Baseline Study Soil - St. Vincent. N. Ahmad

BASELINE STUDY ON THE SOILS OF ST. VINCENT AND THE GRENADINES WITH EMPHASIS ON MAINTENANCE OF PRODUCTIVITY

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

N. Ahmad Department of Food Production Professor Emeritus of Soil Science The University of the West Indies

CONTENTS Page Nos. 1.

Rationale, terms of reference and presentation of reports

1

2.

Soils investigations carried out in St. Vincent prior to 2003

2

3.

Literature

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2

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 1950’s in support of the soil survey of Watson et al. (1958). (ii) The analytical methods and procedure 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 effect but also to continued soil loss throughout 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 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 prior to 2003

The literature would be listed and reviewed in chronological order as required by the terms of reference.

2

Sands, W.N. 1912. An account of the return of vegetation and the revival of agriculture in the area devastated by the Soufrière of St. Vincent in 1902 - 3.

West Indian Bulletin 12:22 - 33. (See Attachment 1) This is a well written highly informative publication on the effects of the 1902 - 3 volcanic eruptions in St. Vincent on the vegetation of the parts of the island that were affected and the resulting dislocations to agriculture. The trends in the reestablishment of the vegetation and attempts to utilize some of the lands for agriculture over an eight-year period following the eruptions were described.

After eight years following the eruption, the vegetation on the mountain slopes and other places had largely been re-established and agricultural conditions were almost back to normal, moreso on the windward side of the island compared to the leeward, on account of the difference in topography and difficulties of access on the steeper leeward side.

Sands W.N. 1915. Method of working small holding under the land settlement scheme, St. Vincent. West Indian Bulletin 14: 24 - 35. (See Attachment 2) Farming systems on small holdings under the land settlement scheme were described. The importance of food crop production such as tannia, sweet potato, cassava, pigeon pea and yam or banana and plantain and the interfacing of the commercial crops of cotton and arrowroot with pasture production were described and discussed. The skill of the farmers in selecting crops for particular sites was emphasized as was the sensitivity to soil erosion. The farmers were aware of, and appreciated the need for, simple soil conservation measures since then. The importance of exports of food crops to Trinidad, Grenada and the Grenadines to stimulate production was emphasized, which is important up to the present.

Indigenous methods of soil fertility maintenance particularly crop rotations and selecting the most suitable crops for particular sites (a land capability factor) are emphasized in the article.

This article is of historical importance. There has been important changes to the farming systems described compared to those practised presently.

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Harland, S.C. 1917. Manurial experiments with arrowroot in St. Vincent. West Indian Bulletin 16: 256 - 259. (See Attachment 3) Two sets of experiments were conducted to assess the response of arrowroot (then viewed as the chief staple crop in St. Vincent) to manures and fertilizers.

The first experiments were conducted with the following objectives: (i) to test the value of mulching with prunings of Madre del Cacao (Gliricidia maculata) (ii) to compare the relative values of various combinations of organic manures and fertilizers.

While there were yield increases from fertilizer applications, the largest increase was to mulching.

In the second experiment, nine different combinations of fertilizers and manures were applied. The materials used included sulphate of ammonia, basic slag, sulphate of potash, cotton seed meal and mulch with glyricidia prunings.

With the exception of the nitrogen alone plot, all the other treatments yielded significantly better than the control. Once again, mulching was superior.

Harland, S.C. 1917. Manurial experimens with sea island cotton in St. Vincent with some notes on factors affecting the yield. West Indian Bulletin 16: 169259. (See Attachment 4) Fertilizer and manurial experiments were carried out with sea island cotton for the years 1912 - 1918. The following treatments were tested: • no manure and no fertilizer • nitrogen alone • phosphorus alone • potassium alone • phosphorus and potassium • nitrogen, phosphorus and potassium • cotton seed meal • cotton seed meal, phosphorus and potassium It was found that differences in manurial treatment did not cause any notable differences in the percentage of flowers producing ripe bolls. Also, there were great differences in yield from year to year due to the variations in weather rather than to responses of fertilizers and manures.

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In general, all the treated plots showed increases in yield, the increase in the case of the plot which received manure plus complete fertilizers amounting to 116 percent.

The nutrient most necessary was potassium, an application of potash producing an increase of up to 75 percent. This nutrient influences the formation of starches and sugars in the plant and appears to be indispensable for protein formation. A lack of it may lead to the appearance of “rust” a physiological disease resulting from deficiency of the element. The reddish coloured leaves which were produced tended to be shed prematurely. There was no evidence that the “rust” led to any diminution in the number of bolls which opened when once formed.

Phosphate and potash applied together was less beneficial than potash alone; also fertilizers plus cotton-seed meal were better than either cotton seed meal or fertilizer alone.

Manures had no effect on the time of maturing of the crop and on the percentage of bolls to flowers. The yield obtained when two plants per hole were left was significantly greater than when there was only one; spacing had no effect on the percentage of bolls to flowers.

These experiments were well planned and conducted and the results and conclusions were well made. At the time this work was carried out, it was most likely some of the most advanced anywhere in the world on cotton. If the cotton crop were to be re-introduced into St. Vincent, it would be necessary to take cognizance of Harland’s findings in managing the soil and crop.

Harland, S. C. 1918. Manurial experiments with sea island cotton (1917-1918 experiments). West Indian Bulletin. 17: 69 – 82. (See Attachment 5) The results and conclusions made in attachment 4 were largely confirmed in the experiments which continued in 1917-18.

Hardy, F., Robinson, C.K. and Rogriguez, G. 1934. Studies in West Indian Soils VIII. The Agricultural Soils of St. Vincent. The Imperial College of Tropical Agriculture, St. Augustine, Trinidad, W.I. 44p. (See Attachment 6) This is the first serious study of the agricultural soils of St. Vincent. The authors studied 42 soil profiles and took 319 soil samples for analysis from fields cultivated with arrowroot, cotton, sugar cane and coconut. In addition, special composite plot samples were taken for the purpose of characterizing the soil of sites selected for proposed fertilizer experiments or sites where soil conditions were apparently peculiar in relation to the growth and development of the 5

arrowroot crop, especially the development of abnormally thin cigar-like rhizomes. The following summarises the publication: (1)

(2)

(3) (4)

(5) (6)

(7)

A brief description of the topography, climate, agriculture, geology, petrography, mineralogy and soil formation in St. Vincent is first given, and frequent comparisons are drawn with the conditions obtaining in the neighbouring island, Grenada.

The chief soil-forming rocks occurring in St. Vincent are loose volcanic agglomerates, including boulders, stones, sand and ash; compact lavas are less plentiful. The petrological types are andesites and basalts, containing hypersthene, augite, olivine and soda-lime feldspars. The rocks of Grenada consist mainly of basalts and andesite lavas, fragmental rocks being less plentiful. Hypersthene is not so abundant, but hornblende is conspicuous. The rocks of St. Vincent contain significantly less potash than those of Grenada.

Details of the methods employed in the soil investigations, involving soil profile studies and laboratory analyses of representative rock and soil samples, are presented.

The soil-types of St. Vincent differ according to the nature of the parent rocks that have given rise to them. The chief soil-types are: (I) Yellow Earth Soils, derived from andesitic and basaltic agglomerate, ash and lava; (II) Alluvial Soils, occurring in Coastal Plains and Valley Deltas, and (III) Recent Volcanic Ash Soils, derived from fragmental ejecta erupted by Soufrière in 1902 - 3.

Generalised descriptions are given of each of the soil-types, based on field observations and laboratory data contained in an Appendix.

The soils of St. Vincent are characterized by the following features: a. immaturity, as indicated by (i) high contents of unaltered minerals grains; (ii) marked vertical uniformity (except where old buried soils occur); (iii) grey, pale-brown or yellow colours; (iv) low contents of colloidal weathering products; b. high permeability to water, due to their sandy nature; c. medium-high contents of organic mater, which penetrates deeply; d. neutral to slightly acidic reaction; e. low rate of solution of the mineral components; f. variable though relatively low contents of available phosphate and potash; g. low saturation capacity and low contents of exchangeable bases, but a high degree of saturation by bases.

The results of manurial experiments conducted in St. Vincent with the main crops (cotton, arrowroot, sugarcane and maize), are discussed in their bearing on the question of the nutrient requirements of the agricultural lands of the island.

6

(8)

(9)

The soil and plant relationship responsible for the incidence of abnormal “cigar� arrowroot rhizomes are considered, and the conclusion is drawn that an unsatisfactory nitrogen and potash status of the soil is the main cause of the abnormality.

The role of organic matter in the fertility of the soils of St. Vincent is critically discussed, and the conclusion is reached that its chief virtue lies in its content of nutrient elements that are liberated during decay, although its solubilising effect of soil minerals, due to the formation of carbonic oxide by oxidation, may also be important.

A simple classification of the soils of the island was proposed i.e. high level yellow earth, low level yellow earth, shoal, alluvial soil and beach sand. This classification is still being used.

While some of the conclusions made about the soils are valid up to the present, much of it is out-dated. The analytical methods employed are no longer in use and the data cannot be interpreted today. However, the study formed an extremely useful and appropriate back-ground for the systematic soil survey which was later conducted by Watson et al. (1958) and other subsequent soils studies. It still remains an important reference for the occurrence an properties of the soils of St. Vincent.

Hamilton, R.A. 1934. The application of mineralogical methods in the study of tropical soils. AICTA Thesis. The Imperial College of Tropical Agriculture, St. Augustine, Trinidad, West Indies. 20p (See Attachment 6a).

In this study which is very preliminary in nature, the mineralogical microscope was used to identify the primary minerals in the soils derived from volcanic materials from St. Vincent and Grenada. Compared to Grenada soils, the St. Vincent soils had less potassium containing minerals; the main minerals identified in the St. Vincent soils were pyroxenes, plagioclase, olivine and magnetite with pyroxenes and plagioclase being more abundant. St. Vincent soils contained a very high content of fresh minerals. Some were more weathered than others, and in this situation a steady enrichment of the soils with released bases would be expected. The available nutrients in the soils could be described as medium high. In the minerals the potassium is probably in the form of accessory potash in the plagioclase felspars and phosphate is probably concretionary in all of them.

From the reserves of primary minerals present, it was probably safe to say that the St. Vincent soils which never had large sale applications of fertilizer or artificial manures prior to 1934, would be able to maintain a good level of fertility for a long time, without the use of these amendments. This prediction is well

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borne out by this present study and experience gained in soil fertility maintenance since that time to the present.

Hardy, F. 1939. Soil erosion in St. Vincent, B.W.I. Trop Agric. (Trinidad) 16: 58-65. (See Attachment 7).

The major soil groups were described according to the information which was available at that time. The problems of soil erosion were related to the two distinct types of land on the island namely, relatively recent volcanic ash where the soil profile was scarcely developed and the yellow earth soils which had welldifferentiated profiles. In each case, the land was very steep, up to 45 degrees.

In the recent volcanic ash areas, stabilization of the soils were achieved through the establishment of vegetation. Where crops were grown, the only practiced method was the construction of contour ridges upon which the crops were planted. To prevent accelerated soil loss, the aim should be to allow water to run away without impedance, while greatly reducing its flow over the soil surface and therefore continuous ridges could be counter-productive.

The yellow earth soils exhibited somewhat different erosion phenomena and presented other problems of soil conservation. The chief physical features that differentiate them from the recent ash soils were (a) the occurrence of partially cemented subsoils at varying depths (b) variable, but greater imperviousness to water (c) their lesser degree of stoniness and (d) their greater content of humus.

Various combinations of these factors appeared to decide the degree and kind of erosion which were characteristic. Sheet erosion was potentially serious.

Terracing would probably not prove to be satisfactory. It was suggested that barriers of woody plants and tussocky grasses would merely impede the run-off and encourage water-logging. In some circumstances, a system of crop rotation involving grass leys might prove suitable.

Where arrowroot was grown, good fertility management to achieve a ground cover as soon as possible after crop planting was proposed.

The prevention of hill-creep which resulted from the thorough saturation by water during periods of long continued heavy rains would seem to be mainly a question of the provision of adequate drainage.

Individual efforts to control erosion were likely to be ineffective; a cooperative approach was recommended.

The observations and suggestions by Hardy formed the basis for subsequent organized soil conservation work in St. Vincent but such work was not sustained.

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Hardy, F. and Cripps, E.G 1944. Subsoil fertility of eroded volcanic ash in St. Vincent, B.W.I. Trop.l Agric. (Trinidad) 21: 30 - 39. (See Attachment 8) It was previously found from field experiments on badly eroded hill-slopes that sulphate of ammonia alone increased the yield of arrowroot by 21 to 57 percent, of seed cotton by 35 percent and of sugarcane by 20 percent. In order to further test the fertility status of subsoils exposed by erosion, samples representative of the main agricultural soil types in this case recent volcanic ash, yellow earth and terras (cemented ash) were subjected to chemical and physical analysis and to pot test using sudan grass (Sorghum arundinaceum var. sudanense) to assess the fertility levels of the soils.

It was found that apart from an obvious shortage of nitrogen, the three subsoils were found to be deficient in available phosphorus although the recent ash showed a high phosphate content by chemical analysis. Available potash also proved to be inadequate except perhaps in recent ash but potassium fertilization conferred no benefit in any case unless accompanied by phosphate fertilizers.

The potassium status of the terras subsoil was somewhat higher than that of yellow earth subsoil. Based on the results obtained it was recommended that appropriate combinations of nitrogenous and phosphatic fertilizers be tested in field experiments for renovating eroded lands in St. Vincent and that the additional benefit which potassium fertilizers may confer be also further investigated. It was also suggested that leguminous cover crops to provide nitrogen to succeeding crops are also assessed.

This research is very important and significant and can provide base-line information if and when attempts will be made to rehabilitate badly degraded soils.

These results support the conclusion that the exceptionally high fertility levels which now obtains in many of the agricultural soils of St. Vincent is due to good soil management practices and generous use of fertilizers. There is only limited fertility which is inherited from the soil parent materials. This, however, is an important source of contribution to soil fertility and it is due to the high content of fresh mineral grains in all parts of the profile and the contributions from ash falls of succeeding volcanic eruptions.

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Hardy, F. 1945. Geology and Soils of British West Indies (i) St. Vincent; (ii) Grenadines. In F. Hardy 1945. Geology and Soils of the Caribbean Region.

Revised Edition. Mimeo Report. The Imperial College of Tropical Agriculture, Trinidad. (See Attachment 9) These notes represent a good summary of the then available information on the geology and soils of St. Vincent and Grenadines that was available at the time.

The publication and the references given, influenced subsequent work on the soils of these islands. Since the publication dealt with St. Vincent and the Grenadines specifically and not together with the other volcanic islands, it has special value.

Vernon, K.C. 1951. Soil survey report of Camden Park Experiment Station, St. Vincent. In: K.C. Vernon: AICTA Thesis.

Imperial College of Tropical Agriculture (ICTA), St. Augustine, Trinidad. Library, U.W.I. 47 - 66. (No attachment) This report records the results of a soil survey of Camden Park Experiment Station. The soils are briefly and incompletely described and there is limited and out-dated analytical data. The accompanying maps showing the distribution of the soils, land use and topography are no longer available. This report was disappointing in content and depth of information and it is only of historical importance.

Hardy, F. 1947. Phosphate deficiency in some West Indian soils as revealed by pot tests. Trop. Agric. (Trinidad) 26: 85 - 92. (See Attachment 10) In this study, pot tests were used with tomato as the indicator plant to assess the status of available phosphorus in some St. Vincent soils. This was a useful piece of work which was carried out before the spread of the banana crop and therefore before high levels of fertilizers were applied on the soils of St. Vincent.

It was found that both the high and low level yellow earth soils were phosphate deficient as indicated by the tomato plant. When phosphorus was added, the plant responded positively; nitrogen in addition to phosphorus further increased yields; potash alone did not influence plant growth but when added with nitrogen and phosphorus, there was some response.

In the soils of the flat low-lying areas, normally used for sugarcane and arrowroot, there was no response to added phosphorus.

For the volcanic ash soils, the tomato test plant showed marked phosphate shortage even though chemical soil tests indicated adequate levels. Therefore these soils would be expected to respond greatly to relatively large dressings of 10

phosphate when accompanied by additions of nitrogen. Nitrogen alone in the absence of phosphate would not be expected to confer maximum benefit.

Within the limits of the few soils studied, the work can nevertheless serve as a bench-mark for phosphate availability in St. Vincent soils before the advent of high dressing of fertilizers in the production of banana.

Hardy, F. and Beard, J.S. 1954. Soil formation in the British Caribbean Islands.

