Annals of the Sri Lanka Department of Agriculture. 2008.10:97-103.
POTENTIAL OF MAIZE (Zea mays) AND CHILLI (Capsicum annum) INTERCROPPING UNDER SUPPLIMENTARY IRRIGATION M.A.P.W.K. MALAVIARACHCHI1, W.D. LESLY2, S.N. JAYAWARDANE3 and D.M.G. ETHAKADE1 1 Field Crops Research and Development Institute, Mahailluppallama 2 Fruit Crops Research and Development Centre, Horana 3 Rice Research and Development Institute, Bathalagoda
ABSTRACT The potential of intercropping chilli with maize was studied in yala 2000 and maha 2000/01 at the Field Crops Research and Development Institute Mahailluppallama with five treatment combinations viz. maize sole crop for green cobs (system I), maize sole crop for seeds (system II), chilli sole crop (system III), intercropping chilli with maize for seeds (system IV) and inter-cropping chilli with maize for green cobs (system V). In inter-cropping combinations, maize was planted at the spacing of 120 cm x 30 cm maintaining two plants per hill. Two rows of chilli were planted between two maize rows at 40 cm apart from each row with 60 cm intra-row spacing leaving two plants per hill. The spacing used in mono cropping was 60 cm x 30 cm for maize and 60 cm x 45 cm for chilli. Light availability under intercropped maize was 20%-25% higher than that in mono-cropping. However, the transmitted light available for chilli under intercropped maize was 39%-44% lower than the total light intensity received for sole chilli crop. Leaf nitrogen content in intercropped maize was higher than the mono cropping. The highest economic advantage was obtained from system I (Rs. 124655, Rs. 111176) while the second highest (Rs 85857, Rs. 45807) was obtained from system V. Therefore, out of tested systems sole maize crop grown for green cobs is the best mono cropping system while chilli intercropped with maize for green cobs is the best intercropping system. KEYWORDS: Chilli, Maize, Productivity.
INTRODUCTION Growing more than one crop simultaneously on a given land improves crop productivity by efficient utilization of environmental resources. Crops in a mixture may entertain a better advantage in exploiting more mutual benefits while farmer can eliminate certain risks incurred with mono cropping systems. Mixed cropping of two or more crops is the most popular form of farming especially, in subsistence tropical agriculture (Hamblin and Zimmermann, 1986). These systems play a vital role in small scale farming where the primary intention is to maximize productivity and utilization of the available land area with long term sustainability. This has a particular significance where land resources are extremely limited. Most of the farmers in Sri Lanka are small scale farmers having less than 1 ha of land allotments. Research information on mixed cropping systems would be quite useful for these framers to increase their crop yields along with maximized profit margins.
98 MALAVIARACHCHI et al.
Maize is the second most demanding cereal crop in Sri Lanka which is consumed either as grains or as green cobs. Among the major other field crops grown by small scale farmers, maize has received prominent attention in the recent years. Despite the increasing annual production witnessed over the last few years, a large quantity of grains is still imported to meet the deficit of the national requirement. Although green cobs have a similar demand, information on the cultivated extent, production and sales of green cobs are hardly available. Green cobs are mainly produced by small scale farmers due to its ready disposal to the market. Chilli, on the other hand, is one of the most important cash crops grown mainly in the dry zone. It has been reported that the chilli extent has been gradually declining over the last several years (AgStat, 2006) due to low yields resulting from high pest and disease incidence coupled with high cost of production (Personal communication, 2007). Nearly fifty percent of the cultivated extent of chilli in the dry zone is grown under rainfed condition while the rest with supplementary irrigation in lands of less than 1 ha in extent. Input costs of all crops are ever increasing whereas the market prices remain naturally stagnant. Under these circumstances, a suitable combination of cash crops grown together on the same piece of land