent. Few boulders randomly distributed might be an impediment to the cultivation of row crops. Wind-breaks may be beneficial to crops like banana and plantain although these crops are successfully grown presently without any particular protection. To maximize the agricultural potential of these soils, some supplemental irrigation would be an asset. Soil fertility maintenance: This is an example in which too much fertilizer was being used. The rate should be reduced and a fertilizer that does not provide additional magnesium should be applied. A fertilizer such as 20:10:10 should be used at about 500-600 kg/ha for banana and the nutrient levels in the soil monitored on an annual basis so that any necessary changes can be made. Land on which banana is not being grown but can be brought into cultivation, a fertilizer such as 13:13:20 at not less than 500 kg/ha should be used and again the levels in the soil monitored for any changes to be made. For crops other than banana and plantain, about 400kg/ha/year of 13:13:20 NPK fertilizer can be used, put on in split applications.

108

Soil no. 45

Soil name Richmond Sand

Soil classification Alluvial soil Typic Troporthents

Rainfall (mm/yr) 1725-2125 Marked dry season

Land area 80 ac 32 ha

This is a very dark grey brown to pale brown gravelly fine sand on river â&#x20AC;&#x153;bottomlandâ&#x20AC;? alluvium. It has good drainage and moderate permeability and occurs at elevations less than 60 m with gently sloping relief. There is a slight erosion hazard; the soil is bouldery. Between 60 and 70 percent of the soil is sand. Slope categories and capability classes are given below: Slope class Angle of slope Land area (degrees) (ac) (ha) B 2-5 80 32

Capability class IIb

Current land use and characteristics of site sampled: The site was located near Richmond on relatively flat land. There was a good banana crop being grown with supplemental irrigation. The entire soil area was in banana cultivation; the crop was well maintained. The details of the sampling are given below: Soil depth (cm) Sample number 0-15 96 15-30

30-60

Remarks At the site there was an unusual spacing for banana in St. Vincent the plants were closer in the row but rows were further apart than the norm

109

Soil fertility assessment: The results of chemical analysis of the soil are given below: Sample depth (cm)

Organic matter %

ENR (kg/ha)

CEC cmol/kg soil

0-15

5.5

3.5

6.1

15-30

5.7

2.4

30-60

5.9

1.9

128 H 103 M 91 M

4.1 6.5

Exchangeable cations cmol/kg soil Ca Mg K 3.35 0.92 0.19 M H L 2.60 0.53 0.15 M M M 4.45 0.83 0.20 H H M

Cation saturation (%) 73 M 65 M 84 H

Avail. P (Bray) ppm P1 23 L 15 L 13 L

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high

Chemical activity: This is low as expected due to the high sand content (55 - 70 percent of the soil). For this soil the organic matter is very important in maintaining some level of chemical activity. The inference is that leaching losses of nutrients added as fertilizers can be considerable if too high dressings are applied; split applications are important. Nitrogen: Due to the high organic matter content and depth of incorporation, the estimated nitrogen release is quite good, ranging from medium to high. Supplemental nitrogen would be needed. Phosphorus: Adequate levels of available phosphorus were obtained, without being superfluous. It would be important to maintain these levels for good crop production. Potassium: The levels of exchangeable potassium obtained were critical in maintaining a good banana crop. It must not be allowed to get any lower. Magnesium: Medium to high values for exchangeable magnesium were obtained; it is important to maintain these levels and for this, a magnesium containing fertilizer is recommended. Calcium: Levels obtained ranged from medium to high, indicating a satisfactory situation; calcium levels should not be allowed to get lower. pH value: These are satisfactory for good crop production but must not be allowed to significantly decrease. Land use recommendations: This is an example of a soil being successfully used for banana production which would not have been possible without irrigation. Without this facility, only annual crops such as peanut, sweet potato and vegetable crops can be produced. This is 110

P2 91 VH 53 M 36 M

a soil with high capability for agriculture but the one limitation is water. Windbreaks may also be helpful especially for banana and plantain. Soil water conservation would be important to make the best use of the available water. Soil fertility maintenance: In the present situation, the farmer is quite successful in maintaining a good level of soil fertility without creating excesses and nutrient imbalances which could be easily done on this somewhat fragile soil. On this soil a magnesium containing fertilizer such as 12:12:17:2 could be used; it is felt that the banana fertilizer 16:8:24:2 is providing too little phosphorus in relation to nitrogen and potassium. A rate of about 600 kg/ha per annum for banana, applied in split applications of 2 monthly intervals can be used and further adjustments can be made based on soil analysis.

