Strengthening Cocoa Production through Site Specific Fertilizer Recommendation in Five Local Government Areas of Cross River State, Nigeria

Ten cocoa farms with declining productivity in five Local Government Areas (LGAs) of Cross River State, Nigeria were selected for rehabilitation purpose through appropriate fertilizer recommendation based on soil test values. The LGAs were Akpamkpa, Ikom, Efung, Boki and Obudu of which Yaunde (Ikom), Agbokim waterfall (Etung) and Orimekpang (Boki) are high cocoa producing areas, while Begiaba (Obudu) and New Ndebiji (Akamkpa) are medium cocoa producing areas. Each farm was divided into four blocks with eight sampling points where soil samples were collected at depths of 0-15 cm, 15-30 cm and 30-45 cm. Similarly, leaf samples were taken from the tree under whose canopy the soil samples were taken. The soil and leaf samples were processed and analyzed for nutrient compositions in the laboratory using standard laboratory procedures. Results indicated that soils of New Ndebiji and Orimekpang in Akamkpa and Boki Local Government Areas respectively contained 0.65 and 0.71 gkg-1 soil total N. These values are below the critical value for cocoa production. Hence, Nitrogen fertilizer will be necessary for optimum production in the two farms. Similarly, Potassium and Phosphorus are deficient in all the cocoa farms evaluated in the five LGAs. Leaf samples for N, P and K almost follow the trend of soil results. However, soil pH organic carbon, base saturation, CEC all fell within the acceptable range for cocoa production. The fertilizer computation based on the nutrient compositions of the soils indicated that Begiaba (Obudu) farm will require 41 kg P2O5/ha, and 188 kg K2O/ha with no Nitrogen fertilizer, New Ndebiji (Akampka) farm will need 23 kgN/ha, 27 kgP2O5 and 211 kg K2O/ha, Agbokim-waterfall (Etung) 41 kg P2O5/ha and 188 kgK2O/ha, Yaunde (Ikom) will require 94 kg P2O5/ha and 272 kg K2O/ha while Orimepang (Boki) requires 18 kgN/ha, 23 kgP2O5 and 13 K2O/ha. Soil pH had high negative and significant (p <0.01) correlation with soil available P in the various locations of study while the cocoa leaf N significantly correlated with leaf K (p <0.01). Non-acid forming fertilizers particularly organic based will be appropriate to achieve optimum productivity.