would be a plausible alternative to reach the higher profit margins. The popular system of intercropping involves growing of a cereal and a legume considering the mutual agronomic and physiological advantages of both crops (Gunasena et al., 1979). However, other combinations of crop groups have also been attempted on several occasions. There is a potential of intercropping chilli with several leguminous and nonleguminous crops (Techno-guide, 1990) and maize with many leguminous crops (Santalla et al., 1994; Gunasena, 1982). Previous intercropping studies have focused attention on crop combinations of maize with several legumes, but hardly with chilli (Gunasena, et al., 1979). Therefore, potential of intercropping chilli with maize was investigated in this study with the objective of increasing farmers’ profit through maximizing the resource use efficiency. MATERIALS AND METHODS The experiment was conducted in yala 2000 and maha 2000/01 seasons at the Field Crops Research and Development Institute Mahailluppallama in upland soils with an irrigation interval of 10 days in maha and 5 days in yala. Five treatments, consisting either a sole crop or mixed crops viz 1.) Maize sole crop for green cobs (system I), 2.) Maize sole crop for seeds (system II) 3.) Chilli sole crop (system III).4) Inter-cropping chilli with maize for seeds (system IV) and 5.) Inter-cropping chilli with maize for green cobs (system V) were arranged in a Randomized Complete Block
INTERCROPPING OF MAIZE AND CHILLI 99
Design with five replicates. Plot size was 6.0 m x 4.5 m. Planting arrangement of each system is given in the Table 1. The maize variety used in each system was Aruna while the chilli variety was MI-2. Table 1. Planting arrangement of each system. Cropping pattern Sole cropping Intercropping
Spacing Maize
Chilli
60 cm x 30 cm 120 cm x 30 cm
60 cm x 45 cm 40 cm x 60 cm
No. of plants/ hill Maiz Chilli e 1 2 2 2
Plant density/ ha Maiz Chilli e 55555 74074 55555 83333
Both crops were fertilized separately according to the recommendations made by the Department of Agriculture, Sri Lanka, viz.150 kg/ha of nitrogen, 45 kg/ha of P 2O5 and 60 kg/ha of K2O for chilli and 150 kg/ha of nitrogen 45 kg/ha of P2O5 and 30 kg/ha of K2O for maize. In calculating the income for the system I and V, the maize yield was measured in terms of green cob number assuming that there were no differences in the cob size while in other systems where maize yield was obtained as grains, it was expressed in kilograms. Light interception across the canopy was measured using Tube Solorimeters (Szeicz et al., 1964: Monteith, 1993) at vegetative (3 WAS - 7 WAS) and reproductive (7 WAS - 12 WAS) stages during the day time at 1 hour intervals and added to get the cumulative value. A sample of 10 randomly selected plants from each plot was used to collect leaves for leaf nitrogen measurements 60 days after crop establishment in both crops. Nitrogen content of leaves were analyzed following the Kjeldhal method using the leaf at the cob height for maize (Blackber and Schepears, 1995) and total leaves of the plant were used for chilli. Finally a cost benefit analysis was done following the partial budget technique (CIMMYT, 1988). RESULTS AND DISSCUSION Total incoming radiation available at the top of the canopy for all systems during vegetative and reproductive stages was 762.30 MJ/m 2 and 623.70 MJ/m2 respectively. Transmitted light through the sole and intercropped maize canopy at vegetative and reproductive stages at two different heights from the ground level is shown in Table 2. Light availability under intercropped maize was around 20%-25% higher than that in monocropping and this could be accounted for the altered spacing adopted for intercropping However, the transmitted light available for chilli under intercropped maize was 39%-44% lower than the total light intensity received for sole chilli crop.
100 MALAVIARACHCHI et al. Table 2. Transmitted radiation available under the maize canopy (MJ/m2). System
Vegetative
Reproductive
Sole crop at 45cm height 370.0 c 279.90 c Sole crop at 30cm height 335.09 d 260.47 d Intercrop at 45cm height 463.36 a 346.50 a Intercrop at 30cm height 402.9 b 320.84 b CV% 3.76 3.11 Means followed by the same letter in each column are not significantly different at p=0.05.