Soil no. 46

Soil name

Soil classification Brighton Sandy Beach Sand Clay Loam to Sand Alfic Ustipsamments

Rainfall (mm/yr) 1725-2125 Intensive season

Land area 253 ac 102 ha

dry

This is a very dark grey brown to dark brown loamy fine sand to fine sand formed on beach deposits; it has good drainage and moderate permeability and occurs at elevations of about 60 m on rolling to steep relief. Slope categories and capability classes are as follows: Slope class Angle of slope Land area (degrees) (ac) (ha) B-C 5-10 253 102

Capability class IIIc

Current land use and characteristics of site sampled: The site is in unmanaged natural pasture or scrub vegetation; housing construction is rapidly expanding in the area but home gardens are quite common. Details of the sampling are given below: Soil depth (cm) Sample number 0-15 160 15-30

161

30-60

162

Remarks Upper and middle class housing construction is rapidly spreading in the area; home gardens of food and vegetable crops are important 111

Soil fertility assessment: The analytical results for the soil are given below: Sample depth (cm)

Organic matter %

ENR (kg/ha)

CEC cmol/kg soil

0-15

6.2

2.1

11.8

15-30

6.5

1.3

30-60

6.6

1.8

96 M 78 L 90 M

10.3 9.6

Exchangeable cations cmol/kg soil Ca Mg K 7.00 2.93 0.51 M VH H 6.75 2.25 0.50 M VH VH 6.70 2.0 0.33 H VH H

Cation saturation (%) 88 VH 92 VH 94 VH

Avail. P (Bray) ppm P1 21 L 15 L 17 L

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high

Chemical activity: This soil consists of 75 percent or more of sand and therefore the cation exchange capacities indicate a high level of activity of the clay fraction. The organic matter which it has also contribute to this. The soil, inspite of the texture, has satisfactory capacity to retain plant nutrients applied as fertilizer. Nitrogen: A good level (medium) of nitrogen can be released from reserves by this soil to support crop production and therefore only supplemental nitrogen would be needed as fertilizer. Phosphorus: Considering that the site sampled was not being cropped for a long time prior to sampling, the level of available phosphorus is considered good. For food and vegetable crop, only maintenance levels of fertilizers would be needed. Potassium: Even without any fertilization for a long time prior to sampling, the levels present are very high; only maintenance dressings would be needed. Magnesium: Very high values were obtained which had to come from the soil parent materials; no need for fertilization is indicated. Calcium: Very adequate levels were obtained and no additions are needed. pH: These are ideal for crop growth and no corrective measures are needed. Soil fertility maintenance: The levels of natural fertility in this soil is high and only supplemental fertilization would be needed. A mixed fertilizer such as 13:13:21 at about 400 kg/ha can be used on all crops, applied in split applications. Normal agronomic practices for moisture conservation are highly recommended. This soil should also respond well to organic manures. It is not agro-ecologically suited to banana or plantain and therefore would be used for food and vegetable crops; its other important use is in 112

P2 38 M 38 M 43 H

housing development. For high production of short duration crops, 300 400kg/ha/year of a fertilizer such as 13:13:20 should be used in split applications during the growing season. The soil should benefit from applications of manures and from soil moisture conservation practices such as mulching. Land use recommendations: This soil has climatic limitations caused by severe dry seasons and there are little possibilities for irrigation due to unavailability of water. Further, it occurs in exposed locations. For intensive agriculture, wind-breaks would be an asset. Annual crops such as vegetables, melons and other short duration crops are recommended for cultivation during the wet seasons.

Soil no. 47

Soil name Beach Sand

Soil classification Beach Sand

Rainfall (mm/yr) 1725-2125

Land area

Typic Ustipsamments

Marked dry season

89 ha

222 ac

This soil occurs in narrow strips along the coast particularly in the south; the relief is flat, almost at sea level. Slope categories and capability classes are given as follows: Slope class Angle of slope Land area Capability class (degrees) (ac) (ha) A 0-2 222 90 IIIs Current land use and characteristics of site sampled: The site sampled was located close to the sea at Anse Cayenne; the soil was in residential use but there were home gardens with mixed food and hardy vegetables; the crops included sweet potato, cassava, sorrel, maize, pigeon pea and plantain; this type of use is practised wherever the area is sheltered from sea blast; exposed areas were not being cultivated.

