Effect of Npk and Poultry Manure on Cowpea and Soil Nutrient Composition

Field experiment was conducted at University of Agriculture, Makurdi in the Southern Guinea Savanna ecology of Nigeria to test effect of NPK fertilizer and Poultry manure on performance of cowpea and soil nutrient composition. The study conducted in 2008 and 2009 had a control, NPK 20 – 10 – 10 (48 kgha-1) and poultry manure (PM) with or without NPK fertilizer. The test soil was deficient in N and P. The PM, NPK and their combinations increased plant height, number of branches, leaves, dry matter yield (DMY), number of peduncles, pods, seeds and seed yield. The effect on plant height, DMY, number of pods and grain yield was significant. The 4 t ha-1 PM and 4 t ha-1 PM + NPK gave highest and similar seed yield. The PM alone or with NPK increased soil pH, N, P, K, Ca, Mg, CEC and O.M. The parameters increased with level of PM. Addition of NPK to PM increased soil N, P, K, Ca, ECEC, OM while NPK reduced pH. Application of PM at 4 t ha-1 is recommended.