Leaf nitrogen content (Table 3) in maize under intercropping systems was compared and it was revealed that the nitrogen content of respective intercropped maize crops were higher than that of the mono cropping situations. This indicates that part of the nitrogen applied to chilli crop has been absorbed by the maize crop. Low leaf nitrogen contents in chilli grown under intercropping situations, compared to the sole crop indicate that maize competes with chilli for nitrogen. The combined effect of this low nitrogen and reduced light availability under intercropped systems has resulted in low yields from intercropped chilli resulting in comparatively low net returns. Table 3. Leaf nitrogen content (%) of each crop under different systems. System
Maize
Chilli
Maize sole crop for green cobs (System I) 2.34 b Maize sole crop for seeds (System II) 2.08 b Chiili sole crop (System III) 1.84 a Chilli + Maize for seeds (System IV) 3.31 a 1.18 b Chilli + Maize for green cobs (System V) 2.93 a 1.24 b CV % 12.5 12.2 Means followed by the same letter in each column are not significantly different at p=0.05
The yields were converted into financial terms by calculating income based upon the yields of each crop in each system (Table 4). Price of chilli, maize seeds and green cobs used in computation were Rs.114.00/kg, Rs. 20.00/kg and Rs. 4.00/cob respectively. The highest income was generated by system V followed by the system III, IV and I while the lowest was obtained from the system II (Table 5).
INTERCROPPING OF MAIZE AND CHILLI 101 Table 4. Yield of each crop in each system during two growing seasons. System Maize sole crop for green cobs (System I) Maize sole crop for seeds (System II) Chiili sole crop (System III) Chilli+Maize for seeds (System IV) Chilli+Maize for green cobs (System V)
Maize (Grain yield in kg) maha yala 4539 b
4418 b
5964 a
5646 a
-
-
Maize (Green cob number) maha yala 42216 a 39352 a
Chilli (kg) maha -
yala -
-
-
-
-
1990 a
2017 a
-
-
532 c
676 b
842 b
540 b
44540 a
45100 b
-
-
CV % 13.8 13.8 13.0 6.0 12.8 16.9 Means followed by the same letter in each column are not significantly different at p=0.05 Table 5. Gross income from different cropping systems (Rs./ha). System Maize sole crop for green cobs (System I) Maize sole crop for seeds (System II) Chiili sole crop (System III) Chilli+Maize for seeds (System IV) Chilli+Maize for green cobs (System V)
maha 2000/01 168864 90780 226860 179928 274148
yala 2001 157408 88360 229938 189984 241960
However, the cost of production varies among crops as well as among different systems because of the varied demands on inputs and the varied agronomic management practices. Therefore, a real conclusion on which system brings more economic advantage, should be based upon a cost benefit analysis (Table 6). The total cost incurred on each crop under supplementary irrigation (Anon., 2005) and the income from each system (Table 4) was used in the economic analysis. The highest economic return (Rs. 124655 and Rs. 111176) was obtained from system I (maize grown for green cobs) both in maha and yala seasons while the second and third highest returns (Rs. 85857, Rs. 45807 and Rs. 41206 Rs. 36763) were obtained from system V (chilli intercropped with maize for green cobs) and system II (maize grown for seeds)) respectively. Though the third highest income was obtained from intercropping chilli with maize for seeds it has given a negative economic return owing to low income generated from low chilli yields at a high cost of production. Therefore, out of tested systems, sole maize crop grown for green cobs is the best mono cropping system while chilli intercropped with maize for green cobs is the best intercropping system. Further, an additional advantage that could be obtained from the system V is that once the maize is harvested for green cobs the crop residue could be applied as mulch to conserve soil moisture for the advantage of the companion crop chilli. Dharmasena (1995) pointed out that use of rice straw as surface