Department of Chemistry and Soil Science, The Imperial College of Tropical Agriculture, Trinidad. Mimeo Report 23 pp and maps. (See Attachment 11) This was a State of the Art account of the soil and land use conditions in the volcanic islands (Dominica, Grenada, St. Lucia, St. Vincent, St. Kitts and Monsterrat) available at the time of the publication. The occurrence and soil behaviour of the soils of the various islands were compared and contrasted and a basic classification of the soils was introduced.

This publication greatly influenced the subsequent Soil and Land Use Survey of St. Vincent (Watson et al. 1958). However, it lacked details in all respects and therefore it could not influence to any extent, use and management of the soils.

Watson, J.P., Spector, J. and Jones, T.A. 1958. Soil and Land Use Surveys No. 3 St. Vincent. The Regional Research Centre, Imperial College of Tropical Agriculture, Trinidad, W.I. (See Attachment 12) This is the basic and fundamental report on the classification, distribution, land capability and land use of the agricultural soils of St. Vincent. The soils were mapped on 1:20,000 scale on an outdated topographic map and were classified up to the series level, 50 soil series being identified. The overall classification used was that proposed by Hardy et al. (1934). The report was summarized as follows by Ahmad (1984): St. Vincent is entirely of volcanic origin. There is a central range of hills in a north-south direction which are really volcanic cones of varying ages but not earlier than the Pleistocene. The rocks are mainly agglomerates, lavas and finer pyroclastic volcanic materials, all of basaltic or andestic mineralogy.

The landscape is influenced by a number of former marine terraces which represented various stages of uplift of the island. Marine erosion has resulted in rolling landscape which is best seen on the eastern side of the island. On the western side, the topography is more youthful and steeper.

The climate of St. Vincent can be described as generally humid. The Central Highlands receive on the average over 3,750mm of precipitation with no dry 11

months. The rainfall decreases all around the island concentrically as the land level drops, and on the lowest areas on the periphery, only 1,500mm is received with 4 - 6 dry months. The main agricultural areas receive about 2000 - 2500 mm of rain per year with 1 - 3 dry months. In the average year, therefore, moisture deficiency is not of great limitation for agriculture.

Another element of climate affecting agriculture is wind direction and velocity.

The fairly strong and continuous prevailing north-east winds make the eastern coastal areas less suitable for some of the crops which are important such as banana, cotton and cacao.

Natural vegetation presently exists only on the central mountains and since this is the wettest part, the vegetation is tropical rain forest. The rest of the island is mostly in secondary vegetation and the types and associations are in accordance with the zonation of the rainfall.

Analysis of the report: The main virtue of this report is the mapping of the soils which was accurately done to the scale. The soil horizon/layer descriptions, are, on the other hand, incomplete. The maps are difficult to read due to insufficient and inaccurate topographical features. Moreover, the paper on which the maps were printed are now brittle and while there are still a few of the reports to be seen, the maps are no longer available and this is a cause for much concern. Urgent steps should be taken to have the maps reprinted on a standard topographic map at 1:25,000 scale.

The land capability assessment presented in the report has been wholly based on the USDA system without any modifications or adaptations to local conditions.

Therefore, the suitability of the soils for mechanized agriculture and therefore the angles of the slopes were the main criteria for the classification. No cognizance was taken of the fact that mechanized agriculture would never be important in St. Vincent. The land capability classification presented in the report was not corroborated with field conditions and indeed a map showing the land capability classes was not prepared. In the whole area of land capability classification, therefore, the report is very deficient.

The soil analysis data in the report is presently almost meaningless. Most of the parameters measured are no longer used in assessing soils and most soil scientists and agronomists cannot now interpret them. They represent a very incomplete and out-dated characterization of the soils.

In the report itself there are some important hidden errors. No descriptions and analytical data have not been presented for soils Nos. 30, Soufrière Cindery Gravelly Loamy Sand (excessively cindery variant), 32 Soufrière Cindery Gravelly

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Sandy Loam and Cindery Gravelly Loamy Sand (alluvial-colluvial variant) and 41 York Sandy Loam and Sandy Clay Loam (imperfectly drained variant). No account of these omissions were taken in presenting the information in Appendix D of the Report i.e. Soil Profile Descriptions and Analytical Data. There is no problem with the information for soils 1 - 29, but after this the numbers given for the soils are incorrect and misleading. The soils are correctly listed in Appendix A - The Soils of St. Vincent - Some Important Characteristics and Recommendations for Optimum Land Use. In the title of this Appendix, the bracketed information i.e. (see page 39) - is meaningless.

In summary, it is very appropriate for the soil survey of St. Vincent to be repeated and soil conditions in the central part of the island which was not surveyed by Watson et al. (1958), be included.

Wright, A.C.S. 1959. A New Zealand Pedologist in the Caribbean (November 1958 - March 1959). V. St. Vincent. Mimeo report. Restricted circulation.

(See Attachment 13) This report presented the observations and insights of an experienced pedologist from New Zealand on soil formation and soil conditions in selected Caribbean territories including St. Vincent. The report largely supported the findings and conclusions of Hardy et al. (1934) and Watson et al. (1958). However, some analytical data were presented to show that the potassium reserves in the soils were not substantial compared to many other Caribbean soils. Therefore the sustained use of potassium containing fertilizers in St. Vincent agriculture was well founded.

Hay, R.L. 1960. Rate of clay formation and mineral alteration in a 4000 year old volcanic ash soil in St. Vincent, B.W.I. Amer. Jour. Sci. 258: 354-368. (See Attachment 14) Through radio-carbon dating, the surface of a large fan of pyroclastic deposit erupted about 4000 years ago has weathered to a clay soil of about two metres thick. The weathered deposits were originally andesitic ash consisting largely of glass and the minerals anorthite, labradorite, hypersthene, augite and olivine.

Fine vitric ash has weathered to halloysite, allophane and hydrated ferric oxide.

The vitric lapilli were decomposed to halloysite. Anorthite crystals in the soil were etched and frosted in the underlying soil. Many hypersthene and fewer augite and olivine crystals in the soil were etched, clearly showing the results of weathering. Labradorite, hornblende and magnetite were unaltered.

The 4000 year old soil represents an early stage in the formation of the yellow earth soils of St. Vincent which may be classified with the yellow-brown volcanic ash soils of Japan.

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Clay soil formed from ash at an average rate of 45 to 60 cm/100 years on St. Vincent and glass decomposed at a rate of about 15g/cm2/1000 years. The slight degree to which the unstable minerals anorthite, olivine and the pyroxenes were altered contrasted sharply with the decomposition of the glass. There is evidence suggesting that mineral grains have altered more rapidly in some podzols of the temperate regions than in volcanic ash soils of St. Vincent. This contrast in weathering rate may perhaps be explained by the low pH of podzols and the chemical effect of the rapidly decomposing glass of the ash soils.

This is a significant study which showed that the fine volcanic ash weathers quite quickly in the St. Vincent environment, thus contributing to the maintenance of soil fertility. Thus, the relatively light ash showers from the periodic eruptions on the island may be a very important aspect of soil fertility maintenance.

Cochrane, T.T. 1962. A study of the land use potential of two of the major soil types of St. Vincent, the high level yellow earth soils and the recent soils from volcanic ash. AICTA Thesis. Imperial College of Tropical Agriculture, St. Augustine, Trinidad 353 p. (See Attachment 15) The thesis consists of two main sections and several sub-sections. The first section (Section A) dealt with the soil survey report of the island by Watson et al.

(1958) which was first published at that time. No significant new information was given.

Section B presented results of field fertilizer experiments and greenhouse experiments on the fertility assessment and requirements of the soils. In general, the soils responded to phosphorus applications but for sweet potato, there was a negative response to nitrogen. For the Montreal soil a response to lime was obtained.

The thesis has an appendix consisting of a comprehensive review of all past fertilizer trials which were conducted by the St. Vincent Department of Agriculture. Arrowroot, cotton and sugarcane were considered individually and a section was included for other fertilizer and manurial experiments.

This is a very verbose document (353 foolscap pages) with information too diluted. A useful part is the summary of all fertilizer experiments and associated references which are given in this report an attachment 15.

Those experiments conducted on cotton and sugarcane are not given because they are no longer commercial crops in St. Vincent and in any event, permission was not obtained to have the copies made.

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Regional Research Centre (RRC). 1962. Report on Soil Research. Mimeo report. Soil and Land Use Section, The University of the West Indies, St. Augustine, Trinidad. 18p (See Attachment 16) An experiment was conducted to assess the response of the “creole” and “banana” varieties of arrowroot to applications of a 16:8:16 NPK fertilizer blend of up to 2500 kg/ha. For the creole, the yield increased from 14,825 kg/ha of rhizomes at the zero level to 29,175 kg/ha at the 2,500 kg/ha level of the fertilizer application; for the banana variety, the corresponding values were 18,475 kg/ha and 33,325 kg/ha. Banana out-yielded creole at every fertilizer level. The results further suggested that very little extra yield could be obtained by increasing, still further, fertilizer applications on creole though it might very well be with banana.

Regional Research Centre. 1962. Banana investigations. Mimeo Report. Soil and Land Use Section. The University of the West Indies, St. Augustine, Trinidad, W.I. 37p (See Attachment 17) This report contains the following sections which are concerned with soils and fertility maintenance with respect to banana cultivation. (i)

(ii)

(iii)

Soil analysis of soils from several sites on which fertilizer experiments were established – the results contrasted greatly with the present levels of soil fertility, the current values for the nutrients being much higher. This is as a result of continued use of fertilizer on these soils since 1962.

Leaf analysis: The aim of this study was to establish the most nutrient sensitive part of the plant to analyse for diagnostic purposes as well as to establish critical ranges of the nutrients to indicate satisfactory levels for good nutrition. These results were later published (i.e.

Twyford and Coulter, 1964; Twyford, 1967).

Uptake of 32P by banana: The radio-active phosphate distributed itself more evenly with the non-active phosphate in the plant in the younger stages of growth but at the fruiting stage there was a tendency for the fertilizer phosphate to appear preferentially in the leaves. The young, unemerged leaf tissue of small plants was the most sensitive material to use in the detection of the entry of radio-active phosphorus into the banana plant. The corm, leaves and pseudostem accumulated the bulk of the added phosphate except that in the fruiting plant a high percentage was in the fruit.

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Regional Research Centre. 1962. Arrowroot investigations. Soil and Land Use Section. RRC, U.W.I. St. Augustine, Trinidad. (See Attachment 18) A research programme on arrowroot to assess the role and crop response to fertilizers on different arrowroot growing soils was outlined but no record could be found that the work was actually done. If in fact the planned research was not carried out, the programme as outlined is still relevant in an improved arrowroot industry and it should be implemented.

The agreed programme for agronomic research was as follows: (i) 1962-3: Factorial trial to determine the optimum, i.e. most profitable, individual dressing of nitrogen, phosphate and potash fertilizers (separately), based on the high levels shown to be promising in the 1961-2 experiment at Union Estate for Banana arrowroot. This is to include testing how much of each fertilizer should be applied at planting and at three months after planting. The object of the trial is to find the best mixture and time of application for the poorer parts of the Low Level Yellow Earth. (ii) 1962-3: Trial to determine the optimum dressing of 16:8:16 fertilizer for creole and banana arrowroot on recent soil from volcanic ash, applied broadcast at three months. This trial is a repeat of the 1961-2 Union Estate trial on the other chief arrowroot-growing soil. (iii) 1962-4: Trial to test the effects of a wide range of planting times on growth and yield of banana and creole arrowroot. This is to include a study of the ripening process in the two varieties as measured by starch content. (iv) 1963-4: Trial on fertilizer placement versus broadcasting. (v) 1963-6: Trial on the residual effects of high levels of fertilizers on following crops and on the soil. (vi) 1963-4: Trial to test the effects of further splitting fertilizer dressings to include a very late application, using both creole and banana and with planting times spanning the whole normal period. This may be useful deliberately delaying ripening so as to maintain high starch content until late in the digging season. (vii) 1964-5: Simple fertilizer trials on several farms covering the whole range of soils normally used for arrowroot and based on the results of experiments (i) and (vi). (viii) 1964-5: A trial on the best spacing of banks and the amount of ‘bit’ planted in the bank. This may be affected by the rate of fertilizer dressing. Past experiments on this problem have been carried out using flat planting. (ix) 1964-5: A trial on the effects on yields and soil of nitrogen from various fertilizer source.

16

(x)

1963-4: Determination of total nutrient uptake by the arrowroot plant by periodic chemical analysis.

Trials on weed control by herbicides and on methods of defoliation before harvesting should be carried out as opportunity offered. Pot studies should also be carried out on the physiology of development and growth of the arrowroot plant under various conditions.

Moss, P. and Coulter, J.K. 1964. The potassium status of West Indian soils.

Jour. Soil.Sci. 15:284 - 298. (See Attachment 19).

In this study, the potassium status of selected soils from Barbados, Dominica, Grenada, St. Vincent, St. Lucia and Monsterrat were studied. For St. Vincent, low level yellow earths sampled at Rutland Vale, Union, Belle Isle and Queensbury, shoal soil sampled at Camden Park and a volcanic ash soil from the Soufrière District were included in the study. The sites unfortunately were not correlated to any particular soil series. Unfertilized soils were used in the study which included an examination of the intensity, exchangeable, nitric acid soluble, fixation and total potassium values. Total potassium in the soils averaged 0.38 percent. Neither potassium highly soluble in nitric acid nor that of limited solubility were related to percentage clay but both were highly correlated with total potassium. Fixation of added potassium was low, a result also obtained by Prashad (1969). The ratio of potassium to calcium and magnesium was highest in allophanic (yellow earth) soils and lowest in montmorillonite soils (shoal); it was correlated with exchangeable, fixed and highly correlated with exchangeable potassium.

This research showed that for the St. Vincent soils, fixation by the soil of applied potassium is not a problem. In fact, Prashad (1969) showed that under some conditions, application of the nutrient could result in its release from reserves, probably resulting from increased oxidation of organic matter. In these soils, it is the ratio of the cations potassium, calcium and magnesium which may be more important in plant uptake of potassium.

This is a good piece of work but would have been more useful if the soils sampled and studied had been identified and the series names given; the results were also confounded with those of the soils of the other islands.

17

Twyford, I.T. and Coulter, J.K. 1964. Foliar diagnosis in banana fertilizer trials.

In: C. Bould, P. Prevot and J.R. Magness (eds.). Plant Analysis and Fertilizer Problems. 4; IRHO, Paris, 357-370. (See Attachment 20).

Experiments to develop a diagnostic leaf sampling technique in Robusta banana were described. Considerable differences in nutrient concentration were found on opposite sites of sections of the lamina and along the lamina length.

Differences were smallest near the middle of the leaf. Using middle sections, the effects of leaf age were studied. Nitrogen increased to a maximum at about the third or fourth fully opened leaf then declined with increasing leaf age.

Potassium declined very markedly from the youngest to the oldest leaf.

Phosphorus declined less so but in the same direction. Calcium rose markedly from youngest to oldest leaf and magnesium less so in the same direction.

Stages of plant growth were divided into small (90 - 120 cm high), medium (120240 cm high), large (well grown but not yet ‘shot’) and ‘shot’. Medium and large plants did not differ significantly in nutrient content; values for small plants were higher for nitrogen, phosphorus and potassium but similar for calcium and magnesium, whilst values for ‘shot’ plants were generally lower than for the preshooting stage for nitrogen, phosphorus and potassium, higher for calcium and not different for magnesium.

The effects of time of sampling in the day were variable but rather small for large plants. Interactions between the above factors chiefly affected leaf potassium and were most favourable particularly in early mature leaves (leaves 3 or 4 from the youngest). Coefficients of variation were rather high especially from plant to plant.

A tentative sampling technique was suggested, using material taken from both sides of the middle portion of the lamina of the fourth leaf, counting from the youngest (at least partially unfurled) and bulking samples from several similar plants.

Ten 3x3x3 NPK factorial experiments were sampled and the results used to try to estimate adequacy levels for nitrogen, phosphorus and potassium.

For nitrogen and potassium, addition of fertilizer resulted in considerable increases in mean leaf concentration, but increases due to phosphorus were small and irregular. Considerable fertilizer - leaf level interactions occurred and it was necessary for estimation of adequacy to use only those plots lacking only the particular nutrient.

18

Responses to nitrogen fertilizer occurred at all sites, to potassium at 8 and to phosphate at 4 out of 10. Some evidence of luxury consumption emerged and thus for adequacy levels only the leaf contents for maximum growth with the lowest level of fertilizer should be used. Using these considerations, an adequacy limit for K at about 3.8% potash was set, for nitrogen the optimum limit was about 2.9% nitrogen, but two very light soils gave a level of 2.6%. In these soils, there may be a different nutrient balance at maximum growth. For phosphorus, the critical level varied from 0.29 - 0.48% phosphate. Below 0.25% plants appeared always deficient and above 0.43% always adequate. Further work is thus required on leaf phosphorus but fortunately phosphorus deficiency is easy to detect in the field.

