Effect of some organic fertilizers on soil and coffee (coffea arabica L.) leaf chemical composition and growth

An investigation was caITied out in the nursery at Akure, Nigeria, to determine the effectiveness of sole and amended wood ash, cocoa husk and rice bran with poultry, duck and turkey manures as sources of fertilizers on the growth of coffee (Coffea arabica) seedlings. Twelve manurial treatments; namely, cocoa pod husk, rice bran, wood ash (sole forms), rice bran + duck manure, rice bran + turkey manure and rice bran + poultry manure, wood ash + turkey manure, wood ash + duck manure, wood ash + poultry manure, cocoa pod husk + duck manure, cocoa pod husk + turkey manure and cocoa pod husk + poultry manure, were applied at 8liha (40 g pCI 10 kg soil filled poly bag), replicated three times, with an NPK fertilizer 400 kg/ha (2 g per bag) treatment. as a reference and a control (no fertilizer; no manure). The treatments were arranged in a completely randomizcd design. The results showed that the organic residues increased significantly (P0.05) plant height, leaf area, stem girth, number of leaves of seedlings, soil and leaf N, P, K, Ca and Mg, soii pH and organic matter (O.M.) contents relative to the control treatment. Wood ash + turkey manure treatment increased the soil N, P, K, Ca, Mg, pH and a.M. by 59%,23%,63%,99.8%,99%,30% and 92%, respectively, compared to NPK fertilizer treatment. Amended wood ash + turkey manure treatment also increased plant height, stem girth, leaf area, leaf number and shoot weight of the seedlings by 25.3% 21.4%, 6%, 13% and 16%, respectively, compared to the NPK fertilizer treatment. It also increased the leaf N. P, K, Ca and Mg by 67%, 49%,56%,60% and 67%, respectively, compared to the wood ash (sole) treatment. The reason for the best. performance of the amended wood ash with bird manures over their sole forms in coffee seedlings was due to their nutrient superiority. Turkey, duck and poultry manures have high nutrient contents and 52 low C/N ratio and their combinations with cocoa pod husk, rice bran and wood ash fortified their nutrients supplying power. The high soil K/Ca and K/Mg ratios in NPK fertilizer treatment led to imbalance in the supply of K, Ca and Mg nutrients to coffee. Wood ash + turkey manure applied at 8 t/ha was the most effective treatment in improving coffee growth parameters and leaf and soil chemical composition