113

Details of the sampling are given below: Soil depth (cm) Sample number 0-15 62 15-30

30-60

Remarks Limitations are coarse soil texture and, probably high salt content, although crops did not show symptoms and droughtiness or salt injury

Soil fertility assessment: The results of chemical analysis of the soil are given below: Sample depth (cm)

Organic matter %

ENR (kg/ha)

CEC cmol/kg soil

0-15

6.3

1.9

15.1

15-30

6.5

1.8

30-60

6.5

1.2

92 M 90 M 76 M

12.1 11.8

Exchangeable cations cmol/kg soil Ca Mg K 9.15 4.12 0.21 M VH L 7.75 3.33 0.14 M VH VL 7.35 3.42 0.12 M VH VL

Cation saturation (%) 89 VH 93 VH 92 VH

Avail. P (Bray) ppm P1 14 L 11 L 21 L

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high The site sampled was at the boundary between soils No. 40 York sandy loam and sandy clay loam and Soil No. 47 Beach sand at Anse Cayenne. While the trend in nutrient levels would be similar for the two soils, the quantities obtained for Beach sand were too high for that soil, especially the cation exchange capacity values. These values must therefore be used as a guide only. In any event, the soil will provide substantial amounts of nitrogen to crops but supplementation would be needed. Potassium was low to very low and magnesium was, if anything, too high in relation to calcium which is the common situation for St. Vincent soils. Phosphorus is naturally low but the soil will respond to fertilization since immobilization of the nutrient would not be significant. Land use recommendations: This soil is preferred for housing developments - mostly for low income people. This trend will continue. However, home gardens for food and vegetable crops are common. Shelter belts would improve the agricultural potential of this soil. Irrigation would be very useful, but there is little possibility of this.

114

P2 24 L 18 L 25 L

Soil fertility maintenance: For food and vegetable crops, a mixed fertilizer supplying nitrogen, phosphorus and potassium in roughly equal amounts i.e. 13:13:21 or 20:10:10 at about 400 kg/ha per annum should be applied in split applications during the growing season. It is assumed that only food and vegetable crops would be produced on this very narrow belt of soil in scattered locations around the southern coast of the island. 7.2

Soils of Bequia

As stated in Section 3.2, the Land use recommendations and Soil fertility maintenance for all of the soils will be presented together due to the similarity of the soils and agro-ecological conditions.

Soil no. 1

Soil name Camel Clay

Soil classification Shoal

Rainfall (mm/yr) <1725 Severe dry season

Land area 827 ac 335 ha

This is a dark red to dark reddish brown friable strong aggregated clay soil on tuff and agglomerate. It has good external and internal drainage but the profile is shallow. Slope categories and capability classes Slope class Angle of slope (degrees) D 10-20 D 10-20

are given below: Land area (ac) (ha) 16 6 811 328

Capability classes IVe VIe

Current land use and characteristics of site sampled: The site was located in a vacant lot in the Richmond area in essentially a residential development; there were several sugar apple and sour sop trees which appeared in good condition. Other natural vegetation consisted of mixed acacia and white cedar up to about 6 m tall; the slope was about 15Ë&#x161;. Details of the sampling are as follows: Soil depth (cm) Sample number 0-15 133 15-30

134

30-60

135

Remarks Slopes fairly steep; soil stony and bouldery; area essentially residential; no irrigation possibilities. 115

Soil fertility assessment: Results of chemical analysis of the soil are given below: Sample depth (cm)

Organic matter %

ENR (kg/ha)

CEC cmol/kg soil

0-15

7.0

3.9

40.9

15-30

6.8

2.9

30-60

6.9

1.8

137 H 114 M 90 M

39.1 32.2

Exchangeable cations cmol/kg soil Ca Mg K 30.95 9.33 0.49 H VH L 29.35 8.75 0.29 H VH VL 30.9 0.92 0.11 VH VL VL

Cation saturation (%)

Avail. P (Bray) ppm P1 8 VL 3 VL 2 VL

99 VH 98 VH 99 VH

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high The organic matter content is high for this soil with deep incorporation and the estimated nitrogen release indicates a good ability to supply nitrogen to a growing crop from soil reserves. The pH values are about neutral and therefore ideal for crop growth. The soil is highly chemically active with high cation exchange capacities at all depths. Phosphorus and potassium would have to be supplemented for good crop production but calcium and magnesium occur in excess and no additions are needed. The main constraints to agriculture on this soil are shortage of water, shallow soil depth, and occurrence of stones and boulders.