Soil analyses indicated that 0.41% of total nitrogen was inadequate for the nitrogen nutrition of banana, that the adequacy level for exchangeable potassium lay between 0.31 and 0.42 cmol/100g soil, provided there were no other important soil sources of supply, and that the critical level for Truog phosphate was between 7 and 32 p.p.m. phosphate.

WINBAN NEWS. 1965. Growing resistance to new fertilizer formula in St. Vincent. WINBAN News Feb - April, 1965: 33 (See Attachment 21) WINBAN 1990. Fertilizer use in banana production. Fact Sheet. Windward Islands Banana Growers Association Research and Development Division Communications and Documentation Unit, Roseau, St. Lucia. (See Attachment 54) The first leaflet reported that St. Vincent farmers expressed dissatisfaction over the new fertilizer (12:4:30 NPK) being introduced on the basis that it did not have as much nitrogen as the formerly use product (16:8:16 NPK). Additionally, the new fertilizer was lumpy and it was not as easy to use as the old one. The new fertilizer apparently produced better quality fruit and farmers were advised to use it and apply side-dressings of nitrogen fertilizers such as ammonium sulphate or urea additionally.

The second leaflet presents detailed instructions with diagrams on how to apply the fertilizer - times, rates, frequencies and method. Blends of 16:8:24:2 (NPK + MgO) or 16:8:24 were recommended.

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Partridge, I.J. 1965. A review of fertilizer experiments on food crops in the British Caribbean Territories 1935 - 1965. Diploma of Tropical Agriculture (DTA) Thesis. Library, The University of the West Indies, St. Augustine, Trinidad. (No attachment) During the period under review 23 experiments were conducted in St. Vincent to assess the response of food crops to fertilizers. The number of experiments and crops on which they were conducted were as follows: Arrowroot Banana Cassava Groundnut Black-eye pea Maize Sugarcane Sweet potato In sixty-three percent percent to potassium experiments were all Annual Reports for the

3 9 1 3 1 1 2 3 of the experiments there was response to nitrogen, 45 and response to phosphorus was inconclusive. These reported in the St. Vincent Department of Agriculture period under review. (See also Cochrane, 1962).

The experiments were not always scientifically planned and conducted.

Additionally, since they were carried out, there has been major increases in soil fertility levels due to sustained high applications of fertilizers. Therefore experiments on fertilizer use for the important crops, especially the root crops, should be carried out with improved planning and management. This is a prerequisite to developing a programme for improved production of these crops. It is also important to establish a fertilizer use programme based on results of soil analysis.

Twyford, I.T. 1967. Banana nutrition: A review of principles and practice. J. Sci. Fd. Agric. 18: 177 - 183. (See Attachment 22) This publication presented basic information on nutrient content and nutrient removal by single banana plants, fields of plants and bunches of banana as the basis for determining fertilizer requirements in the field. Time and frequency of fertilizer application and placement of such fertilizers were discussed in relation to fertilizer use on the crop.

From experience up to the time of writing, any soil with less than 15 parts per million of phosphorus (presumably by Truog’s method although this is not 20

stated) was considered deficient and below 25 parts per million as suspect.

Among the exchangeable bases, potassium values lower than about 0.45 cmol/kg soil were usually from deficient soils as were magnesium levels below about 0.8 cmol/kg soil. Presently, the adequacy of the cations are more commonly assessed on the degree of cation saturation of the cation exchange complex of the soil.

Standards for leaf composition of the major nutrients were established based on the analysis of the fourth youngest leaf of plants of ages ranging from two months before shooting to just before shooting. The critical level for nitrogen was shown to be 2.9 percent on most soils and 2.6 percent on very lighttextured soils; for phosphate (P2O5) it was 0.29 to 0.48 percent, and for potash (K2O), 3.8 percent (see also Twyford and Coulter, 1964).

Deficiency symptoms of the major nutrients were also described. This paper presented a considerable amount of information and summarized data on the nutrition of the banana crop and implications for fertilizer use.

Walmsley, D. and Twyford, I.T. 1968. The zone of nutrient uptake by the Robusta banana. Trop. Agric. (Trinidad). 45: 113 - 118. (Attachment 23) As a guide to efficient fertilizer usage with Robusta banana, it was important to determine the feeding zone in the soil of this variety. In order to determine the zone of nutrient uptake, ratio-active isotope of phosphate was placed at various distances from the stem of the plant and the uptake of the nutrient in a particular region was confirmed when the isotope was detected in the leaf tissue of the growing plant.

An experiment was conducted in St. Lucia and in St. Vincent to obtain this important information. The plants used at both locations were in their late vegetative or early fruiting stage of growth when the root systems were fully developed. Only minimal damage of the roots by nematode was observed.

Based on the results, it was recommended that since in the Windward Islands banana is planted at a spacing of 2.4m x 2.4m or closer, feeding roots extend throughout the whole of an established field. Consequently, there would be no advantage in placing fertilizer separately around each plant as was the common practice; it could most usefully be applied at this stage by broadcasting it over the whole field or placing it in convenient bands between the rows.

In a newly planted field, fertilizer applied at one month should be kept within a circle of 30 cm radius around the plant and at two months, up to one metre radius. Later applications could be broadcast.

21

Obviously, this was a useful research project, as it provided key information on where to apply fertilizers as the banana crop keeps growing and developing.

There is little field evidence that the recommendations are being followed at this time, particularly with respect to the fertilizer application at the later vegetative or easily fruiting stages of crop development.

At the time the experiment was carried out the popular fertilizer used on banana was a 12:4:30 NPK blend.

Prashad, S. 1969. Physico-chemical properties of Caribbean Andepts with reference to potassium and ammonium fixation and release. M.Sc. Thesis, Department of Soil Science, The Library, The University of the West Indies, St. Augustine, Trinidad. (Attachment 24) The study investigated the following: (a) A method for dispersing clays of Caribbean Andepts to allow particle size analysis and particle fractionation. (b) Cation exchange properties under various conditions, i.e. various pH levels, strengths of leaching agent and washing techniques. (c) The behaviour of potassium and ammonium in the laboratory under various conditions - moist fixation or release of potassium and ammonium nitrogen at varying levels of application from potassium chloride or ammonium chloride; effect of drying (air and oven) soil previously at 30 percent moisture content on the fixation or release of potassium; effect of ammonium ions and pH on the moist release of potassium; moisture content on release or fixation of potassium; potassium release after prior removal of water soluble and exchangeable potassium and potassium fixation in organic matter free soil when applied in varying levels as potassium chloride. (d) Effect of applied potassium and nitrogen on the dry matter yield and uptake by Sudan grass in the greenhouse.

Soils for these investigations were obtained from St. Vincent and Dominica in Montreal and Boetica soils. These soils are classified as yellow earths and have been formed on volcanic ash deposits on the islands.

Results of the above investigations showed that: (a) Methods used by workers elsewhere were unsuccessful in causing complete dispersion in both soils. Zirconium nitrate solution was found to be a successful dispersing agent. 30ml of 0.1 molar zirconium nitrate solution was necessary to cause complete dispersion of 10g samples of both soils. The extent of dispersion was compared using centrifuge and pipette methods. These agreed very well.

22

Dispersion of clays was due to an increase in the overall positive charge on clays.

Some aluminium was replaced by zirconium, resulting in an overall positive charge.

Mechanical analysis of the soils indicated a high percentage of coarse sand in the Montreal soil and lower in the Boetica soil. Organic matter content in both soils was quite high, that of Boetica soil being higher.

Clay content was also higher for the Boetica soil. The soils had higher sand and organic matter fractions than indicated by field examination. (b)

The cation exchange capacity of both soils showed peculiarities observed in allophane type soils of temperate regions.

Cation exchange capacity increased with increasing concentration of leaching agent, increasing pH, and washing with alcohol alone. However, the cation exchange capacity decreased when water was used as a washing agent prior to the use of alcohol.

The high cation exchange capacity values obtained for alcohol-washed samples indicated that a large quantity of cations was held purely by physical (non-coulombic) surface adsorption.

These were easily removed by water (a polar solvent). The remaining cations were held by electrostatic (coulumbic) forces and constituted the stronger cation retention system. Because of the easy removal of cations by water, these soils may easily lose nutrients (potassium and ammonium and most likely also calcium and magnesium) through leaching under field conditions.

(c) (i)

(ii)

(iii)

Laboratory experiments showed the following: The moist incubations of both soils caused release of potassium. The higher the level of application the greater was the release. Release, however, was not uniform and showed no definite trend or sequence.

The same applied for the NH4 treatments. Ammonium was released but no set pattern could be observed.

Ammonium ions applied in several ratios with potassium ions, did not seem to have any appreciable effect on the release of potassium at the 100 and 1000 parts per million potassium and ammonium levels.

However, potassium release decreased as the potassium:ammonium ratio of application fell for 100, 1000 and 10,000 parts per million levels. At the 1:1 ratio the application of ammonium resulted in lower release of potassium than if potassium were applied alone in Boetica soil.

Air-drying Montreal soil at the end of the first month caused release, while oven-drying caused release of potassium only at higher levels of

23

potassium application (500, 1000, 5000, 10,000 p.p.m.) Slight fixation was observed in all air-dried samples and for 0, 100 and 500 parts per million applied potassium, for oven-dried samples.

(iv)

(v)

(vi) (vii)

(d) (i)

(ii) (iii)

(iv)

Fixation in Boetica soils was observed from 0 to 1000 parts per million applied potassium at the end of the first and second months, for both air and oven-dried samples. However, release was high for the other treatments, this release decreasing towards the end of the second month.

In the Montreal soil, ammonium chloride extractable potassium values for the three pH levels (5.4, 5.8 and 6.3) studied, were higher than for normal soil pH levels. The values at the three pH levels tended to remain constant over a three-month period. Release of potassium decreased as pH increased. Boetica soil showed similar properties.

Decreasing potassium release occurred with increasing pH and the exchangeable potassium values tended to be constant over a threemonth period for the three levels.

At 10 and 20 percent moisture contents, potassium was fixed in small quantities at low levels of potassium application. At higher levels, potassium was released after a gradual decrease in fixation as in Montreal soil or immediately as in Boetica soil.

Potassium release after prior removal of exchangeable potassium, indicated that only small amounts actually came from the inorganic fraction.

Organic matter removal and subsequent treatments with varying levels of potassium resulted in potassium fixation in small quantities, the maximum being 55 parts per million in Montreal and 60 parts per million in Boetica soils.

Greenhouse trials gave the following results: Both nitrogen and potassium applied to Sudan grass had high significance (p<0.01) on yield, that of potassium being higher than nitrogen. The interaction of nitrogen and potassium was also highly significant (p<0.01).

The application of nitrogen was highly significant in nitrogen uptake by the grass (p<0.01) while applied potassium was less significant (p<0.1) in affecting nitrogen uptake.

Nitrogen was not significant in potassium uptake by the plant.

However, potassium applied caused significant (p<0.01) uptake of potassium. Nitrogen-potassium interaction for potassium uptake was insignificant.

The application of nitrogen to the soil caused a yield response by the grass even at 1000 parts per million of N applied. For potassium,

24

response occurred at first then leveled off after about 400 parts per million applied potassium.

The practical and theoretical implications of this work were discussed. Organic matter oxidation was the source of potassium and nitrogen release in these soils.

The higher level of potassium or ammonium applied, the greater was the release. Added potassium and ammonium seemed to have some effect on the release of potassium and nitrogen from these soils. In the laboratory, on the application of potassium chloride and ammonium chloride at optimum moisture conditions, breakdown of organic matter and release of nitrogen and potassium were apparently stimulated.

Organic matter content in these soils is quite high and it is a great asset that its breakdown is not rapid. As was observed, the majority of potassium and ammonium ions were leached out with water in cation exchange capacity determinations, hence if great quantities of potassium or nitrogen were released at any time, the inorganic fractions of the soils would not have the power to retain these in any fixed state. However, slow release from organic matter is a good way of overcoming this problem. This partially explains why plants growing on these soils thrive well although the soil fertility status as regards cation retention power is very low. Any fertilizer application should be split to minimize leaching losses through these free-draining soils.

Messing, J.H.L. 1969. Indications of sulphur deficiency in Windward Islands soils. Proceedings of a Soils Seminar held at UWI, Cave Hill, Barbados 29 - 30 May, 1969: 1 - 8. (See Attachment 25) It was increasingly being recognized that banana was not growing as well as might be expected in spite of adequate applications of nitrogen, phosphorus and potassium and there were no obvious other limiting factors such as light, water, and unfavourable soil physical conditions. A pale colour developed in the youngest leaf which was confused with magnesium deficiency and which was corrected with dressings of kieserite (magnesium sulphate). The plants were sprayed with 4 percent magnesium sulphate and kieserite was applied to the rate of 112 g per plant. The plants recovered completely and produced normally.

Mild magnesium deficiency was also involved but this was due to overapplication of potassium.

In St. Vincent, pot experiments aimed to assess response to sulphur involving both low level and high level yellow earths were carried out; tomato and chinese cabbage were used as test plants. It was found that when sulphur was not supplied, both crop plants could not make any growth. For banana not only growth and production of the crop was adversely affected by lack of sulphur but also the quality of the fruit.

25

The problem of sulphur of deficiency in some of the banana soils of St. Vincent was also found by WINBAN (1970) and ul Haque (1971).

Walmsley, D., Cornforth, I.S. and Ahmad, N. 1969. Methods of estimating available nutrients in Windward Islands Soils. Department of Soil Science, University of the West Indies, St. Augustine, Trinidad. Report No. 15 (Attachment 26) The purpose of this investigation was to select analytical methods for estimating soil nitrogen, phosphorus and potassium which were most successful both in predicting yield responses to fertilizer applications and nutrient uptake. This step was considered essential as a pre-requisite to establishing a rational fertilizer advisory service based on soil analysis. Maize was used as the test crop in greenhouse experiments. Bulk soil samples (0 - 30 cm) were collected, five from St. Vincent, six from Grenada, eleven from Dominica and nine from St. Lucia and used in the experiments.

Available phosphorus was estimated using nine methods; available nitrogen was estimated by incubation and chemical methods and available potassium was determined using five methods. Dry matter yields and nutrient uptake were correlated with the soil test results in order to recommend the most efficient methods for extracting the available forms of the various nutrients. The results were as follows: 1.

Nitrogen: (a) Correlations between test value and percent yield: The chemical estimates of available nitrogen were superior to the incubation techniques in predicting the response of maize grown in these soils to nitrogen; of the chemical methods, nitrogen hydrolysed by 1.0 N hydrochloric acid or by 1.0 N sodium hydroxide solution was best correlated with percent yield. Total soil nitrogen was also significantly correlated with percent yield at the 0.1 percent level of probability. (b) Correlation between test value and nitrogen uptake: Nitrogen hydrolysed by 0.1N and 1.0N hydrochloric acid gave the best assessment of availability measured as nitrogen-uptake. Initial mineral nitrogen in the anerobic incubation test (ammonium nitrogen) was also correlated with nitrogen uptake; soil mineral nitrogen is not usually considered a reliable estimate of potential supply as its fluctuates rapidly in field conditions.

The relatively poor correlations between mineralizable nitrogen and yield or uptake data were because some of the soils from St. Lucia and 26

Dominica were stored in a slightly moist condition before being used.

Before the laboratory incubation these soils contained 59 and 81 ppm mineral nitrogen respectively compared with 27 and 20 ppm in the soils from Grenada and St. Vincent. Thus nitrogen must have been mineralized during storage. The effect of this on other estimates of nitrogen availability was not known.

It was intended that all methods of measuring available nitrogen will be further tested and calibrated with the results of field experiments.

2.

Phosphorus (a) Correlations between test value and percent yield: Olsen’s method using 0.5 N sodium bicarbonate extract gave the highest correlation with percent yield. Several other methods also gave highly significant correlations and Amer’s anion exchange resin was the best of these. (b) Correlations between test value and phosphate uptake: The methods of Olsen and Amer also gave the two best correlations with phosphorus uptake but here the order was reversed with Amer’s method somewhat superior to Olsen’s.

Since Olsen’s method also showed good correlations with soils from Jamaica, Barbados, Trinidad and Tobago (Department Reports Nos. 12, 13 and 14), it was tentatively proposed that this method should be used for routine soil analysis in the region. However, as was stated in previous reports, it was still necessary to confirm these results and calibrate the methods using data from field experiments.

3.

Potassium: The results showed that total potassium correlated very poorly with both potassium uptake and percent yield. The other methods tested correlated highly with potassium uptake and percent yield and there was virtually no difference among then for efficiency. This was so in spite of the fact that the extraction procedures ranged from the very drastic boiling nitric acid treatment to the mild ammonium acetate extraction.

