Integrated Use of Poultry Manure and NPK Fertilizer on Soil Properties and Cocoyam Production

The increasing food security and industrial demand for cocoyam has compelled soil Scientist to evaluate the use of organic and inorganic fertilizers alone or in combination to enhance early establishment, canopy development and yield of cocoyam (Colocasia esculenta L. Schott.). In this study, integrated use of chemical fertilizer (N) with poultry manure (PM) as amendments at different rates on soil physical and chemical properties and cocoyam production in coastal plain soil was investigated. Treatments were: Control- (PM0N0), 5 t ha-1 PM (PM5N0), 10 t ha-1 PM (PM10N0), 200 kg NPK ha-1 (PM0N200), 100 kg NPK ha-1 (PM0N100), 2.5 t PM + 100 kg NPK ha-1 (PM2.5N100) and 5 t PM + 100 kg NPK ha-1 (PM5N100). Results revealed that physical and chemical properties of the soil and cocoyam yield were substantially (p < 0.05) improved by applications of 10 t ha-1 (PM10) poultry manure and a combinations of lower rates (PM5N100). Water holding capacity, total porosity and soil organic matter were substantially increased by 64%, 30% and 72% respectively by the applications of 10 t ha-1 PM, and PM5N100. Saturated hydraulic conductivity was significantly (p < 0.05) higher in PM5N100 (25.8 cm h-1) followed by PM10N0 treatments (24.11 cm hr-1). The PM5N100 treatment also gave the highest yield of cocoyam (4.8 kg m-2) with maximum leaf area index of 96%, sufficient to protect the soil surface from the impact of high tropical rains. In this study, integration of NPK (15:15:15) at 100 kg ha-1 with 5 t ha-1 poultry manure can be used to improve the soil structural indices and increase yield of cocoyam and allied crops on sustainable basis.