Soil no. 2

Soil name Mount Clay

Soil Rainfall classification (mm/yr) Pleasant Low Level Yellow <1725 Earth

Land area 81 ac 33 ha

This is a dark reddish brown very friable clay soil with evidence of earthworm activity; it is developed on tuff and agglomerate on fairly gentle slopes; it has a deeper profile and higher clay content than Camel Clay which is closely related. Slope categories and capability classes Slope class Angle of slope (degrees) A-B 0-5 C 5-10

are given below: Land area (ac) (ha) 40 16 41 17

Capability classes IIs IIIs

116

P2 17 VL 8 VL 4 VL

Current land use and characteristics of site sampled: The site was located near Mt. Pleasant on about 10Ë&#x161; slope; it was abandoned and had tall grass vegetation; there was some livestock farming being done but the pasture was native and unimproved; in the past the soil was used for cotton and/or sugar cane production and was recognized as being one of the most suitable soils in Bequia for these crops. The main constraints to agriculture are doughtiness and compact soil. Details of the sampling are as given below: Soil depth (cm) Sample number 0-15 130 15-30 131 30-60 132

Remarks The entire soil was once cultivated since it is all in grasses at present.

Soil fertility assessment: Results of the chemical analysis of the soil are given below: Sample depth (cm)

Organic matter %

ENR (kg/ha)

CEC cmol/kg soil

0-15

7.5

4.8

39.5

15-30

7.0

3.9

30-60

7.0

2.7

157 VH 137 H 110 M

56.9 56.0

Exchangeable cations cmol/kg soil Ca Mg K 25.3 14.1 0.14 M VH VL 37.2 19.4 0.23 H VH VL 37.5 18.2 0.06 H VH VL

Cation saturation (%) 100 VH 99 VH 99 VH

Avail. P (Bray) ppm P1 2 VL 2 VL 2 VL

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high The organic matter content is high with deep incorporation and the estimated nitrogen release indicates a good ability of the soil to provide nitrogen to a growing crop. The soil is highly chemically active with high cation exchange capacity values. Without previous fertilization, the levels of phosphorus and potassium are low. The overall indication is that nitrogen, phosphorus and potassium would have to be provided in fertilizers for good crop production. The pH values are ideal for crop growth. Calcium and magnesium are present in large quantities and no supplementation is needed.

117

P2 3 VL 3 VL 4 VL

Soil no.

Soil name

Union Level Clay

Soil Rainfall classification (mm/yr) Low Level Yellow <1725 Earth/ Shoal soil

Land area 786 ac 318 ha

This is a dark brown to yellowish brown clay to silty clay loam with firm, medium to large columnar structure, it has developed on tuff and agglomerate. It has good external drainage and moderate permeability. Slope categories and capability classes Slope class Angle of slope (degrees) D 10-20 E 20-30

are given below: Land area (ac) (ha) 286 116 500 203

Capability classes Ve VIe

Current land use and characteristics of site sampled: The site was located between Industry and Park Estate on steeply sloping land; the area was in scrub vegetation, consisting of white cedar, Cordia spp. and Acacia spp. to about 4 m high, there was no sign of recent cropping. Details of the sampling are as follows: Soil depth (cm) Sample number 0-15 127 15-30 128 30-60 129

Remarks Soil very stony bouldery

and

Soil fertility assessment: Results of chemical analysis of the soil are given below: Sample depth (cm)

Organic matter %

0-15

7.7

4.6

15-30

7.8

3.8

30-60

7.9

2.4

ENR (kg/ha)

152 VH 123 H 103 M

CEC cmol/kg soil 45.0 50.0 25.7

Exchangeable cations cmol/kg soil Ca Mg K 24.8 19.6 0.59 L VH M 26.1 23.2 0.58 L VH L 2.75 22.5 0.45 VL VH M

Cation saturation (%) 100 VH 98 VH 100 VH

Avail. P (Bray) ppm P1 3 VL 2 VL 2 VL

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high This is a soil with high cation exchange capacity and high organic matter content with deep penetration so it is expected that it will immobilize nutrients added as fertilizers. Available phosphorus and exchangeable potassium are low and without

118

P2 7 VL 5 VL 4 VL

any history of fertilizer use, indicate the native levels of these nutrients in the soil. Magnesium and calcium are in abundant supply and no amendments are needed. The pH values are too high for good crop production. However, the soil has naturally very low suitability as an agricultural soil due to its instability and difficult physical condition; it is also stony and boulder. There are no obvious possibilities for irrigation.