The low values for total potassium and potassium extracted by the other methods are in accordance with the very good correlations with percent yield and with field response to potassium fertilizers on these soils. The work indicated that the soils of the Windward Islands would not fix fertilizer potassium in unavailable forms and therefore the potassium status of these soils, though low, must be regarded as highly available.

(See also Wright, 1959; Prashad, 1969).

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Ahmad, N. and Prashad, S. 1970. Dispersion, mechanical composition and fractionation of West Indian volcanic yellow earth soils (Andepts). Jour. Soil Sci. 21:63-71. (See Attachment 27) In this study a method for successful dispersion of allophanic soils (high level yellow earth) using zirconium nitrate solution as dispersing agent was developed and tested.

Methods for dispersion developed in Japan and New Zealand for allophanic soils which involved adjusting the pH of organic matter free soil suspensions to 4 or 10.5 were not effective on similar soils in the Caribbean. Partial dispersion was obtained by adjusting the pH to between 2 and 3 but lower (down to pH 1) and higher (up to pH 11.1) were ineffective. Substantial amounts of aluminium dissolved at pH 1 - 3 probably as a result of some disintegration of the allophanoid minerals.

Zirconium nitrate solutions were very efficient in causing dispersion, a concentration of 12 milli-equivalents zirconium being necessary for complete dispersion of 20 g samples of soil. Excess zirconium did not adversely affect dispersion but resulted in depression of pH of the suspensions. The high ionic charge, small atomic radius and low ionization potential of zirconium apparently resulted in saturation of the cation exchange capacity and some isomorphous substitution of aluminium leading to a net positive charge of the clay and increase in anion exchange capacity.

The significant increase in easily extractable aluminium from zirconium treated soils is further evidence of this.

As a result of being able to disperse the allophanic soils, accurate particle size analysis was carried out on Montreal, Greggs and St. Vincent loam for the first time. The dispersion also enabled other workers to separate the clay fraction for further study i.e. Macfarlane (1974).

WINBAN Windward Islands Banana Growers Association Research and Development Division 1970 - 1992. Annual Reports. WINBAN, Castries, St. Lucia. (No Attachments - Reports available in St. Vincent) Applied research on improving the efficiency of fertilizer use continued during this period based on the standards and norms established earlier by Twyford (1961), Walmsley and Twyford (1968) and Twyford and Coulter (1964). For instance it was found that the ratio of nitrogen, phosphorus and potassium in the plant tissue approximated 16:4:24 and therefore a fertilizer with this ratio of nutrients was manufactured and used throughout the Windward Islands. Later, a fertilizer providing some more phosphorus i.e. 16:8:24 was preferred and generally used. A pale colouring of the young leaves of growing banana which was probably due to sulphur deficiency was corrected by incorporation of two or 28

four kg/ magnesium oxide per 100kg of fertilizer and this fertilizer i.e. 16:8:24:2 or 4 MgO was routinely applied. The effect of this on the magnesium content of the soils was ignored.

Amount and method of application of fertilizer used: In early experiments it was found that 3 pounds/mat (1.36 kg/ mat) whether there were 680, 726 or 990 mats per acre (1680, 1792, 2444 mats/ha) was optimum and this was established as field practice.

No significant differences in yield were obtained in early experiments on broadcasting or placing of the fertilizer; in later experiments, better results were obtained with placement. Additionally, it was found that placement reduced toppling and produced better root systems and therefore placement was recommended and became standard practice. Details of fertilizer applications were given in WINBAN (1965), (1990).

Potential yield was better at 990 mats/ac (2444/ha) although economically, 680 mats/ac (1680/ha) was found to be better.

Criteria for fertilizer use: Soil and plant tissue analysis were routinely used as a check on fertilizer use. The standards, norms and critical levels of the major nutrients in both soils and plant tissue established in the early research of Twyford and Walmsley (1973), (1974), (1974) were used throughout.

The analytical values were used mainly to confirm that the levels were adequate or deficient and were not used to determine how much fertilizer to apply to the growing crop which was generally set at 3 lb/mat (1.36 kg/mat) in any event. It was found that when this level of fertilizer application was followed, plant tissue composition of the nutrients was in the adequate range. If this were not the case, the farmer was advised to increase his application rate.

Side dressing of nitrogen (0 - 90 gm/N/mat) or phosphorus and magnesium (0 64 gm/mat) produced no overall significant differences in yield.

Altering the nitrogen to potassium ratio of fertilizer did not increase bunch weight; varying potassium rates had an inconsistent effect on crop performance and the conclusion was made that altering the absolute or relative amounts of nitrogen and phosphorus within the levels in the blended fertilizer was unlikely to have any significant effect on yield. The indication is, therefore, that basing the composition of the blended fertilizer on the ratio of nutrients in the plant tissue was a good decision.

Fertilizer blends from five sources supplying nitrogen, phosphorus and potassium in the ratio 16:8:24 plus two or four magnesium were tested to indicate whether

29

any of them was superior; however, there was no significant differences in yield and crop parameters caused by the various fertilizers.

Minor element status: An unusual yellowing of the young leaves of banana was not due to deficiencies of zinc, boron, molybdenum, iron and manganese.

In other work (ul Haque, 1971; Messing 1969 and WINBAN 1970) it was found that sulphur deficiency was the most likely cause of the symptom which was corrected by the application of magnesium sulphate as part of the fertilizer blend. This potential problem needs to be continually monitored since boron deficiency was previously reported in the Montreal area where the rainfall is >2500 mm per annum and the climate continuously wet.

Re-calibration of fertilizer use and crop yields: An attempt was made to find whether the relationship between fertilizer use and crop yields which was established in the early work of Twyford and Walmsley (1973), (1974), (1974) could be improved for higher efficiency. This work was not well advanced by the time the Research and Development Division of WINBAN was discontinued. The fertilizer rates tested (16:8:24 NPK) were 1, 3, 5 and 7 lb/mat (0.4, 1.36, 2.02 and 2.83 kg/mat). The results showed a differential response between the plant and ratoon crops. The fertilizer rates did not affect any bunch characteristics in the first crop; however, in the second, the five and seven pounds per mat produced greater bunch weights while 3 pounds (1.36 kg) per mat resulted in more hands and fingers, indicating smaller fruit sizes. This work appeared to have ceased in 1992 i.e. over 12 years ago. This and earlier research indicated that the fertilizer requirements of the plant crop was different to that of the ratoon crop, the plant crop responding to fertilizers, presumable to build up nutrient reserves in the developing mat.

Twyford and Walmsey (1974) concluded that over a three year period from a plant crop, by differential fertilizer applications based on responses for each year, the cost of fertilizer could remain the same compared to a fixed rate of application (3 pounds/mat/year) and the overall yields could be much superior.

The nutrient balance between input and uptake based on the recommended fertilizer application rate of 3 pounds/mat/year of 16:8:24:4 as follows: Nutrients Amount added Amount *Excess (a) removed in (b - a) (kg/ha) bunches (b) N 326 56 270 P2O5 163 24 139 K2O 490 221 269 CaO not known 9 not known MgO 82 21 61 *based on hypothetically possible yield of 50t/ha (a) fruit plus two thirds of the external fruit stalk

30

In practice much less than 50t/ha yield is obtained and probably half of this would be a good expectation. Further, presently only the fruit is removed from the field and the whole of the external fruit stalk is also left in the field with the other plant remains. This means that the differential between input and uptake shown above would be in reality much greater. Therefore, the bulk of the fertilizer applied cannot be accounted for. Clearly, leaching losses through soil erosion and immobilization in soil are all important. Nevertheless soil analysis done as part of this study (Part II) showed a considerable build up of nutrients in any soil on which banana in particular was grown for some time. This is even the case on soils in which food and vegetable crops were also cultivated.

Points to consider in developing a soil management package for banana production in the future: (a) The fertility levels of the traditional banana producing soils have been built up to very good levels due to sustained high levels of fertilizer use. (b) With the fertility levels of the soils as they are, the normal recommendation for fertilizer use is too high; differential application rates from one year to the next and from plant crop to ratoons should be developed. (c) The application of magnesium should be more controlled; at present, the available magnesium levels in the banana soils is so high that there can be antagonistic effects in potassium uptake and metabolism; magnesium containing fertilizers can be rotated with non-magnesium containing ones. (d) There is strong indication that the banana growing soils are deficient in sulphur. This problem should be more defined through research and appropriate control measures introduced. (e) It is now more important that soil conservation measures be followed; any loss of top soil would mean that nutrient reserves are being lost and the ability of the soil to retain added nutrients is reduced. (f) A comprehensive programme of soil testing should be introduced and used as an aid in managing the fertility status of the soils.

Ihsan-ul-Haque 1971. The status of sulphur in West Indian soils. Ph.D. Thesis, Department of Soil Science. The Library, University of the West Indies, St. Augustine, Trinidad. (See Attachment 28) Eight West Indian soils were included in this study some being from Trinidad and some from St. Vincent (Montreal sandy loam, Akers sandy clay loam, Bellevue sandy loam and Soufrière cindery, gravelly, loamy sand). The total sulphur varied from 110 to 510 ppm which was considered rather low; over 95 percent of the sulphur was in organic form. There was a close relationship between organic carbon, total nitrogen and total sulphur and correlations were highly significant, indicating that most of the sulphur was in the organic form.

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Incubation studies were carried out to investigate the release of sulphur and nitrogen; sulphur and nitrogen release or fixed were estimated from 10 to 60 days incubation period. All the soils released sulphate when incubated at 300C and a rapid initial flush in mineralization of both nitrogen and sulphur occurred in the Montreal soil but an inconsistent pattern of release was obtained for the other St. Vincent soils. High correlation coefficients between organic matter and nitrogen mineralisation as compared with sulphur mineralized do not support the hypothesis that nitrogen and sulphur mineralized at the same rate.

Sulphate applied in the soil surface moved to variable depths suggesting that downward movements of sulphate increased with increasing amounts of water applied. Most of the sulphur applied to the Montreal soil was retained in the surface layer, probably due to the high organic matter content.

In studies of sulphate absorption by the soils from solutions supplying from 25 to 200 ppm of sulphate - sulphur, concentration dependent absorption was indicated for the soils. The data suggested that other mechanisms in addition to anion exchange, probably related to soil organic matter, may be involved in sulphate retention in these soils. In desorption studies, the amount of sulphate released decreased with each successive extraction. As much as 49 percent of the initially absorbed sulphate could be extracted in the first extraction from the Montreal soil which indicated weak retention capacity.

In greenhouse studies on the response of pak-choi (Brassica chinensis) to added sulphur, there was positive response for all the soils. Sulphur deficient plants were stunted and erect in appearance and the upper leaves had an abnormal yellowish green colour. Dry matter yields were highly correlated with sulphur content for the first crop but results were not significant for the second crop.

These results suggest that benefits may be obtained by the inclusion of sulphur in the fertilizer use programme in these soils.

See also: Haque, I. and Walmsley, D. 1973. Carbon, nitrogen and sulphur in some West Indian soils. Ghana Int. Jour. Agric. Sci. 6: 173-175. (Attachment 28a) Haque, I. and Walmsley, D. 1973. Adsorption and de-sorption of sulphate in some soils of the West Indies. Geoderma 9: 269-278. (Attachment 28b) Messing, J.H.L. 1969. Indications of sulphur deficiency in Windward Islands’ soils. Proceedings of a Soils Seminar held at UWI, Cave Hill, Barbados 29 – 30 May, 1969. 1 – 8. (Attachment 25)

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Cornforth, I.S. and Walmsley, D. 1971. Methods of measuring available nutrients in West Indian soils I. Nitrogen. Plant and Soil 35: 389 - 399. (See Attachment 29) Walmsley, D. and Cornforth, I.S. 1973. Methods of measuring available nutrients in West Indian soils II. Phosphorus. Plant and Soil 39: 91 - 101. (See Attachment 35) Ahmad, N., Cornforth, I.S. and Walmsley, D. 1973. Methods of measuring available nutrients in West Indian soils III. Potassium. Plant and Soil 39: 635 647. (See Attachment 36) Part 1: Methods of measuring available nitrogen were compared using response and uptake data from maize grown on 155 West Indian soils including soils from St. Vincent. Total soil nitrogen gave best estimates of available nitrogen when all soils were considered together. Correlations between test data and nitrogen uptake were best for acid soils, for soils with high cation exchange capacities and for soils with between 80 and 99 percent cation saturation. Differences between correlations for soils from different islands could usually be related to these soil properties.

Part II: Phosphorus: Nine methods of measuring available soil phosphorus were compared using dry matter yield response and phosphorus uptake data on the same soils as for the determination of available nitrogen reported in Part I above. Olsenâ&#x20AC;&#x2122;s method (using 0.5N sodium bicarbonate as extractant) gave the best estimates of available phosphorus and was also least sensitive to changes in soil properties such as texture, pH, cation exchange capacity and percent cation saturation.

Part III: Total and exchangeable potassium and potassium extracted with dilute acetic and suplhuric acids and boiling nitric acid were compared with dry matter yield response and potassium uptake by maize; the soils used were the same as those from Parts I and II of this study and included soils from St. Vincent.

Correlation coefficients for soil test values with percentage yield and potassium uptake were calculated using data from all the soils together and also when the soils were grouped according to pH (5.5, 5.5 - 7.0 and >7.0), percent cation saturation (<60, 60 - 79, 80 - 99 and 100 percent), cation exchange capacity (<10, 10 - 30 and > 30 cmol/kg soil) and texture (clays, clay loams, loams and sands). In general, correlations of soil test value with potassium uptake were superior to those with percentage yield. Total potassium gave no significant 33

correlations in any of the comparisons. The exchangeable potassium and potassium extracted by dilute sulphuric acid were the most successful methods overall and the least sensitive to changes in soil properties. The dilute acetic acid method was the least effective. This method was in use in routine soil analysis at the Imperial College of Tropical Agriculture, Trinidad, for many years.

(See also Walmsley, Cornforth and Ahmad, 1969).

The research reported in Parts I, II and III of this study which was essentially the same as that reported by Walmsley, Cornforth and Ahmad, 1969, Attachment 26, was well planned and carried out. In adopting the findings, however, it must be appreciated that soils from the entire Commonwealth Caribbean were included from different pedologic background and agricultural history. Some of the conclusions may therefore not apply to the St. Vincent soils which are all developed on volcanic materials. Regrettably, also, there are no competent analytical laboratories in the region presently at which farmers can get their soil samples analysed at a reasonable cost. If such laboratories are re-established in the future, the results reported above could be used in the initial stages of establishing a soil testing service.

Walmsley, D., Twyford, I.T. and Cornforth, I.S. 1971. An evalution of soil analysis method for nitrogen, phosphorus and potassium, using banana. Trop.

Agric. (Trinidad) 48: 141 - 155. (See Attachment 30) This study was part of a programme to assess soil fertility in the Windward Islands using a series of single replicate factorial nitrogen, phosphorus and potassium fertilizer experiments; Robusta banana was the indicator crop. The aim was to find the analytical methods which most accurately predicted yield response so that these can be used for routine analysis of banana growersâ&#x20AC;&#x2122; soil samples of an advisory service on fertilizer requirements. Twenty-eight sites were used from Grenada, St. Vincent, Dominica and St. Lucia of which nine were from St. Vincent. Seven of the sites consisting of low level yellow earths and two from recent volcanic ash.

Seven methods were used to estimate available nitrogen, ten for available phosphorus and six for potassium. The methods were selected on their ability to predict crop response to fertilizer additions by grouping the soils into adequate and deficient classes.

The anaerobic incubation method was best for nitrogen but was only able to predict responses correctly 66 times out of 100. Predictions from cation saturation were better than any of the nitrogen tests tried. A critical value of 90 percent cation saturation gave 78 percent correct predictions of response.

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A modified Bondorff method was recommended for soil phosphorus. This method and the Olsens’ bicarbonate extract gave 94 percent correct predictions of crop response to superphosphate. The critical test value was 40 parts per million extractable phosphorus by Bondorff’s method and 2.5 parts per million by Olsen’s.

Exchangeable potassium was recommended for routine soil analysis. Morgan’s acetate extract and Pratt’s sulphuric acid method gave equally good (81 percent correct) estimate of crop response to potash fertilizer. The critical value for available potassium was 0.40 cmol/kg soil.

The recommended methods were suggested for use in routine analysis of farmer’s samples as part of an advisory service to banana growers in the Windward Islands. It is not known to what extent WINBAN Research utilized these methods in its advisory work. However, with that service no longer in operation, there is really no system in place to provide national fertilizer use recommendations for farmers. Much time has elapsed and the fertility levels of the soils would have changed. Therefore much of this work should be repeated and intensified in St. Vincent to facilitate a good fertilizer use advisory service.

See also Walmsley, D., Cornforth, I.S. and Ahmad, N. 1969. Methods for estimating available nutrients in Windward Islands soils. Department of Soil Science, University of the West Indies, St. Augustine, Trinidad. Report No. 15.

