Integrated Nutrient Management; Option for Improvement on Soil Chemical Properties, Growth and Yield of Cocoyam (Colocasia esculenta)

The response of cocoyam (Colocasia esuclenta (L.) Schott) and soil chemical properties to different manure sources were studied under field conditions in 2014 and 2015 cropping season at Federal College of Agriculture, Ishiagu, Ebonyi State, a derived savanna zone of Southeastern Nigeria. Randomized complete block design (RCBD) was used to study these soil amendments. Ten(10) treatments; 10t/ha poultry dropping (PD), 200 kg/ha NPK 15:15:15 fertilizer (NPK), 5 t/ha rice husk ash (RHA), 10 t/ha rice husk dust (RHD), 5t/ha PD + 2.5 t/ha RHA, 5 t/ha PD + 5 t/ha RHD, 100 kg/ha NPK + 2.5 t/ha RHA, 100 kg/ha NPK + 5t/ha RHD, 66.67 kg/ha NPK + 3.33 t/ha RHD + 1.67 t/ha RHA and control, were used in the study which were replicated three times. Soil chemical properties evaluated were pH, organic carbon, exchangeable bases (K+, Ca2+, Mg 2+ and Na+) and exchangeable acidity. Others include CEC, total nitrogen, available phosphorus and base saturation while cocoyam yield was measured at harvest. The results showed that soil pH, soil organic carbon (SOC), cation exchange capacity (CEC), exchangeable acidity (EA), BS and available phosphorous were significantly affected by the application of the amendments, while total nitrogen shows non-significant effect. Cocoyam cormels and corms yield were significantly (p < 0.05) increased in all the soil amended plots than the control. Generally, the results implied that the integration of organic and inorganic amendments stand better chance of improving soil fertility indices and the crop yield than their sole forms in the study.