Soil no. 4

Soil name Cinnamon Garden Clay

Soil classification Shoal soil

Rainfall (mm/yr) <1725

Land area 265 ac 107 ha

This is a black to dark brown soil with sub-angular blocky structure which is plastic and cohesive. It was formed on cemented tuff; the subsoil showed typical vertic properties. There is restricted internal drainage and permeability. The soil is stony and rocky. Slope categories and capability classes Slope class Angle of slope (degrees) C 5-10 C 5-10 D 10-20

are given below: Land area (ac) (ha) 67 27 40 16 158 64

Capability classes IIIe IIIs IVe

Current land use and characteristics of site sampled: The site was located near Cinnamon Garden where the vegetation was acacia scrub; there were no evidences of recent farming activity in the area. Details of the sampling are as follows: Soil depth (cm) Sample number 0-15 118 15-30

119

30-60

120

Remarks Soil not in agriculture but in native acacia scrub; at one other location, there was some evidence of native pasture but no livestock was seen

119

Soil fertility assessment: The results of the chemical analysis of the soil are given below: Sample depth (cm)

Organic matter %

ENR (kg/ha)

CEC cmol/kg soil

0-15

6.5

3.4

35.2

15-30

6.7

3.2

30-60

6.8

2.8

125 H 121 H 112 M

33.7 56.2

Exchangeable cations cmol/kg soil Ca Mg K 18.2 15.0 0.25 L VH VL 17.2 15.3 0.16 L VH VL 30.3 25.0 0.21 L VH VL

Cation saturation (%)

Avail. P (Bray) ppm

95 VH 97 VH 100 VH

P1 4 VL 2 VL 7 VL

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high Like the Union Level soil, this soil has a high cation exchange capacity at all depths and high organic matter contents with deep incorporation. It is expected to firmly hold nutrients applied as fertilizer. Available phosphorus and exchangeable potassium are low and without any history of recent fertilizer use, these levels are in equilibrium with the native soil reserves. Magnesium and calcium are in abundant supply and no amendments are needed.

Soil no. 6

Soil name Friendship Clay

Soil classification Alluvial soil

Rainfall (mm/yr) <1725

Land area 320 ac 130 ha

This is a friable dark reddish brown clay on alluvium; at depth, there are weak vertic features; the only occurrence is around Friendship Bay. This is the best soil on Bequia for crop production due to its flat relief, deep profile, lack of stones and boulders and relatively favourable physical and chemical properties. Slope categories and capability classes Slope class Angle of slope (degrees) A 0-2 B 2-5 B 2-5

are given below: Land area (ac) (ha) 225 91 50 20 45 18

Capability classes IIc IIIe IIIs

120

P2 8 VL 9 VL 14 L

Current land use and characteristics of site sampled: The site was located in the Friendship Bay area on flat land cultivated with food crops - pigeon pea, cassava, sweet potato and ochro. Most of the soil was in this usage; cropping alternated with fallow. Details of the sampling are as follows: Soil depth (cm) Sample number 0-15 139 15-30 140 30-60 141

Remarks There was an increase in compaction with depth

Soil fertility assessment: Results of the chemical analysis of the soil are given below: Sample depth (cm)

Organic matter %

ENR (kg/ha)

CEC cmol/kg soil

0-15

6.9

4.1

32.7

15-30

6.9

3.0

30-60

7.0

2.3

141 VH 116 M 100 M

33.5 37.2

Exchangeable cations cmol/kg soil Ca Mg K 24.6 6.75 1.0 H VH VH 25.6 7.08 0.47 H VH L 28.4 8.25 0.43 H VH L

Cation saturation (%) 99 VH 99 VH 100 VH

Avail. P (Bray) ppm P1 12 L 17 L 19 L

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high The organic matter content is high and there is deep incorporation; the clay fraction also contains minerals of high cation exchange capacity; consequently the soil is quite active chemically. Nutrients applied as fertilizers would be held in the soil. The estimated nitrogen release indicates a good amount of native soil nitrogen being available to a growing crop but supplementation would be needed. Available phosphorus levels are fair, The results and field observations indicate that there are small shell fragments in the soil which became solubilized in the extraction process and this was estimated as available; this is therefore an overestimate. Exchangeable potassium is high on the surface but decreased with depth; this was due to fertilizer use. Calcium and magnesium levels are high to very high and no correction would be needed. Further, the pH values are ideal for crop growth. This soil is rated as potentially fertile and productive.

