Adejobi, K.B., Cocoa Research Institute of Nigeria, P.M.B. 5244, Ibadan, Oyo State, Nigeria; Famaye, A.O., Cocoa Research Institute of Nigeria, P.M.B. 5244, Ibadan, Oyo State, Nigeria; Adeniyi, D.O., Cocoa Research Institute of Nigeria, P.M.B. 5244, Ibadan, Oyo State, Nigeria; Orisajo, S.B., Cocoa Research Institute of Nigeria, P.M.B. 5244, Ibadan, Oyo State, Nigeria; Adeyemi, E.A., Cocoa Research Institute of Nigeria, P.M.B. 5244, Ibadan, Oyo State, Nigeria
The effect of different levels of cocoa pod husk ash and goat dung on nutrient uptake and growth performance of cashew (Anacardium occidentale) seedlings was investigated at Ibadan in the rain forest zone of Nigeria. The organic fertilizer treatments; cocoa pod husk ash(CPHA) and goat dung(GD) were applied at 6.5g of CPHA (5t/ha), 25g of GD (20t/ha) 12.5g of GD +6.5g of CPHA (10+5t/ha) 18.75g of GD + 6.5g of CPHA (15t+6.5t/ha), 25g of GD + 6.5g of CPHA (20t+5t/ha) 6.5g of GD+6.5g of CPHA (5t+5t/ha), 0.6g of urea (400kg/ha), per 2.5 kg of soil filled poly bag. The results showed that these organic fertilizers increased significantly (p<0.05) the growth parameters (plant height, stem diameter, leaf area leaf number, number of branch, root and shoot length, root and shoot dry weight and root and shoot fresh weight), soil and leaf N, P, K, Ca, Mg, Na soil pH and organic matter (O.M) compared to the control treatment. 20 t/ha of GD + 5 tons/ha of CPHA treatment had the highest values of cashew seedlings performance compared to 5t/ha CPHA, 20t/ha GD, 400kg / ha urea, and the control treatment respectively. For instance, combined application of 20t/ha of GD +5t/ha of CPHA increased the plant height, number of leaf, leaf area, stem diameter, number of branch, root and shoot length, fresh and dry root weight,fresh and dry shoot weight of cashew seedlings by 45%, 29%, 12%, 52%, 59%,34%, 32%, 14%, 14%, 33% and 17% respectively compared to sole application of 20 tons/ha of GD. When compared with urea fertilizer application, 20t/ha GD+5t/ha CPHA treatment also increased the plant height, number of leaf, leaf area, stem diameter, number of branch, root and shoot length, dry and fresh root weight, dry and fresh shoot weight of cashew seeding by 25%, 28% 9%,46%,59%,19%,18%,32%,14%,6% and 13% respectively. For leaf chemical composition of cashew seedlings, 20t/ha GD and 5t CPHA increased leaf N, P, K, Mg, Ca and Na by 57%, 22%, 27%,28%, 50%, and 56% respectively compared with the control. When compared with urea fertilizer treatment, 20t/ha of GD + 5 t/ ha of CPHA increased the leaf N, P, K, Mg and Ca by 18%,56%, 10% 12% and 20%, respectively. However, urea fertilizer increased leaf N, K, and Ca by 48%, 19%, and 38% compared to control treatment. For soil chemical composition, 20t/ha GD 5t/ha CPHA manure also increased the soil pH, OC, OM, N,P, K, Na, Mg and Ca by 18%,26%, 29%, 50%, 80%, 43%, 30%, 14%, and 9% respectively compared to urea fertilizer treatment. However, 20%t/ha GD + 5t/ha CPHA (25g GD+6.5g CPHA) was the most effective treatment in improving cashew seedlings performance, soil and leaf mineral composition. Therefore it could be recommended to cashew farmers.