Baynes, R.A. 1972. Guidelines for better peanut production in St. Vincent, W.I. Bull. No. 2, Regional Field Experimental Programme, Department of Soil Science, The Regional Research Centre, The University of the West Indies, St. Augustine, Trinidad. (See Attachment 31) In this publication, all relevant verified information on the production of peanut in St. Vincent was put together including details on land preparation, seed selection and treatment, planting techniques, fertilizer use, weed control, pest control and harvesting. A complete package on fertilizer use was presented.

This is a good guide for any producer of peanut and for extension workers who are involved.

Hatten, C. 1972. St. Vincent II. Geomorphology and soils studies, the Yamba river basin including high level yellow earth (Montreal and Greggs) and low level yellow earth (Akers series). (See Attachment 32) This is a highly detailed study of the pedological inter-relationship among these soils which included soils developed in continuously wet (>2500 mm annual rainfall) to situation in which there was a marked dry season (1725 to 1875mm

35

annual rainfall). Fifty-two soil profiles were studied in detail located in all aspects of the landscape of the study area.

The following conclusions can be made: Pedogenesis was shown largely to be influenced by stability or movements of the soil-forming materials, and the content and movement of water within the soil profile.

The high-level materials showed very high permeabilities and water holding capacities and movement of water occurred down to the ground water table overlying less weathered consolidated material of much greater age. Well developed flat terrace surfaces were common and high rainfall led to much leaching of bases and probably silica, resulting in clays with very low cation exchange capacities and low saturation with bases but very high anion-fixing capacities. The organic matter contents of the A-horizons were extremely high (up to 12% carbon) but this did not affect appreciably the measured cation exchange capacity. The material represents a very real problem for fertilization, and further work appears necessary on levels, placement and timing of applications in order that the potential productivity as determined by the favourable climatic and soil physical characteristics might be realized. While surface wash and creep were minimized by the both structural properties and the even climatic factor, mass movements were notable near to water coarses.

Properties of the soils of the slopes were similar to those of the stable sites, although further textural irregularities were observed due to wash following exposure by slumping, and also some reduction occurred in finer textured horizons.

Where consolidated rock was close to the surface on the slopes of the main ridges, the levels of cation exchange capacity and cations increased particularly for the lower horizons developing in weathering rock, and the ratio of magnesium and sodium to cation exchange capacity likewise increased. The same relationship applied to some lower horizons of this material on slope positions overlayed by horizons of permeable ash material showing Montreal Series characteristics. In areas of colluvial and alluvial accumulation, this tendency was also observed particularly where drainage was poor. Areas of poor drainage associated with the greater impermeability of the weathered consolidated materials furthermore promoted mass movements; while well drained sites appeared stabilized. Land surfaces and slope formations could be largely interpreted by continued action of these processes.

The low-level materials showed contrasting physical properties, particularly a hardening of sub-surface horizons by secondary ferric oxides and reduction of permeability of finer-textured sub-surface horizons on slope positions. The latter

36

promoted formation of slope-orientation structures together with indications of creep-induced shearing. Iron cementing appeared to be a function of seasonal drying and was more pronounced when the B-horizon was more exposed due to surface wash removals of A material. Surface wash was more important here due to former intensive use of the land, poor surface soil structures, and high intensity, short-duration rainfall. Where original ash deposition involved finer textured material being deposited only on the flat interfluves and lower-gradient slopes, subsequent soil structure formation stabilized the finer-textures such that the coarser fractions of sand and silt were selectively removed by wash on the slope positions. Hence surface textures of slopes were more clayey on slope than on flatter positions. Surface wash accumulations have buried former Ahorizons in which much organic matter and P has remained although cation exchange capacity and the divalent cations are lower than for the underlying Chorizon material. Levels of cation exchange capacity, cations and phosphorus were much higher for the low-level than for the high level soils, a function of leaching and clay mineralogy. Surprisingly phosphorus levels were often highest in sub-surface horizons, possibly a reflection of more intensive former use of the land. Potassium-levels were occasionally very high due to application of the high-potassium banana fertilizer. Sodium levels were much higher in the lowest horizons, below the zone of common rooting, particularly for the lower elevations; this being also observed in finer-textured horizons on slope positions.

In depressed positions with a high water table, levels of sodium and particularly magnesium were very high, while montmorillonite genesis had occurred giving well structured cracked surface horizon and gleyed sub-surface horizons.

Hatten, C. 1972. St. Vincent III: Geomorphology and soils studies of the Brighton area having prolonged dry season. Department of Soil Science, The University of the West Indies, St. Augustine, Trinidad, W.I. (See Attachment 33) This study was similar in scope and objectives to St. Vincent II. The following are the conclusions.

Recent accumulations of wind-blown coastal sand containing the same plagioclase, pyroxene, amphibole and olivine minerals in apparently similar proportions to those of the ashes and lavas showed minimal differentiation in pH of the soil horizons, and also showed accumulation of secondary limonite in the surface horizons which appeared more clearly orange-yellow in colour on drying.

Significant cementation was also observed with these superficial horizons after drying, probably also due to the limonite, and this likewise applied to undulating, partly continual bands within the C-horizon. The limonite-cemented horizons were interpreted to play an important role in stabilizing the sand surface (together with vegetation) and were a product of superficial pedological weathering (involving decomposing organic residues, rapid changes in water 37

availability, soil solution concentration and temperature), rather than geological weathering involving hydration and hydrolysis under more uniform conditions.

Surface wash gave colluvial deposits in depressions within the dune areas in spite of apparent high permeability of the materials. The role of man was interpreted to be critical here in removing the plant cover and exposing the soil surface. Very high intensity rainstorms would have interacted with these features of misuse in further breaking of the weak surface structures and blocking of pores, establishing lateral surface movements on continuing rainfall.

Pottery of the four Indian Periods 400-2000 BP were found associated with colluvial deposits in these positions. These former deposits had remarkably constant colour (10YR2/1), pH 6.9 and maximum textures, and high permeabilities, which could be explained by weathering and organic matter complex staining under uniform physical conditions for the significant time period involved.

In the lowest depressions greater textural variation was observed, deposition having occurred over at least two cycles of back-swamp alluviation with subsequent pedogenesis involving high water tables. In some areas these horizons were under-layed by coarse beach sand and overlayed by currentlyaccumulating sand: in some other areas coarser alluvial deposits under-layed these horizons. A fall in sea-level resulted in down-cutting of the lower portions of the small rivers, the banks being steep (>45Ë&#x161;) and 2.4 to 7.5 m high. While contemporary alluviation would not include flooding of these rivers, low permeabilities of the former alluvial back-swamp materials would have caused perched water tables to rise above the surface. Superficial horizons of montmorillonitic clays have been formed in these areas, accompanied by hogwallowed micro-relief. Underlying horizons usually showed mottling associated with fluctuating water tables: ferric oxide streaks tended to correspond to channel linings (sometimes as pipes) and to vertical macro and micro-structural cracks, often associated with a pronounced vertically-oriented flake microstructure, (deep alluvial sand deposits) or rounded blocky structures (former waterlogged B-horizons of mainly sandy textures but underlying and incorporating some of the illuviated finer-textured A-horizon material). Under waterlogged or even moist conditions all sand grains appeared weathered to the extent that they were crushable between the fingernails. While many weathered products of the minerals appeared retained in situ, preserving the original shape of the grains and non existing elsewhere as silt or clay particles, iron appeared the exception and contributed significantly to the surface colours of the particles and to their degree of cementation and form of larger structural units.

Ash covered land surfaces (probably late Pleistocene, i.e. 10,000 - 20,000 years BP.) showed a comparable situation to that of the coastal sand. Five major pedo-geomorphic processes could be recognized. Again surface wash of the A-

38

horizon materials had been extremely important and the characteristic uniformly dark buried A appeared very commonly. Surprisingly it appeared over creep slopes and very shallowly-depressed interfluve positions, as well as in the more obvious concave colluvial areas. This would support the hypotheses that: i. Removals of the vegetation promoted surface wash movements: even steeper areas possessing protective vegetation would have retained their surface horizons; ii. protective vegetation could lead to surface accumulations of washed material and additions of ash.

Some valley bottom sites did not show this buried A-horizon, and contemporary A horizon were relatively superficial: such sites would be zones of overall surface removals, possibly due to the greater volume of influxed water, rises of watertable, and relatively greater use of such sites for cultivation. A-horizon depths therefore do not show a simple relationship with slope form and gradient rather, the presence and form of vegetation appeared to be equally important.

Eluviation appeared of lesser importance than the other processes, and included physical wash and physico-chemical elluviation. The latter process appeared less well defined and included translocation of organic complexes and redeposition as irregular, slightly darker streaks, and also the movement and redeposition of iron complexes which in several sites appeared independent of reduction processes.

Physical wash showed indications of inter-horizon and local movements, and appeared clearer on the interfluve sites, but was of much lesser importance than expected from considerations of pore geometry. Very high permeability of the structures and high stability of the finer particles within these structures would explain this.

Iron cementation of B-horizons occurred to the extent of forming massive structures of extremely hard consistency, these however appearing permeable and usually very dry. Those horizons would represent maximum resistance to creep and mass movements and are generally found on the interfluve positions possessing convexity - hence the overlying A-horizons are more shallow than usual due to surface wash removals, while drying experienced in the A-B transition would further encourage hardening. In the relationship of these horizons to those of the creep slopes, the irreversibility of the ferric oxide hardening and the continued permeability of the structures would appear to be critical. Observations indicate the horizontal to slope-oriented structural faces become increasingly obvious with depth from the A-B transition, and while hardened structural units exist at those levels, it was clear that the faces represented orientation of the finer particles (some degree of stress cutan formation), and reduction processes probably associated with lateral water

39

movements. Hence an overall directional lateral component of water movement appeared to limit the apparent great stability of the ferric oxide cement B. The slope-oriented, clay surfaced structural faces are characteristic of a creep slope. Impeded vertical drainage, lateral water movements and locally confined reduction, accelerated weathering and creep-induced shearing and confined within finer-textured bands occur and appear to be interacting attributes of the system. A positive change in one of the attributes is liable to promote similar changes in the other attributes, but constraints on the system comprise rooting, resistance of structures to shrinkage, swelling and reduction, and the decrease of stress gradients with decrease in slope gradient. Quantitative data on the attributes of the system are required to obtain the relationship of one attribute to others for individual pedons, and hence relationships applying to the entire system. From observations elsewhere it appears that much variation exists in the degree of creep movements (or their characteristic features). Further, the relationship of creep to other movement processes (notably earthflow and slumping) needs to be determined, involving hydrological cycles for such slopes.

Waterlogging occurred in flat accumulational sites and on slopes and interfluve sites, and included both ground and locally perched water tables. Its significance for determining plant communities and land utilization was very great, particularly as the areas had the most pronounced dry season of the Island.

Pedologically, reduction was its most important effect, and iron oxides the most important substrates.

Reduced, ferrous forms of iron were more readily dissolved and translocated in the ground water, and were redeposited and re-oxidised when the water tables fell. The effect of the process was to re-enforce structure stability, particularly in cases where the horizon was subjected to appreciable drying. Waterlogging also appeared to increase the friable nature of the individual sand minerals; this could be attributable to increased weathering or removals of secondary cementing agents (eg. ferric oxides) from partly weathered grains, or simple physical effect of water layers being present within the micro-cracks, reducing attractive forces between the faces. The presence of swelling clays and hog-wallow micro-relief in seasonally-waterlogged positions suggested rapid pedogenesis of such clays under these conditions. This must also be interpreted in the light that these positions have shown back-swamp alluvial accumulations involving very fine material. Again comparative quantitative data needs to be obtained on the mineralogy of such as materials.

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Baynes, R.A. and Walmsley, D. 1973. Fertility evaluation of some soils in the Eastern Caribbean. Department of Soil Science, University of the West Indies, St. Augustine, Trinidad. Report No. 17. 80p (See Attachment 34) The soil fertility status and response to fertilizer of Akers sandy clay loam, Bellevue sandy loam and Soufrière cindery gravelly loamy sand were assessed through soil analysis and field experiments using maize as the test crop during 1966, 1967 and 1968. This was done in conjunction with other West Indian soils.

For soil testing, the results confirmed that the methods of soil analysis that were in use at the Central Analytical Laboratory on UWI Campus were quite good for measuring available soil nitrogen and potassium but that the method for determining available phosphorus, should be changed from Truogs’s to Olsen’s method. Critical values to indicate levels of adequacy of nutrients in the soils were proposed. (See also Walmsley et al. 1969, 1971).

In field experiments, good responses to nitrogen fertilizers were obtained on the three soils, that on the Soufrière soil being particularly high. Addition of phosphate and potash fertilizers resulted in increased yields at the lowest rates used but at higher rates no further increases were obtained except for the Soufrière soil.

The recommended fertilizer additions for the three soils for maize production were as follows: nitrogen:

50 kg/ha for the Akers and Bellevue soils (=110 kg/ha of urea or 225 kg/ha of sulphate of ammonia 150 kg/ha for the Soufrière soil phosphorus: 25 kg/ha for all soils (= approximately 125 kg/ha of triple superphosphate) potassium: 50 kg/ha for all soils (= approximately 100kg/ha muriate of potash)

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Twyford, I.T and Walmsley, D. 1973; 1974. The mineral composition of the Robusta banana plant I. II. III. IV.

Methods and plant growth studies. Plant and Soil 39 (1973): 227 243. (See Attachment 37) The concentration of mineral constituents. Plant and Soil 41 (1974): 459-470. (See Attachment 38) Uptake and distribution of mineral constituents. Plant and Soil 41 (1974): 471 - 491. (See Attachment 39) The application of fertilizers for high yields. Plant and Soil 41 (1974): 493-508 (See Attachment 40)

Part I: In this study which included one site in St. Vincent but others in St. Lucia and Grenada, the problem of the nutrition of the banana plant and the limitations of traditional field fertilizer trials were described, dry matter production at different growth stages were presented and differences in pattern were related to site factors. This would make it difficult to extrapolate experimental results from one territory to the other. Distribution and re-distribution of dry matter amongst the various plant organs were given for the different stages of growth. Calculations of fresh and dry matter for a field production of 25 and 50 tonnes per ha of banana were made.

Part II: Part II of this study was carried out at the same sites as for Part I. The concentrations of nitrogen, phosphorus, potassium, calcium and magnesium in the different parts of the Robusta banana plant at various stages in the growth cycle were presented. The plants were sampled at sites with obviously differing soil properties and on which the fertilizer practice varied; nevertheless, the pattern of nutrient concentrations was similar at all sites. The effect of the variability within sites of organ concentrations similar on the choice of a diagnostic tissue was discussed. The changes of nutrient concentrations in the organs which take place during the life cycle are described in relation to physiological function .

Concentrations in the centre portions of the fourth leaf lamina sampled at the large plant stage were less variable than in any other plant part for all nutrient elements.

This confirms its value as a diagnostic tissue.

The rapidly differentiating tissue in the banana throughout its life cycle were associated with and depended on high concentrations of particular nutrients but these nutrients were not always the same ones. Potassium was outstanding in being abundantly involved in all of them, especially fruiting organs. Phosphorus and nitrogen

42

seemed to be of great importance in most tissues but not so much those involved in fruit development.

Calcium and magnesium appeared at high levels only in organs in the vegetative phase, especially meristem.

Relatively high concentrations of these two elements were found also at all stages of growth in support, transport and storage organs, increasingly so as the plant ages. The importance of a high nitrogen content in leaves throughout the life of plant was also clear.

Part III: In Part III of this study, mineral composition of the Robusta banana plant at different stages of growth was used to compute fertilizer requirements for high yields (50 t/ha) on soils of low basic fertility. Emphasis was laid on the difference in fertilizer requirement between the first and subsequent years. A fertilizer composition of 9:9:35 was found suitable for all stages of the banana crop but the amount required decreased from the first year to each subsequent year by 87 percent. Thus, it was found that on a relatively poor soil if the yield expectation were 50t/ha, 6.5 t/ha of 9:9:35 or 2.5kg per stool with a plant density of 2,500/ha should be applied. For ratoon crops 0.65t/ha or 0.25kg/stool was needed to maintain yields.

Over a period of three years or more this method of fertilizing would not require more fertilizer than is normally given. Therefore only a re-arrangement of the fertilizer costs with time was involved. In the first year, weather permitting, fertilizer can be given in six evenly spaced doses. About half of the total dose should be given in the fourth and fifth applications. After the first year equal applications can be made three or four times per year.

On soils which do not supply sufficient calcium and magnesium, the amount of fertilizer to supply the plants needs would be about 250 kg calcium and/or magnesium oxide as needed, reducing to 10 to 20 kg/ha / year thereafter.

