Yield And Rate Of Returns From Soil Fertility Management Practices For Coconut/Food Crop Combinations On Coastal Soils

Abstract

Intercropping of food crops in coconut palm plantations is a popular practice among coconut palm farmers in Nigeria. However, farmers are not guided by scientific information on the best combination of food crops and coconut palm. This study is designed to determine suitable crop combinations and fertility management practices for productivity and budgetary analysis of coconut-based farming system.The experiments were carried out between 1998 and 2007. The crop combinations tested were coconut/maize/cassava, coconut/cowpea/maize and coconut/maize/cassava/cowpea; and the fertilizer treatment were NPKMg (12:12:17:2) at 500kg/hectare and poultry manure at 2.5 tons/hectare. After 8 years of planting soil pH was fairly stable, while, available P and exchangeable K decreased, with the other cations increasing. This was attributable to preferential uptake of nutrients by the coconut and component crops. Coconut leaf area was increased by the inorganic and organic fertilizer, with the difference between the ‘no fertilizer’ application and application of NPKMg being significant (P < 0.05). Mean number of bunches per palm and number of nuts produced per hectare were not significantly increased by fertilizer treatment. However, there were increases due to crop combination, with combinations that include cowpea giving higher yields(2875 nuts) than those without (2118 nuts). Food crop yields were increased by the inorganic and organic fertilizers. The combination of coconut/maize/cassava/cowpea had the highest return per hectare (N222, 980) while coconut/maize/cassava combination recorded the least returns
per hectare (N26, 300) over the period. Gross margins within each combination were highest with application of NPKMg and lowest with no fertilizer application.