121

P2 66 VH 84 VH 280 VH

Soil no.

Soil name

Paget Farm Clay

Soil classification Alluvial-colluvial soil

Rainfall (mm/yr) <1725

Land area 150 ac 61 ha

This is a dark brown clay formed on eroded materials from more elevated terrace areas; the soil is stony and bouldery and at depth rounded stones of augiteandesite and basalt can be very prominent. At depth up to 25 percent of the material can be powdery calcium carbonate accretions. Around the stones there were also manganese oxide encrustations; the soil is unstable as there were evidence of slumping. Slope categories and capability classes are as follows: Slope class Angle of slope Land area (degrees) (ac) (ha) B-C 8-20 150 61

Capability class IVs

Current land use and characteristics of site sampled: The area is partly in housing and partly abandoned; there were few attempts at home garden production. The construction of the airport in the vicinity seemed to have encouraged housing developments. With a severe dry season, no possibilities for irrigation, and exposure to winds, agriculture in the area would be constrained accordingly. The site was located at the rear of the Police Station on sloping land with boulders; the vegetation consisted of Antigua hay grass and some euphorbs. Details of the sampling are given below: Soil depth (cm) Sample number 0-15 136 15-30 137 30-60 138

Remarks Many stones but tree crops can probably be successfully grown

122

Soil fertility assessment: The results of the chemical analysis of the soil are given below: Sample depth (cm)

Organic matter %

ENR (kg/ha)

CEC cmol/kg soil

0-15

7.9

1.8

53.1

15-30

7.3

2.8

30-60

7.2

2.3

90 M 112 M 101 M

44.6 45.9

Exchangeable cations cmol/kg soil Ca Mg K 37.8 14.75 0.51 H VH L 35.2 9.25 0.17 VH VH VL 36.8 9.17 0.13 VH VH VL

Cation saturation (%)

Avail. P (Bray) ppm P1 5 VL 2 VL 2 VL

100 VH 100 VH 100 VH

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high The soil is highly active chemically due largely to the type of clay minerals present and not so much to the organic matter content, which, although good for tropical soils, is lower than the average for Bequia soils. Some nitrogen release from soil reserves to a growing crop can be expected but this would be limited due to the great stability of the organic fraction. Available phosphorus and exchangeable potassium are low since the site probably never received any fertilizers in the past. Calcium and magnesium are very high and no correction is needed. The pH values of the soil are above seven which is due to a small amount of free lime in the soil.

Soil no. 8

Soil name Spring Clay

Soil classification Alluvial soil

Rainfall (mm/yr) <1725

Land area 37 ac 15 ha

This is a dark reddish brown clay on coastal alluvium occurring typically at Spring Estate. The soil had shell fragments throughout and there was evidence of crab activity; the drainage was impeded. Slope categories and capability classes are as follows: Slope class Angle of slope Land area (degrees) (ac) (ha) A-B 0-2 37 15

Capability class IIIs

Current land use and characteristics of site sampled: The site was located at Spring Estate on flat land with old coconut trees which have long past their most productive stage. The ground vegetation was native pasture and there were a few livestock.

123

P2 12 L 9 VL 15 VL

Details of the sampling are as follows: Soil depth (cm) Sample number 0-15 121 15-30

122

30-60

123

Remarks Although the site was close to the sea, there were no evidences of sodic influences in the soil, although there were shell fragments

Soil fertility assessment: Results of chemical analysis of the soil are given below: Sample depth (cm)

Organic matter %

ENR (kg/ha)

CEC cmol/kg soil

0-15

7.6

4.4

33.6

15-30

7.6

3.3

30-60

7.6

3.2

148 VH 123 H 121 H

43.9 40.4

Exchangeable cations cmol/kg soil Ca Mg K 27.4 5.58 0.56 VH VH M 33.7 9.91 0.25 VH VH VL 30.5 9.67 0.24 H VH VL