High yields were equally dependent on adequate fertilizer use as well as on good agronomic practices. The results reported in Parts I, II and III of this study were essential on which to develop a fertilizer use strategy for the banana crop. With these foundation studies, there is adequate basis for rational fertilizer use for high yields. Some of this work needs to be done more intensively in St. Vincent for verification since experimental sites existed in Grenada and St. Lucia in addition to St. Vincent. There is enough differences in properties of the soils of these islands for this to be justified.

Part IV The fertilizer rates for the production of up to 50 tonnes/ha per year of fruit were proposed as well as strategy to use the fertilizer from the plant crop to the

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ratoons. For the first year 6.25 tonnes/ha of a 9:9:35 NPK blend (2.5 kg/mat) were needed but this should be reduced to 0.65 tonnes/ha/yr (0.25 kg/mat) for the ratoon crop. Over a period of three years, the same amount of fertilizers would be sued as per the current recommendations but higher yields would be obtained. Even with the recommended six split applications during the first year, it is doubtful whether the soils would be able to retain the nutrients added. At any rate such recommendations should be verified before introducing them to farmers.

See also WINBAN, 1970-1992, this issue.

Baynes, R.A. and Walmsley, D. 1974. Mineral nutrition of the St. Vincent groundnut (Arachis hypogaea L). Trop. Agric. (Trinidad) 51: 27 â&#x20AC;&#x201C; 35. (See Attachment 41) An experiment was conducted at Union Estate on Bellevue sandy loam which is an important groundnut producing soil, to assess whether the crop responded to addition of nitrogen, phosphorus, potassium, calcium, magnesium and sulphur.

The yield which was about 2 tonnes/ha of air-dried nuts in shell was not improved by additions to the soil of the nutrients. The percentage of empty pods was reduced by the use of ground limestone at sowing while triple superphosphate (45 kg phosphate per acre) increased the shelling percentage.

The mean dry matter production was about 6t/ha of which kernels comprised 22 percent compared with 50 percent reported elsewhere for other varieties.

Plant uptake of nutrients applied was determined at two-weekly intervals up to harvest at 105 days after sowing. The data showed that the levels of the nutrients in the plant were adequate to produce maximum yield of the variety.

Lack of response to the fertilizer was attributable to an adequate supply of nutrients from the soil.

It was estimated that to maintain soil fertility under this crop in St. Vincent, the minimum fertilizer application required, taking into account symbiotic nitrogen supply and phosphate fixation would be about 100kg/ha each of ammonium sulphate and single superphosphate and 50 kg/ha of muriate of potash. These fertilizers would also supply sufficient calcium, magnesium and sulphur.

Macfarlane, M. 1974. Phosphate studies on volcanic ash soils from St. Vincent.

Ph.D. Thesis, Department of Soil Science, The Library, University of the West Indies, St. Augustine, Trinidad. (See Attachment 42) This project considered the phosphate status of four surface and two sub-soils derived from volcanic ash of different ages under varying climates in St. Vincent.

The soils were Montreal (A and C horizons), Soufrière (A horizon and buried 44

horizon), Akers, Bellevue and Greggs - all A horizons. Clay mineral analysis was also done and the results were used to show relationships with phosphate fixation and release.

Phosphate fractions of the soils In general total and inorganic phosphate contents of the soils were high.

Available phosphate as determined by the methods of Olsen and Bondorff, was except for the Bondorff phosphate value for Montreal C, higher than the critical level determined by Walmsley et al. (1969; 1971; 1973; 1974), and thus plants would be expected to show no response to applied phosphate fertilizer.

However optimum phosphate values, i.e. phosphate additions required to maintain a concentration of 0.2 ppm in the soil solution determined from phosphate sorption, showed positive phosphate requirements for most soils.

Phosphorus requirements ranged from 0 to 1250 parts per million to maintain optimum values. Montreal and Greggs soils showed much higher phosphate requirements than the Bellevue, Akers and Soufrière soils. Correlation between ‘Optimum P’ and Olsen phosphate gave r = 0.542* and there were no relationships between ‘Optimum P’ and other forms of phosphate since none of the correlations reached significance. Thus if ‘Optimum P’ is a reasonable measure of phosphorus status, then the Bondorff and Olsen methods do not extract phosphorus from these soils that is truly ‘available’ for plant growth.

It was found that P sorbed by the Montreal soils was mostly tightly bound, that for Bellevue and Akers less so and that for the Soufrière soils least tightly bound.

Similar binding energy constants were thought to imply similar sorption mechanisms and binding sites.

‘Optimum P’ was highly correlated with extractable aluminium (extracted with 1M ammonium acetate at pH 4.8), r = 0.93*** and since the relationship is linear it was suggested that extractable aluminium might be used as a suitable measure of ‘Optimum P’ since the method is simple and rapid.

Phosphate sorption determined in the presence of sodium or potassium showed lower phosphate requirements than those from calcium solutions. Adsorption of phosphate in the presence of calcium for Montreal C was different from those in the presence of potassium or sodium which is believed to be due to precipitation of calcium phosphate in the calcium solution.

Sorption curves determined on oven dried soils showed much increased ‘Optimum P’ values for the Montreal and Soufrière soils, those for Akers and Bellevue were not much affected. It was suggested that the increased ‘Optimum P’ values were due to drying of alumino-silicate gels (allophane) giving smaller particles with higher surface area and greater number of exposed aluminium sorption sites.

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Phosphate sorption Sorption of phosphate by the Montreal soils was affected by removal of organic matter or extractable aluminium. Removal of aluminium and iron by appropriate chemical methods significantly reduced phosphate sorption between 7.2 and 78 percent. Regression analysis showed that variation in percent aluminium oxide accounted for 82 percent of the variations in phosphate. Inclusion of percent iron oxide in the analysis did not improve r2 significantly. It was thus concluded that aluminium extracted by the various reagents was the major reason for the reduction in phosphate sorption.

Amelioration studies Few of the ameliorants used in an attempt to reduce phosphate sorption by the Montreal soils were effective. Silica was effective in both sodium acetate and calcium chloride media. Sodium silicate was found to be effective in sodium acetate and starch in calcium chloride. Glucose in calcium chloride was found to reduce phosphate sorption for Montreal A and sucrose in the same medium for Montreal C. The effects of silica, starch and glucose were thought worthy of further attention.

Investigation of sorption of phosphate in the presence of high concentrations of silica, glucose and starch led to the conclusion that silica and glucose at 20 percent and starch at five percent were most effective at preventing phosphate sorption.

Several ameliorants increased ‘available’ Bondorff and Olsen phosphate. Silica increased ‘available phosphate’ in most experiments. Glucose and starch among others also increased ‘available phosphate’ in some. Results were not always consistent between the soils. The 20 percent silica and five percent starch treatments gave the highest ‘available phosphate’.

Increasing glucose concentration decreased ‘available phosphate’ measured by these methods.

In a five week incubation study silica was shown to decrease phosphate sorbed for Montreal C. ‘Available P’ methods confirmed this up to three weeks. For Montreal A, increased available phosphate was predicted by all methods (sorption and extraction) initially, but only by the Olsen method at later stages.

Starch gave increased available phosphate at five weeks but was not beneficial at earlier stages. The same was observed for glucose.

Greenhouse experiments A preliminary pot-test showed significant positive response of tomato to applied phosphate for all soils, showing P deficiency in all soils and confirming predictions from P sorption studies. Phosphate deficiency appeared to be more

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severe in the Montreal than the other soils, which was also predicted by the sorption curves.

The tomato plants showed no positive or negative response to magnesium, manganese or boron except on Montreal C which appeared deficient in boron.

In a pot-test investigating response to phosphate applied up to twice ‘Optimum P’ as determined from isotherms, the Montreal soils, Soufrière A and Akers gave maximum yield at ‘Optimim P’; only in the Montreal soils were these significantly different from yields at all lower levels of applied P. Bellevue and the buried Soufrière soil did not give maximum yield at ‘Optimum P’ but in neither case was the yield at ‘Optimum P’ significantly different from the maximum. The maximum yield of Montreal C was significantly less than the other soils, indicating problems other than phosphate deficiency were present. Phosphate uptake increased linearly up to 800 parts per million for Montreal, and up to 150 parts per million for the other soils. Nitrogen and potassium uptake were also markedly increased by applied phosphate.

Response of tomato to residual phosphate after the first harvest was much less than expected from the high phosphate applied initially, indicating the limited capacity of the soils to maintain available phosphate levels even when very high rates of phosphorus were applied.

Applied phosphate reduced extractable aluminium levels considerably in the Montreal soils. The relationship was linear for these two soils and maximum yields were obtained only where extractable aluminium had been reduced to the same level in both soils. Extractable aluminium was less than this ‘critical level’ for all treatments of the other soils. Lack of growth at zero or low applied phosphate for the Montreal soils was thought in part to be due to this aluminium phosphate uptake by the plants. Extractable aluminium and ‘Optimum P’ determined after harvest were highly correlated r = 0.970***.

Phosphate sorption isotherms constructed after the first harvest confirmed that all soils had positive phosphate requirements, whatever the rate of phosphate applied, which accounted in part for the lack of growth of the second crop.

The relationship between phosphate applied and phosphate requirement after five weeks growth for tomato was linear. The higher the phosphate applied, the lower was the future phosphate requirement. The regression coefficients suggested that applied phosphate would be twice as effective at reducing subsequent requirement in the Soufrière soils as it was in the other soils. This is consistent with the low bonding energy constants obtained from the Langmuir plots.

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Growth of tomato plants in a pot-test studying the movement of applied phosphate into Chang and Jackson, Olsen, Bondorff and organic phosphorus fractions using 32P was not good except in the case of Soufrière A. Phosphate moved mainly into the aluminium-P fractions and less so into the iron-phosphate fraction. 32P results implied that the plants took phosphate from the Olsen extracted fraction late in the experiment.

There was more movement into the calcium-phosphate fraction for the Montreal soils than for Soufrière. Calcium phosphate in the C horizon was three to five times that for the A horizon. High applied P increased organic P for Montreal C as in previous experiments.

Physical, chemical and mineralogical analysis: The soils were dispersed by two methods. Zirconium nitrate solution dispersed all the soils used, a method using distilled water and an osterizer dispersed all the soils except Montreal C. The osterizer method appeared to give less clay than the zirconium nitrate method, which may have been due to incomplete dispersion by the former method. The Montreal A soil appeared dispersible by osterizer only when the organic matter was present, since the peroxidised soil was not dispersed by this method.

The silica sesquioxide analyses of the clay fractions reflected the relative weathering of the soils. The Montreal soils, occurring in areas of high rainfall, with short dry seasons, had lower silica:alumina and silica: aluminium oxide plus iron odixe ratios than Akers and Bellevue soils, whilst the Soufrière A horizon has high ratios reflecting its comparative youth.

Amorphous clay extracted by boiling sodium hydroxide solution was higher in A12O3 than SiO2 in all cases except Soufrière A; lower ratios were again shown by the more weathered clays. The increased amorphous material did not conform to the molar ratios of halloysite or kaolinite.

The total clay amorphous alumina and ignited alumina, when expressed as percent of the whole soil, were all found to be correlated with ‘Optimum P’, confirming previous results where reduction in phosphate sorption was found to be correlated with aluminium extracted from the soils by various reagents.

X-ray diffractograms showed primary minerals present in the clay fractions, notably plagioclase. Cristobalite appeared to be present in all samples; 2:1 minerals, probably montmorillonite and chlorite, were also present. There is some indication of halloysite or kaolinite in all samples except Soufrière A. Akers and Bellevue showed most prominent peaks which collapsed on ignition, confirming halloysite or kaolinite.

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Infra-red analysis confirmed hallosite in the Akers and Bellevue clays. The Montreal and Soufrière clays appeared to be dominated by allophane, allophane B in the A and buried A horizons, and allophane A in the Montreal C horizon.

There was some indication of halloysite in the clay residues of the Montreal and buried Soufrière soils; some of the peaks, however, in the ignited samples may be attributable to cristobalite. There were possible indications of imogolite in the Montreal A and Soufrière clays. Clay minerals in the Montreal and Soufrière soils appeared to be less ordered than in the Akers and Bellevue soils.

These results implied that the high phosphate sorption capacity of the Montreal soils was due to allophane of high aluminium content; although the Soufrière soils also contained allophane, it was of a less weathered more siliceous nature, which would reduce the phosphate sorbing power of the aluminium present.

Akers and Bellevue contained clay minerals of a more crystalline nature with less ability to sorb phosphate.

Sorption of phosphate by the clays confirmed that Akers and Bellevue sorbed less than the Montreal and Soufrière A clays. The buried Soufrière clay showed sorption of the order of Bellevue and Akers probably due to its less weathered nature compared with Montreal. Regression analysis of all the results except those for Soufrière A again showed aluminium oxide to be the major factor affecting phosphate sorption. The lack of agreement of the Soufrière A results could be due to the very small quantity of aluminium extracted from these clays.

Warkentin, B.P. and Maeda, R. 1974. Physical properties of allophane soils from the West Indies and Japan. Soil Sci. Soc. Amer. Proc. 38: 372 - 377. (See Attachment 43) The allophanic properties of several soils from Dominica, St. Vincent and Japan were compared. The St. Vincent soil used in the study i.e. Montreal had halloysite/kaolinite in addition to allophane which was estimated to be between 15 and 47 percent. Plasticity and shrinkage were measured as indicators of other physical properties. Several chemical measurements commonly used to characterize allophane were also made. Infra-red spectra and amount of rehydration were both related to the measured physical properties. The plasticity characteristics of allophane, high liquid limit, low plastic index and decrease of plasticity index on drying are suggested as a basis for rating the amount and nature of allophane in soils.

Based on the results of these studies, the Montreal soil exhibited weaker allophanic properties compared to the La Plaine and Boetica soils from Dominica.

This is ascribed to more maturity of the St. Vincent soil. Despite the problems in measurement, plasticity is likely a good criterion for characterizing allophane soils. It is an easy measurement to make and differentiate allophane soils from 49

other soils as well as differentiating within the allophane group. There is one difficulty in interpreting plasticity measurements in the laboratory since the values are influenced by the drying history in the field prior to sampling. This means that the difference in plasticity between field and over-dry water content cannot be used as a measure of allophane activity.

This work, although well conducted, is not very helpful in providing a practical identification and characterization of allophanic soils in the field, although it provides some of the theoretical reasons for the behaviour of these soils.

Identification of allophanic soils of St. Vincent is still largely dependent on the results of chemical soil analysis and some simple physical behaviour.

Macfarlane, M. and Walmsley, D. 1977. Effect of soil solution phosphorus in volcanic ash soils on the response of tomato (Lycopersicum esculentum) to added phosphates. Plant and Soil 47: 547-558. (See Attachment 44) Experiments were carried out to determine the amount of phosphate which had to be applied to high level yellow earth Montreal (A and C horizons), low level yellow earth (Akers and Bellevue) and volcanic ash (Soufrière A and C horizons) to maintain an “optimum” phosphorus level in the soil solution of 0.2 part per million which was found by others to be very adequate for plant growth. The Montreal soil required 800, Soufrière A 150, Soufrière C 200, Akers 100 and Bellevue 100 parts per million of added phosphorus to maintain a concentration of phosphorus in the soil solution of 0.2 part per million.

In pot experiments with these soils with tomato as the indicator plant, phosphorus was applied at the rates of 0 - 1600 parts per million for the Montreal soils, and 0 - 300 parts per million for the Soufrière, Akers and Bellevue soils. Uptake of phosphorus and dry matter yields were linear for the Montreal A and C soils up to 800 parts per million, for Soufrière A horizon and Akers up to 150 parts per million, Bellevue up to 200 parts per million and for Soufrière C horizon, up to 300 parts per million.

Dry matter yields of the second crop of tomato after further addition of nitrogen and potassium but no further phosphorus were very much lower (less than one third) than for the first crop. Further, no plants grew in the Montreal C horizon soil. In all cases yields were between one-sixth and one-third of those of the initial experiment. Clearly, the capacity of the soils for maintaining available phosphorus is limited as even where twice the “optimum” level was applied, the soils did not give satisfactory yields.

After the first harvest, the available phosphorus in the solution was much reduced from the “optimum” level of 0.2 part per million in the soil solution. In the case of the Montreal soils, high levels of available aluminium was a 50

contributory factor to lack of response to phosphorus. Among the soils studied, there was evidence that there were variations in the ability of the soils to immobilize the added phosphorus, the volcanic ash soils maintaining the highest rate of availability.

This study has important implications for the management of phosphate fertilizer application for St. Vincent soils against the background of high fixation capacities. Currently, many of the soils especially those which were used for the cultivation of banana showed a high level of availability of the nutrient but fertilization with this nutrient had to be maintained if crops were to be adequately supplied. The rates of fertilizer use should be moderated in response to results of soil tests, but fertilizer use should not cease. The practical implications of this work is so important that the results should be verified by more extensive studies. It also underlies the importance of soil conservation to prevent loss of top soil in which the added fertilizer phosphorous is concentrated.