102 MALAVIARACHCHI et al.
mulch at the rate of 8 mt/ha (dry matter basis) could reduce the total irrigation requirement by 40 percent compared to unmulched plots of chilli. The total cost decreased in system V compared to mono-cropping of both crops was 20% because when it was inter-cropped several cultural practices such as land preparation, weeding, irrigation could be coupled. Table 6. Gross income, total cost of cultivation and net return as affected by different systems. System
Gross income (Rs/ha) maha yala 168864 157408
1
Total cost (Rs/ha)
Net return (Rs/ha)
2
maha yala maha yala Maize for green cobs 44209 46232 124655 111176 (System I) Maize sole crop for 90780 88360 49574 51597 41206 36763 seeds (System II) Chilli sole crop 226860 229938 196550 202389 30310 27549 (System III) 3 3 Chilli+ Maize for 179928 189984 193656 201518 -13728 -11534 seeds (System IV) 3 3 Chilli+ Maize for 274148 241960 188291 196153 85857 45807 green cobs (SystemV) 1 Including family labour 2 Irrigation cost was reduced by half due to rain 3 Irrigation, land preparation and weeding was considered as common practices and cost was taken only from maize
CONCLUSIONS There is a potential to inter-crop maize and chilli under supplementary irrigation both in yala and maha seasons. Inter-cropping chilli with maize for green cobs increases the productivity and profitability compared to sole chilli crop, sole maize crop for seeds and chilli intercropped with maize for seeds. However, the highest net return could be obtained from sole maize crop grown for green cobs. REFERENCES Anon., 2005. Cost of cultivation of agricultural crops, yala, 2005. Socio Economic and Planning Centre, Department of Agriculture, Peradeniya, Sri Lanka. 63-67p. AgStat, 2006. Volume III. Pocket book of agricultural statistics. Socio-Economic Planning Centre, Department of Agriculture, Peradeniya, Sri Lanka. 16-20p. Blackber, A.M. and J.S. Schepears. 1995. Use of chlorophyll meter to monitor N status and schedule fertigation for corn. Journal of Production Agriculture 8: 56-60. CIMMYT. 1988. From agronomy data to farmer recommendation. An Economic Training Manual. Completely revised edition. Mexico. D.F. 20-29.
INTERCROPPING OF MAIZE AND CHILLI 103 Dharmasena, P.B. 1995. Mulching for water conservation in agro-well farming. Farming. In Proceeding of the 51st SLAAS annual session, Sri Lanka. 191-192p. Gunasena, H.P.M. 1982. Performance of a maize-legume intercrop system in Sri Lanka. In Proceedings of the Second Symposium on Intercropping in Semiarid Areas held at Morogoro, Tanzania, 4-7 August 1980. Pp72-73. Eds. C.L. Keswani and B. J. Ndunguru. International Development Research Center, Ottawa, Canada. Gunasena, H.P.M., R. Sangakkara and Preethi Wikramasinghe. 1979. Studies on cereallegume intercrop systems. Journal of National Science Council of Sri Lanka 7(2): 85-94. Hamblin, J. and M.J.O. Zimmermann. 1986. Breeding common beans for yield in mixtures. Plant Breeding Review 4: 245-270. Monteith, J.L. 1993. Using Tube Solarimeters to measure radiation interception by crop canopies and to analyze stand growth. Document code TSL-AN-4-1. DeltaT devices. 7-9p. Personal Communication. 2007. Mr. K.N. Kannangara, Research Officer. Field Crops Research and Development Institute, Department of Agriculture, Mahailluppallama, Sri Lanka. Santalla, M., A.M. de Ron, M.R. Escribano. 1994. Effect of intercropping bush bean population with maize on agronomic traits and their implications for selection. Field Crops Research 36:185-189. Szeicz, G., J.L. Monteith and J. DOS Santos. 1964. A Tube Solorimeter to measure radiation among plants. Journal of Applied Ecology 1:169-174. Technoguide. 1990. Department of Agriculture Sri Lanka. 136-150p.