Cation saturation (%) 100 VH 100 VH 100 VH

Avail. P (Bray) ppm P1 19 L 10 L 4 VL

ENR = estimated nitrogen release; CEC = cation exchange capacity; VL = very low; L = low; M = medium; H = high; VH = very high This is a clay soil with cation exchange values being characteristic of montmorllonite clay minerals; the soil therefore has a high degree of chemical activity and would be expected to retain nutrients applied as fertilizers. Available phosphorus levels indicate the influence of shell fragments as in the case of Friendship clay - the values are therefore over-estimated. Potassium levels are medium and the closeness of the sea may have had some influence on this value. Calcium and magnesium are both very high and no correction is needed. The pH values are over seven due to the influence of the inter-mixed shell fragments. Due to several features such as flat relief, soil depth, fertility status and lack of stones and boulders, this soil has considerable potential for intensive agricultural use and has greater potential than for the predominant coconut and native pasture for which it is now used. The main constraint as for the whole of Bequia is doughtiness, unreliable rainfall distribution and little or no possibilities for irrigation. Land use recommendations and Soil fertility maintenance: In considering crop suitability for Bequia, the important related factors are a rainfall distribution which would allow a growing season of six months maximum and that the unavailability of irrigation would not extend the growing season. 124

P2 86 VH 24 L 16 L

Other factors are steep slopes and shallow, stony soils which cannot withstand any accelerated erosion. The climate and the soils are unsuited to banana cultivation and there does not seem much scope for sugarcane and cotton for which the environment may be considered suitable and which were previously produced. The alternatives seem to be food crop production at least to meet local needs in the first instance. Among the food crops which may be considered suitable are root crops such as sweet potato, yam, cassava, the aroids and grain legumes. Some banana and plantain may be attempted in sheltered locations but only to meet local demand. Pineapple may be a crop which can be easily adapted to Bequia. The pattern of rainfall could ensure good fruit quality and the soils have general suitability for this crop. If well cultivated the soil would need to be tilled only when the crop is replanted and not every year. Many vegetable crops can be successfully grown including tomato, beans, sweet pepper, egg plant, cabbage, cauliflower, okra, pumpkin, squashes, cucumber, onion and melons. Some of these have export potential, if not only to St. Vincent, but to the rest of the Caribbean along with the existing trade in food crops. Improved livestock production would appear to be a good possibility but the problem would be to find naturally adapted grasses and legumes. On cleared land some grass has naturally colonized but no dominant potential forage legumes were seen. However, a few species may be adapted particularly Leucaena and in some sheltered areas, even Gliricidia. Some of the lands can be made more productive if adapted fast growing forest species could be found. Among the possibilities are Eucalyptus spp., Gmelina, teak, mahogany and giant Leucaena. Leucaena may be a very useful species since it can be used to make good charcoal which is in demand in the State. Teak, mahagony and Eucalyptus species have the potential of providing useful timber. Other benefits from planted forests would be improved soil and water conservation and an improvement in the aesthetic quality of the environment in an island in which tourism has so much potential. The environmental conditions of Bequia seem suited to some tropical fruits which are adjusted to a marked dry season in their annual cycle; examples of such fruits are mango, sapodilla, sour sop, sugar apple, custard apple, golden apple, mammie apple, guava and genip. It would be very useful for some of these to be tested for adaptability. Fresh fruit for the local and Caribbean markets and value added products for the international markets could be the outlets for such production.

125

A tentative soil suitability for the various uses is as follows: Crops Class I Class II Class III Food crops Friendship Spring Cinnamon Garden And vegetables Mt. Pleasant Paget Farm Camel Pineapple Mt. Pleasant Camel Cinnamon Garden Pasture Mt. Pleasant Camel Cinnamon Garden Forest and Tropical fruits

All soils with slopes 15Ë&#x161; - 30Ë&#x161;

The maintenance of fertility of the soils must recognize that with the exception of Friendship clay none of the soils would have received any appreciable fertilizers in the recent past and therefore the three major nutrients nitrogen, phosphorus and potassium would need to be applied. Levels of calcium and magnesium are certainly very adequate and it is very unlikely that any of the essential minor elements would be deficient in the small island territory due to marine influences. Experience in fertilizer use would have to be gained over time but as a beginning a mixed fertilizer with analysis of 20:10:10 which emphasizes nitrogen could be initially tried. Another fertilizer such as 13:13:21 could also be tried possibly with supplemental nitrogen in the form of urea or sulphate of ammonia. A rate of 400500 kg/ha applied in splits during the growing season should yield satisfactory results. This should be associated with soil water conservation techniques and appropriate anti-erosion measures such as use of grass strips, run-off drains, individual terraces and soil surface protection. Organic manures may prove very beneficial. It is not recommended that large scale bench terracing using the bulldozer for construction should not be attempted.