(See also Macfarlane, 1974).

Ahmad, N. 1981. An investigation of soil conditions of farmersâ&#x20AC;&#x2122; holdings in St. Vincent. Consultant Report No. 8. The Caribbean Agricultural Research and Development Institute, The University of the West Indies Campus, St. Augustine, Trinidad, West Indies. (See Attachment 45) As part of the CARDI/USAID Small Farm Multiple Cropping Research Project in St. Vincent conducted in the early 1980s, 43 small farms were visited in five geographic areas as follows: Area 1 Area 2 Area 3 Area 4 Area 5

Georgetown/ Mt. Bentinck/ Dandrade 13 farms Peruvian Vale/ Richmond Park 9 farms Belmont/ Calder/ Stubbs 11 farms Belair/ Fountain 6 farms Troumaka/ Belmont/ Hermitage 4 farms

The farms were located on 15 of the most important agricultural soils; composite soil samples (0 - 15 cm depth) were taken from each of the farms and were analysed for pH, particle size, cation exchange capacity, exchangeable calcium, magnesium, potassium and sodium, total carbon and nitrogen, C/N ratio and available phosphorus. On the basis of these properties and other observations 51

made in the field, recommendations were made for appropriate soil management which were soil and site specific. Observations were also made on the status of soil erosion on each farm. In general, the recommendations were biased to the needs and goals of the project.

Apart from the soil analysis reported in Part II of this study, this is the only other example of soil analysis having been done on many of the soils of St. Vincent.

However, only sixteen soils were analysed in this instance and only the surface 0 - 15 cm depth in each case. The results of the analysis are in accordance with those presented in Part II of this study. One important variation is that there were not the convincing evidence of residual effects of previous fertilizer use, since these were food crop farms which were not as heavily fertilized as banana cultivations.

Barker, G.H. 1981. St. Vincent: An agricultural profile. Caribbean Agricultural Research and Development Institute, UWI Campus, Mimeo Report. 24 pp. (See Attachment 46) This report presents much information on agriculture in St. Vincent including summaries of the production levels of the various agricultural commodities. An out-dated land use map is included. The environmental factors such as topography, vegetation and climate are considered in summary. The soils are described according to the groupings of Hardy and Beard (1954) and Watson et al. (1958).

Smith, G.D. 1983. Soil and Land Use Surveys No. 27. Correlation of the soils of the Commonwealth Caribbean, Puerto Rico, the Virgin Islands and Guyana.

Department of Soil Science, Faculty of Agriculture, The University of the West Indies, Trinidad. (See Attachment 47) In this publication, the soils of the Caribbean territories including St. Vincent were correlated and classified according to the comprehensive system of soil classification known as Soil Taxonomy. The classification was done by Dr. G.D. Smith of the USA, the main author and authority of the system of soil classification. The classification of the soils previously was at the series level which is the lowest category into which a soil unit can be classified. In the publication being referred to, the individual soil series were classified into the higher categories of classification i.e. Families, Subgroups, Sub-orders and Orders; this has placed the classification of the soils of St. Vincent at an international level.

Since this classification was published, there has been comprehensive revisions of the classification of some of the Soil Orders particularly the Inceptisols and the creation of the new Order Andisols for soils derived from volcanic materials.

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These changes in the classification would impact on the classification of the St. Vincent soils and therefore the need exists for a reclassification of the soils.

However, before this can be done, the individual soils must be re-described since the available descriptions are incomplete; the soils must also be re-analysed for characterization purposes using up to date methodology.

Ahmad, N. 1984. A synopsis of soil and land use report for St. Vincent.

Caribbean Agricultural Research and Development Institute, UWI Campus.

Mimeo Report. 25pp. (Attachment 48) This is a summary of the Soil and Land Use Report No. 3 by Watson et al.

(1958). Additional information has been included such as the classification of soils according to soil taxonomy (Smith, 1983). Up-dated information on land use was also included, taking cognizance of the disappearance of sugarcane and cotton as commercial crops; the relative decline of arrowroot, the introduction of banana as a commercial crop and its rapid spread and the recent greater emphasis on food crop production with emphasis on exports, have all impacted on the use of the land and resulted in some competition for the various uses. It was noted that an up-to-date land use and crop distribution map was not available for the island and it would be useful if one can be made.

Sections on soil behaviour i.e. soil fertility and soil physical properties and soil erosion have been added.

This report is written for readers interested in the land and not only for soil scientists. Much of the available information was summarized and presented in tabular form for easy reading.

Ahmad, N. 1987. Land capability of St. Vincent and the Grenadines (Bequia).

The Organisation of American States, Washington, D.C. 130 pp. (See Attachment 49) This study consisted of two parts as follows: (i) Land capability classification for St. Vincent. (ii) Soil and land use survey and soil mapping for Bequia and a capability classification of the soils of this island. (i)

Land capability of St. Vincent The capability classification proposed by the USDA was used in general outline but the parameters for classifying the soils were based on the realities of local conditions. For instance the requirements and importance of complete agricultural mechanization was discounted since this cannot be achieved in St. Vincent. The properties of the individual soils especially with respect to their structural stability and relative resistance or 53

susceptibility to erosion were adequately considered. Limiting factors such as exposure of soils to high winds, excessive relief, depth and nature of the underlying parent material and any impediments to root growth which are characteristic of St. Vincent soils were also considered.

At a more practical level, the relative capabilities of the soils for particular crops were presented. The prospects for increased crop production and the importance of tree crops and managed forests were considered.

The capability classification was mapped on a scale of 1:25,000 and much more topographic information was given compared to the soil map of Watson et al. (1958). (ii)

The soil survey of Bequia was carried out on a scale of 1:10,000 and a soil map prepared. Seven soil series were identified and mapped and soil characterization analyses have been presented.

The land capability classification for Bequia was done along the same lines as for St. Vincent in which the relative suitability of the various soils was particularly considered.

The information and data collected for the two islands were summarized in tabular form and the following tables of data are in the report: Table 1: Table Table Table Table Table

3: 4: 5: 6: 7:

Table 8:

pH soil fertility and limiting factors of the soils of St. Vincent (0-15 cm depth) Some properties of the soils of Bequia Classification of the soils of St. Vincent Relationship of slope and land capability classes of the soils of St. Vincent.

Acreages in the various slope categories of the soils of St. Vincent Acreages of the capability classes and Sub-classes of the soils of St. Vincent.

Acreages of the various land capability Classes and Sub-classes in the dominant watersheds.

As useful and informative as this report may be for St. Vincent, it was never published and used. There is only one copy each of the report, the land capability map of St. Vincent, the soil map of Bequia and the land capability map of Bequia at the office of the Organisation of American States in Kingstown, St. Vincent. The colours on the maps are now somewhat faded but it is not too late to save the information. It is most strongly recommended that this be done; however, it would be most important, in this event, that the information

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presented be revised and up-dated. This would not be a major task, however important.

Orban, C.M. and Matadial, W. 1989. Fertilizer trials on selected root crops in St. Vincent. Paper presented at the 25th Annual Meeting of the Caribbean Food Crops Society, Guadeloupe, FWI. July 2 - 8, 1989: 24 pp; Proc. 25 Annual Conference of the Caribbean Food Crops Society. INRA, Guadeloupe, FWI: 335-354. (See Attachment 50) Fertilizer trials were conducted on tumeric, ginger, eddo and sweet potato in a range of agro-climatic ecozones and soil series in St. Vincent. These trials were not replicated and each larger plot (6.66m x 6.66m) was divided into four subplots (3.33m x 3.33m). To the sub-plots were applied three different fertilizer blends 18:18:5, 16:18:24 and 16:8:24 at a rate of 1000 kg/ha; the fourth subplot was the control. None of the fertilizer blends consistently produced the highest yields for any crop or soil type. There was a major difference in yield (sometimes more than 100 percent) between the no fertilizer and the fertilized plots for all the crops. However no statistical analysis of the results was possible.

From a soil physical aspect, the soils of St. Vincent are ideally suited for root crops and products of high quality are grown. Yet there has been very little record of research being done to improve these crops or to study to what extent yields can be increased by fertilizer use. Even for arrowroot which is a staple crop, there is a great scarcity of information in this regard. The study referred to above was not very scientifically planned and executed but it is one of the few on record.

Production of root crops can be much more important in the agriculture of St. Vincent and it may now be appropriate to plan and carry out a comprehensive programme of research aimed to improve crop productivity and quality and value addition to the products.

Visser, L. 1989. Geographic aspects of phosphate fixation on St. Vincent, West Indies. M.Sc. Thesis, Department of Geography, University of Calgary, Calgary, Alberta. 175p. (See Attachment 51) This is a study of the occurrence of phosphorus and forms which occurs on the soils of St. Vincent. In sampling the soils for phosphorus fractionation studies, the island was divided into geographic zones and sub-zones with the hope that these zones would represent different levels of soil development which would in turn influence the forms in which phosphorus occurs in the soils. The analytical work was well done; it was carried out at the Department of Soil Science of the University of the West Indies by this writer.

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The results showed that total phosphorus was not necessarily low but there was a wide range of values in the various zones and sub-zones not only in total phosphorus but in the various fractions such as organic aluminium, iron and calcium bound and occluded phosphorus.

The premise on which the geographic zoning of the sampling sites that there were significant age differences in the various soil groups was probably not well founded since, although underlying parent materials differed in age, there were significant superficial deposits of volcanic ash over the whole island. This new material would have been progressively incorporated in the soil profile; it was noted that only up to 50 cm depth of soil was sampled.

Also, no account was taken, in the selection of sample sites, of the previous agricultural history of the location and the probable use of phosphate fertilizer in the past. In St. Vincent this could be a major factor in determining the phosphorus status of the soils at any location. It is also regrettable that the so called “available” phosphorus was not determined at the same time using an appropriate method(s) as this would have facilitated the correlation of any of the phosphorus fractions with the available form. Although the coordinates of the sample sites are provided in the thesis, the actual soils sampled were not given.

The only information given was whether the site corresponded to high level or low level yellow earth or recent volcanic ash, which are themselves very broad and indistinct groupings.

Research of the nature done by Visser would be very useful and informative if the sites selected were chosen on the basis of similarity of the soils, the history of land use and soil management and also if some correlation could be established between the various chemical forms and the available fraction.

Limburd, A. 1990. Leader, Small Islands Research Group, Department of Geography, University of Calgary, Alberta, Canada. (See separate package – Attachment 52) This collection consists of a number of publications including three M.Sc. Theses.

The publications were not concerned directly with soil fertility problems but with aspects of the environment including soil erosion. The publications of this group which dealt more directly with soil fertility and soil management have been separately reviewed and are included in this report.

The research carried out by this Group on St. Vincent is quite substantial and it is important that the publications be kept and added to those on agriculture, soil fertility and soil management which form the main subject of this report.

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Orban, C.M. 1990. Patterns of variations in selected soil properties, St. Vincent, West Indies. M.Sc. Thesis, Department of Geography, University of Calgary, Calgary, Alberta. 127p. (See Attachment 53) Soil samples from 55 sites representing a variety of micro-climates and geographic parameters were tested for the selected nutrients nitrate nitrogen, ammonium nitrogen, phosphorus, potassium, calcium, magnesium, sulphate sulphur and iron. Nitrite nitrogen, organic matter content and soil pH were also determined. The samples were taken from five zones which were selected with respect to the original soil groupings of Watson et al. (1958) and each group was in the same rainfall regime but included different soil series. At each site, samples were taken at 10, 20 and 50 cm depth regardless of the existence of soil horizons. The aim of the study was to observe the variability that existed in these properties within each of the zones and with what environmental factors these can be correlated. The soil samples were analysed using a La Motte TRL-2 portable soil test kit. The self-contained system was chosen in light of the rudimentary laboratory facilities that existed on the island at the time.

The main conclusion from the study were that: Patterns of variation existed among the soil properties. Discrete clusters of soil variables tended to be associated with one another and each cluster included the same principal variables over each sample depth.

According to the author, elevation and associated rainfall regimes were the environmental parameters most closely associated with patterns of variations in soil properties.

The results were rather spurious and provided little help for improved soil management. Possible reasons for the spurious results were that the limits of the groupings or zones were too broad since different soil series were included and no attention was paid to the nature of the parent material. Also, there was no indication that soil slope was taken into account. Most importantly, previous land use history especially with respect to the banana crop was not considered in selection of the zones or sample sites. Another possible problem was the analytical methods used since La Motte soil test kits are more adaptable to providing some indication of soil fertility levels rather than for characterization purposes.

Future research on the variability of nutrient levels in St. Vincent soils can be quite useful and informative, but the most appropriate parameters in site selection should be studied.

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WINBAN. 1990. Fact sheet - Fertilizer use in banana production. Research and Development Division Communications and Documentations Unit, WINBAN, Roseau, St. Lucia (Attachment 54).

See WINBAN News, 1965 and attachment 21, this issue.

Limbird, A. 1993. A land capability classification index system for steep, tropical volcanic landscapes: a case of the Colonarie Watershed, St. Vincent, West Indies. Department of Geography, University of Calgary, Calgary, Canada. Typescript 27p. (See Attachment 55) This author agreed with Ahmad (1987) in adapting and modifying the USDA land capability classification in making some important changes to the traditional capability - soil - slope relationships. The main factors identified as rationale for the changes proposed are the exceptionally good physical properties of the St. Vincent soils, the suitability of the climate for all-year farming, the regeneration ability of the St. Vincent soils i.e. the application of the “rooting depth” rather than the solum and the steepness of slopes, anti-erosion potentials and the inherent skills of farmers.

Another system with potential reviewed by the author for St. Vincent and particularly the Colonarie Watershed was a treatment-oriented land capability classification developed for use in Jamaica. This system was based on slopes, depth of soils and necessary treatments for most intensive land use but there would be problems since in St. Vincent it was not practical to recommend that all soils on slopes 20˚ - 25˚ be used for pasture and those on slopes greater than 25˚ for forest.

A capability rating system as an alternative for the Colonarie Watershed and similar other watersheds was proposed in which ten parameters involving components of the site and soil were identified; the soil was ranked from 0 to 5 (very poor to excellent); the ratings were then summed and the aggregate was considered as the capability index. As an example of how the proposed system can function, the Colonarie Watershed was subdivided into 15 capability units and ranked for their capability indices.

The proposed system has merit; similar rankings have been proposed for Trinidad for example; using these and other parameters. However, a problem was the unavailability of data and information to realistically assign the rankings.

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Ewaschuk, C.M. 1995. Soil survey and land suitability classification with application of Geographic Information Systems: Union Island (St. Vincent and the Grenadines). M.Sc. Thesis, Department of Geography, University of Calgary, Calgary, Alberta, Canada. 159p plus map. (See Attachment 56) A soil survey was conducted on Union Island which has a land area of 838 ha.

The survey was intensive on scale 1:10,000 to provide relevant information pertaining to agriculture and agroforestry. The average annual rainfall of Union Island is 1078mm with severe dry seasons. The vegetation is dry scrub land and these features present a hostile environment for agriculture. Further, there is little or no scope for irrigation. In colonial times, cotton was the main crop grown and this use, together with effects of a harsh climate, caused catastrophic soil erosion and resulted in shallow, residual soils. The survey was conducted using geostatistical techniques and geographic information systems.

Eleven soils classified in the Orders Alfisol, Andisol, Entisol and Vertisol and two miscellaneous land types were identified and mapped. The soils were sampled and analysed for particle size, pH, electrical conductivity, organic matter, cation exchange capacity and exchangeable sodium percentage. Limited mineral analysis of the parent material using X-ray diffraction was carried out. the soils were qualitatively tested for the presence of allophane which was unnecessary in the particular climate since this mineral could not be synthesized in the conditions.

Incomplete description of the analytical methods used were presented; it is not known if the methods used were appropriate for soil characterization since no details of these were given.

The accuracy of the analytical data was exaggerated since values were given correct to two or three decimal places. The data was well presented and applied in the thesis, however.

A land suitability classification for agricultural use was attempted based on the information assembled; maps showing areas of relative suitability for tomato, cucumber, beans, sweet pepper, cabbage, cassava, maize, pigeon pea, pineapple, citrus, mango and coconut were presented. These would be found helpful as an initial guide to land use. The climate may well be too harsh for crops such as citrus and coconut and for even some of the other crops proposed.

Applications for forestry and agro-forestry have also been considered and a list of potential species was given; this could also serve as an initial guide. Finally, a generalized suitability of the various soils for agriculture, agroforestry and forestry as general usages was given.

