Combined used of Dry Cocoa Bean Test Ash (Theobroma cacao L.) and Poultry Dropping for the Improvement of Soil Fertility and Maize (Zea mays L.) Growth and Yield on a Humid Alfisol Southwestern, Nigeria

The combine use of dry cocoa bean testa ash and poultry droppings for the improvement of soil fertility, maize growth and yield was studied on an Alfisol south western Nigeria, located at Joseph Ayo Babalola University Ikeji-Arakeji, Ilesa Osun State, Nigeria. Research farm from April to July 2018 and from August to November 2018. Four treatments of poultry droppings (PD) at 5 tones ha-1, cocoa bean testa ash (CBTA) ash at 5 tones ha-1, mixture of poultry droppings and cocoa bean testa ash (PD + CBTA) at 2.5 tones ha-1 each and control (C) were used in a Randomized Complete Block Design (RCBD) with three replications. The study showed that organic manure is a valuable fertilizer and can serve as a suitable alternative to inorganic fertilizer in the south western Nigeria especially, CBTA that has higher concentration of potassium (K) and organic carbon (OC). Poultry droppings (PD 2.5 tones ha-1) treatments plus cocoa bean testa ash (CBTA 2.5 tones ha-1) produced higher values for plant height, leaf area, chlorophyll, leaf area index, plant diameter, cob length, cob diameter and grain yield against the control that recorded the lowest value. Also, CBTA improves soil pH (94%) and OC (87%) over the control as well as increases minerals such as N, P, K Ca, Mg, and Na at 19%, 37%, 19%, 53%, 43% and 36% respectively. Organic fertilizer applications increase maize growth towards the later stage and were significantly different from the control according to DMRT at p<0.05. Cocoa bean testa ash (CBTA) and poultry dropping (PD) application registered over 47% increases of N levels in the soil, from 0.15% to 0.77% to 0.84%. Organic carbon increased as poultry droppings plus cocoa bean testa ash were added to the soil. Maize grain yield increased from control plot to 1.95 t ha-1 in CBTA + PD plot. The study recommends an application rate of cocoa testa ash and poultry droppings for maize growth on this type of soil in this agro-ecology.