Integrated soil nutrient management option for sustainable yam production

A study was conducted at the on-station in Fumesua (Forest) and Ejura (Forest-Savannah transition) of Ghana to evaluate integrated soil nutrient management approach on soil and yam productivity. A split-factorial design with two preceding systems (Pigeon pea and Yam) as main plot treatments and a factorial of poultry manure (0, 3 and 6 t ha-1) and chemical fertilizer (0, 15 - 15 - 20, and 30 - 30 - 40 kg ha-1 N-P2O5-K2O) as subplot treatments. The results of the study revealed significant (P < 0.05) interaction between preceding system, poultry manure and chemical fertilizer on fresh tuber yields. When yam followed pigeon pea as preceding crop, tuber yields were higher, and yields from 3 t ha-1 poultry manure and 15 - 15 - 20 kg ha-1 N-P2O5-K2O were similar to yields when manure and chemical fertilizer were doubled to 6 t ha-1 and 30-30-40 kg ha-1 N-P2O5-K2O. Also when yam followed pigeon pea, the cost benefit ratio showed that Gh 1.00 farmer investment in yam production resulted a profit of Gh 1.65 and Gh 2.22 in addition to the Gh 1.00 invested capital for both Fumesua and Ejura communities respectively. The study suggests integrated nutrient management approach with preceding systems such as pigeon pea (16,667 plants ha-1) and 3 t ha-1 poultry manure would reduce the chemical fertilizer requirement to a third for sustainable yam production on continuously cropped fields.Key words : Integration, legumes, climate change, Ghana