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7.0

CONCLUSIONS

The main conclusions which can be made from this study are as follows: 1. The agricultural soils of St. Vincent are generally in good condition, even after many years of intensive agriculture. The soil resources of the island can be considered as very substantial. The high fertility levels are due to good farming practices and periodic rejuvenation from volcanic ash falls resulting from eruptions. 2. The farmers are quite skilful in managing the soils and many practices have an inherent component of soil conservation. There is a strong tradition of fertilizer use for increased productivity. 3. Farmers are aware of the dangers of accelerated erosion and seek help in extreme cases. 4. The fertility levels of the soils have a close relationship to recent agricultural use and particularly the commercial production of banana and food crops. In these uses high fertilizer rates were adopted to enhance crop production and the current fertility levels of the soils are high due mostly to the residual effects of the fertilizers. 5. Once active cropping has ceased or suspended, the fertility levels in the soils decrease rapidly. It is not known how rapidly this can be built up again by renewed cropping and use of fertilizers. 6. The high levels of residual fertility indicate that although soil erosion is occurring, the rate is not rapid, otherwise the topsoil with higher fertility levels would have been lost. 7. In many of the soils the residual fertility is incorporated at depth in the profile which indicates that some movement in the soil of added fertilizers is occurring; this is facilitated by the high permeability of the soils and the commonly high rainfall regimes. 8. Fertilizers were used indiscriminately in the past and without any attention being given to the fertility levels in the soils. Consequently, for many of the soils there is almost an imbalance of plant nutrients particularly for the cations. This could interfere with their proper uptake and metabolism. Similarly, in some instances, the available phosphorus is too high and can interfere with the uptake and metabolism of nitrogen. 9. There is clear indication that additions of magnesium on St. Vincent soils are not needed on an annual basis. For some of the soils the ratio of calcium to magnesium is already too low, which can interfere with calcium uptake. The limited soil analysis reported by Ahmad (1981) showed the same relationship. 10. For most of the soils the parent materials provide a good supply of potassium and only supplementation is needed. 11. The need for the use of ground limestone is not indicated. Only for the minor largely non-agricultural soil (Montreal Loam and Clay Loam alluvial - colluvial variant) was the soil pH below 5. In the majority of

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12. 13.

14.

15.

16.

cases the soil pH was between 6 - 7, indicating ideal soil conditions for crop growth. The cation saturation of all the soils is high and this is a very satisfactory state. Future soil fertility maintenance should be more dynamic and based on periodic soil analysis; fertilizers with different ratios of nutrients should be rotated so as not to create an imbalance of nutrients and superfluous rates should be avoided. The soils of Bequia are unleached and have high pH values, around neutrality; they all show some properties of Vertisols which is expected due to the low rainfall and pattern of distribution and base rich soil parent materials. The soils of Bequia except one - Friendshop clay are not actively being farmed although there are indications that this was done before. Their fertility status is low compared to the St. Vincent soils due to a history of fertilizer use. Only Friendship clay which is in fairly intensive use for food and vegetable crop production has a fertility status which is influenced by current fertilizer use. Any agricultural development in Bequia should emphasize tree crops, pasture and short term food and vegetable crops. This is because there is a long and intensive dry season and no possibility for irrigation except through water storage.

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9.0

LITERATURE CITED

Ahmad, N. 1987. Land capability of St. Vincent and the Grenadines (Bequia). The Organization of Americal States, Kingstown, St. Vincent. Ahmad, N. 1981. An investigation of soil conditions in farmersâ&#x20AC;&#x2122; holdings in St. Vincent. Caribbean Agricultural Research and Development Institute, The University of the West Indies, St. Augustine, Trinidad, W.I. Beard, J.S. 1949. Natural vegetation of the Windward and Leeward Islands. Oxford Forestry Memoir No. 21, Oxford University. Council on Soil Testing and Plant Analysis. 1980. Methods for Soil Testing (Revised Edition). IIII Plant Science Building, University of Georgia, Athens, Georgia, USA 30602. Klingebiel, A.A. and Montgomery, P.H. 1966. Land capability classification. USDA Soil Conservation Service. US Government Printing Office, Washington D.C., USA. Macfarlane, M. and Walmsley, D. 1977. Effect of soil solution phosphorus in volcanic ash soils on the response of tomato (Lycopersicum esculentum) to added pgosphate. Plant and soil 47: 547-558. Marshall, R.C. 1932. Report on Forestry in Grenada. Govt. Printing Office, Grenada. Watson, J.P., Spector, J and Jones, T.A. 1958. Soil and Land Use Surveys No. 3. St. Vincent.

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