The mapping of the soils seemed to be well done; however, the interpretive information needs to be reviewed from an agronomic, soils and environmental 59

aspect. The report needs to be summarized and simplified for general use. It may also be necessary to have the soils re-analysed using recognized methods for soil characterization. On the whole this is a very useful piece of basic work by the Geography Department of the University of Calgary.

Strand, J.T. 1996. Soil erosion in a Blue Mahoe (Hibiscus elatus) forest plantation and a secondary rainforest of the Colonarie River watershed, St. Vincent, West Indies. M.Sc. Thesis. Department of Geography, University of Calgary, Calgary, Alberta, Canada. (See Attachment 57) A ‘micro-scale’ soil erosion monitoring programme was set up in a blue mahoe (Hibiscus elatus) forest plantation and a neighbouring secondary rainforest of the Colonarie River Watershed, St. Vincent, West Indies. The main objective of the research was to quantitatively evaluate the effectiveness of the blue mahoe forest plantation in soil and water conservation in comparison to the secondary rainforest. Erosion study plots were set up in both forest types under similar topographic conditions and on the same soil type. Sediment loss, runoff and litter loss were measured using modified version of the ‘Gerlach Trough’.

Nutrient losses were determined by analyzing the eroded sediments for exchangeable forms of magnesium, calcium, sodium, potassium, iron, aluminium and manganese.

Runoff and sediment loss in the blue mahoe plantation was significantly greater than that of the secondary rain forest. This is attributed to the differing vegetation characteristics and slightly more erodible nature of the forest plantation soil. Concentration of sodium and iron were greater in the eroded sediments of the secondary rain forest, whereas, magnesium was greater in the plantation forest. Overall, the total loss of nutrients was 2.3 times greater in the forest plantation than in the secondary rain forest.

This was a worth-while study and more of this type of work should be done. The effect on soil erosion of two types of forest cover were measured but there was no way of comparing the effects of no ground cover with these two types of forest cover. It would have been also more useful to the reader if the losses of the various soil constituents were calculated on a per acre or per hectare basis in addition to the “study site”.

Campbell, V.A. 1999. Mount Wynne/Peter’s Hope Land Resettlement Project.

Land capability and suitability studies. Business, Research and Agricultural Consultants. c/o European Union, Kingstown, St. Vincent. (See Attachment 58) This report presents the results of a soil and land use study of the Mount Wynne/ Peter’s Hope and consisting of a land area of 162 ha. It was supposed to present in-depth and detailed data and information to support a land settlement 60

scheme. It seemed that the available information on soil distribution and land use presented by Watson et al. (1958) and Ahmad (1987) were largely extrapolated and recommendations were based on these, supported by limited field observations.

The soils occurring in the area were sampled and analysed for particle size distribution and chemical properties. However, the laboratory which carried out the analyses was not stated and the methods used were not given and therefore there is doubt about the reliability of the data.

The recommended crops and livestock for the various land capability classes seems reasonable.

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REFERENCES Sands, W.N. 1912. An account of the return of vegetation and the revival of agriculture in the area devastated by the Soufrière of St. Vincent in 1902 3. West Indian Bulletin 12:22 - 33. (Attachment 1)* Sands W.N. 1915. Method of working small holdings under the land settlement scheme, St. Vincent. West Indian Bulletin 14: 24 - 35. (Attachment 2) Harland, S.C. 1917. Manurial experiments with arrowroot in St. Vincent. West Indian Bulletin 16: 256 - 259. (Attachment 3) Harland, S.C. 1917. Manurial experimens with sea island cotton in St. Vincent with some notes on factors affecting the yield. West Indian Bulletin 16: 169-259. (Attachment 4) Harland, S. C. 1918. Manurial experiments with sea island cotton (1917-1918 experiments). West Indian Bulletin. 17: 69 â&#x20AC;&#x201C; 82. (Attachment 5) Hardy, F., Robinson, C.K. and Rogriguez, G. 1934. Studies in West Indian Soils VIII. The agricultural soils of St. Vincent. The Imperial College of Tropical Agriculture, St. Augustine, Trinidad, W.I. 44p. (Attachment 6) Hamilton, R.A. 1934. The application of mineralogical methods in the study of tropical soils. AICTA Thesis. The Imperial College of Tropical Agriculture, St. Augustine, Trinidad, West Indies. 20p. (Attachment 6a) Hardy, F. 1939. Soil erosion in St. Vincent, B.W.I. Trop Agric. (Trinidad) 16: 5865. (Attachment 7) Hardy, F. and Cripps, E.G 1944. Subsoil fertility of eroded volcanic ash in St. Vincent, B.W.I. Trop. Agric. (Trinidad) 21: 30 - 39. (Attachment 8) Hardy, F. 1945. Geology and Soils of British West Indies (i) St. Vincent; (ii) Grenadines. In F. Hardy 1945: Geology and soils of the Caribbean Region. Revised Edition. Mimeo Report. The Imperial College of Tropical Agriculture, Trinidad, West Indies. 5p (Attachment 9) Hardy, F. 1947. Phosphate deficiency in some West Indian soils as revealed by pot tests. Trop. Agric. (Trinidad) 26:85-92. (Attachment 10)

this refers to the publication number in the St. Vincent collection of publications on soils of the island provided separately. *

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Vernon, K.C. 1951. Soil survey report of Camden Park Experiment Station, St. Vincent. In: K.C. Vernon: AICTA Thesis. Imperial College of Tropical Agriculture (ICTA), St. Augustine, Trinidad. Library, U.W.I. 47 - 66. (Copy unavailable, no attachment) Hardy, F. and Beard, J.S. 1954. Soil formation in the British Caribbean Islands.

Department of Chemistry and Soil Science, The Imperial College of Tropical Agriculture, Trinidad. Mimeo Report 23 p and maps. (Attachment 11) Watson, J.P., Spector, J. and Jones, T.A. 1958. Soil and Land Use Surveys No. 3 St. Vincent. The Regional Research Centre (RRC), Imperial College of Tropical Agriculture, Trinidad, West Indies. 70p plus maps. (Attachment 12) Wright, A.C.S. 1959. A New Zealand Pedologist in the Caribbean (November 1958 - March 1959). V. St. Vincent. Mimeo report. 18p (Attachment 13) Hay, R.L. 1960. Rate of clay formation and mineral alteration in a 4000 year old volcanic ash soil in St. Vincent, B.W.I. Amer. Jour. Sci. 258: 354-368.

(Attachment 14) Cochrane, T.T. 1962. A study of the land use potential of two of the major soil types of St. Vincent, the high level yellow earth soils and the recent soils from volcanic ash. AICTA Thesis. Imperial College of Tropical Agriculture, St. Augustine, Trinidad 353 p. (Attachment 15) Regional Research Centre (RRC). 1962. Report on soil research. Mimeo report.

Soil and Land Use Section, The University of the West Indies, St. Augustine, Trinidad. 17p (Attachment 16) Regional Research Centre (RRC). 1962. Banana investigations. Mimeo Report.

Soil and Land Use Section. The University of the West Indies, St. Augustine, Trinidad, W.I. 37p (Attachment 17) Regional Research Centre (RRC). 1962. Arrowroot investigations. Soil and Land Use Section. RRC, U.W.I. St. Augustine, Trinidad. 17p. (Attachment18) Moss, P. and Coulter, J.K. 1964. The potassium status of West Indian soils.

Jour. Soil.Sci. 15:284 - 298. (Attachment 19) Twyford, I.T. and Coulter, J.K. 1964. Foliar diagnosis in banana fertilizer trials.

In: C. Bould, P. Prevot and J.R. Magness (eds.). Plant Analysis and Fertilizer Problems. 4; IRHO, Paris, 357-370. (Attachment 20)

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WINBAN news. 1965. Growing resistance to new fertilizer formula in St. Vincent.

WINBAN News Feb - April, 1965: 33 (Attachment 21) Partridge, I.J. 1965. A review of fertilizer experiments on food crops in the British Caribbean Territories 1935 - 1965. Diploma of Tropical Agriculture (DTA) Thesis. Library, The University of the West Indies, St. Augustine, Trinidad. (Photocopy not available â&#x20AC;&#x201C; no attachment) Twyford, I.T. 1967. Banana nutrition: A review of principles and practice. J. Sci. Fd. Agric. 18: 177 - 183. (Attachment 22) Walmsley, D. and Twyford, I.T. 1968. The zone of nutrient uptake by the Robusta banana. Trop. Agric. (Trinidad). 45: 113 - 118. (Attachment 23) Prashad, S. 1968. Physico-chemical properties of Caribbean Andepts with reference to potassium and ammonium fixation and release. M.Sc. Thesis, Department of Soil Science, The Library, The University of the West Indies, St. Augustine, Trinidad. (Attachment 24) Messing, J.H.L. 1969. Indications of sulphur deficiency in Windward Islands soils. Proceedings of a Soils Seminar held at UWI, Cave Hill, Barbados 29 30 May, 1969: 1 - 8. (Attachment 25) Walmsley, D., Cornforth, I.S. and Ahmad, N. 1969. Methods of estimating available nutrients in Windward Islands Soils. Department of Soil Science, University of the West Indies, St. Augustine, Trinidad. Report No. 15. 23p (Attachment 26) Ahmad, N. and Prashad, S. 1970. Dispersion, mechanical composition and fractionation of West Indian volcanic yellow earth soils (Andepts). Jour.

Soil Sci. 21:63-71. (Attachment 27) WINBAN Windward Islands Banana Growers Association Research and Development Division 1970 - 1992. Annual Reports. WINBAN, Castries, St. Lucia. (Reports available in St. Vincent, no attachment provided) Ihsan-ul-Haque 1971. The status of sulphur in West Indian soils. Ph.D. Thesis, Department of Soil Science. The Library, University of the West Indies, St. Augustine, Trinidad. (Attachment 28) Cornforth, I.S. and Walmsley, D. 1971. Methods of measuring available nutrients in West Indian soils I. Nitrogen. Plant and Soil 35: 389 - 399.

(Attachment 29)

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Walmsley, D., Twyford, I.T. and Cornforth, I.S. 1971. An evalution of soil analysis method for nitrogen, phosphorus and potassium, using banana.

Trop. Agric. (Trinidad) 48: 141 - 155. (Attachment 30) Baynes, R.A. 1972. Guidelines for better peanut production in St. Vincent, W.I. Bull. No. 2, Regional Field Experimental Programme, Department of Soil Science, The Regional Research Centre, The University of the West Indies, St. Augustine, Trinidad, W.I. Report No. 2. 9p. (Attachment 31) Hatten, C. 1972. St. Vincent II. Geomorphology and soils studies, the Yamba river basin including high level yellow earth (Montreal and Greggs) and low level (Akers) yellow earth. Department of Soil Science, The University of the West Indies, St. Augustine, Trinidad, W.I. 21p. (Attachment 32) Hatten, C. 1972. St. Vincent III: Geomorphology and soils studies of the Brighton area having prolonged dry season. Department of Soil Science, The University of the West Indies, St. Augustine, Trinidad, W.I. 16p.

(Attachment 33) Baynes, R.A. and Walmsley, D. 1973. Fertility evaluation of some soils in the Eastern Caribbean. Department of Soil Science, University of the West Indies, St. Augustine, Trinidad. Report No. 17. 80p (Attachment 34) Walmsley, D. and Cornforth, I.S. 1973. Methods of measuring available nutrients in West Indian soils II. Phosphorus. Plant and Soil 39: 91 - 101.

(Attachment 35) Ahmad, N., Cornforth, I.S. and Walmsley, D. 1973. Methods of measuring available nutrients in West Indian soils III. Potassium. Plant and Soil 39: 635 - 647. (Attachment 36) Twyford, I.T and Walmsley, D. 1973; 1974. The mineral composition of the Robusta banana plant. I. Methods and plant growth studies. Plant and Soil, 39: 227-243. (Attachment 37) Twyford, I.T and Walmsley, D. 1973; 1974. The mineral composition of the Robusta banana plant. II. The concentration of mineral constituents. Plant and Soil 41 (1974): 459-470. (Attachment 38) Twyford, I.T and Walmsley, D. 1973; 1974. The mineral composition of the Robusta banana plant. III. Uptake and distribution of mineral constituents.

Plant and Soil 41 (1974): 471 - 491. (Attachment 39)

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Twyford, I.T and Walmsley, D. 1973; 1974. The mineral composition of the Robusta banana plant. IV. The application of fertilizers for high yields.

Plant and Soil 41 (1974): 493-508. (Attachment 40) Baynes, R.A. and Walmsley, D. 1974. groundnut (Arachis hypogaea L).

(Attachment 41)

Mineral nutrition of the St. Vincent Trop. Agric. (Trinidad) 51: 27 â&#x20AC;&#x201C; 35.

Macfarlane, M. 1974. Phosphate studies on volcanic ash soils from St. Vincent.

Ph.D. Thesis: Department of Soil Science, The Library, University of the West Indies, St. Augustine, Trinidad. (Attachment 42) Warkentin, B.P. and Maeda, R. 1974. Physical properties of allophane soils from the West Indies and Japan. Soil Sci. Soc. Amer. Proc. 38: 372 - 377.

(Attachment 43) Macfarlane, M. and Walmsley, D. 1977. Effect of soil solution phosphorus in volcanic ash soils on the response of tomato (Lycopersicum esculentum) to added phosphates. Plant and Soil 47: 547-558. (Attachment 44) Ahmad, N. 1981. An investigation of soil conditions of farmersâ&#x20AC;&#x2122; holdings in St. Vincent. Consultant Report No. 8. The Caribbean Agricultural Research and Development Institute, The University of the West Indies Campus, St. Augustine, Trinidad, West Indies. (Attachment 45) Barker, G.H. 1981. St. Vincent: An agricultural profile. Caribbean Agricultural Research and Development Institute, UWI Campus, Mimeo Report. 24 pp.

(Attachment 46) Smith, G.D. 1983. Soil and Land Use Surveys No. 27. Correlation of the soils of the Commonwealth Caribbean, Puerto Rico, the Virgin Islands and Guyana.

Department of Soil Science, Faculty of Agriculture, The University of the West Indies, Trinidad. (Attachment 47) Ahmad, N. 1984. A synopsis of soil and land use report for St. Vincent.

Caribbean Agricultural Research and Development Institute, UWI Campus.

Mimeo Report. 25p. (Attachment 48) Ahmad, N. 1987. Land capability of St. Vincent and the Grenadines (Bequia).

The Organisation of American States, Washington, D.C. 130 p.

(Attachment 49)

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Orban, C.M. and Matadial, W. 1989. Fertilizer trials on selected root crops in St. Vincent. Paper presented at the 25th Annual Meeting of the Caribbean Food Crops Society, Guadeloupe, FWI. July 2 - 8, 1989: 24 pp; Proc. 25 Annual Conference of the Caribbean Food Crops Society. INRA, Guadeloupe, FWI: 335-354. (Attachment 50) Visser, L. 1989. Geographic aspects of phosphate fixation on St. Vincent, West Indies. M.Sc. Thesis, Department of Geography, University of Calgary, Calgary, Alberta. 175p. (Attachment 51) Limburd, A. 1990. Publication of the Small Islands Research Group (SIRG), Leader A. Limbird. Department of Geography, University of Calgary, Alberta, Canada. (Attachment 52) Orban, C.M. 1990. Patterns of variations in selected soil properties, St. Vincent, West Indies. M.Sc. Thesis, Department of Geography, University of Calgary, Calgary, Alberta, Canada. 127p. (Attachment 53) WINBAN. 1990. Fact sheet - Fertilizer use in banana production. Factsheet.

Windward Islands Banana Growersâ&#x20AC;&#x2122; Association Research and Development Division Communications and Documentations Unit, WINBAN, Roseau, St. Lucia. 4p. (Attachment 54) Limbird, A. 1993. A land capability classification index system for steep, tropical volcanic landscapes: a case of the Colonarie Watershed, St. Vincent, West Indies. Department of Geography, University of Calgary, Calgary, Canada.

Typescript 27p. (Attachment 55) Ewaschuk, C.M. 1995. Soil survey and land suitability classification with application of Geographic Information Systems: Union Island (St. Vincent and the Grenadines). M.Sc. Thesis, Department of Geography, University of Calgary, Calgary, Alberta, Canada. 159p (Attachment 56) Strand, J.T. 1996. Soil erosion in a blue mahoe (Hibiscus elatus) forest plantation and a secondary rainforest of the Colonarie River watershed, St. Vincent, West Indies. M.Sc. Thesis. Department of Geography, University of Calgary, Calgary, Alberta, Canada. (Attachment 57) Campbell, V.A. 1999. Mount Wynne/Peterâ&#x20AC;&#x2122;s Hope Land Resettlement Project.

Land capability and suitability studies.

Business, Research and Agricultural Consultants. c/o European Union, Kingstown, St. Vincent.

(Attachment 58)

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