Long Term Assessment of the Agronomic and Economic Benefits of Cocoa Food Crop Intercropping in the Absence of Fertilizer Application

摘要

Aim: To investigate the long term benefit of intercropping cocoa with some food crops with no fertilizer input. Study Design: Randomized complete block design with four replicates. Place and Duration of Study: Cocoa Research Institute of Ghana Substation at Bunso, between June 1998 and March 2011. Methodology: Plantain, cassava and maize were planted alone or as mixtures to give the following intercrop combinations: sole crop cocoa, cocoa/plantain, cocoa/cassava, cocoa/maize, cocoa/cassava/plantain, cocoa/cassava/maize, cocoa/plantain/maize and cocoa/plantain/cassava/maize. The girth and height of cocoa seedling, the yield of the food crops and cocoa, some physic-chemical properties of the soil and the profitability of the various combinations were assessed using analysis of variance. Percentage canopy development of cocoa under the various treatments was analyzed after square root transformation of the data. Results: Intercropping significantly (P<0.05) reduced the girth of cocoa seedlings in the cocoa/plantain combination only in the second year. The height of cocoa plant was not significantly influenced by the treatments. The cocoa/plantain/cassava/maize combination had the lowest but non-significant levels of N, P and K in the soil at the end of three years of food crop intercropping. Between 2001 and 2011, although the amount of harvested cocoa was not significantly affected by the treatments, cocoa beans from the intercrops was 28-60% more than the sole crop cocoa except in the case of the cocoa/cassava combination where there was a slight decrease in yield. Economic analysis of the treatments showed that intercropping was profitable. Higher net benefits were achieved where the combinations contained plantain and maize. Conclusion: Intercropping cocoa with food crops is beneficial since it generally increased cocoa bean yield and income even in the absence of fertilizer application. It is suggested that intercropping should be carried out during establishment to ensure increased productivity of the land.