Field Performance of Soybean (Glycine max (L.) Merill) with Farmyard Manure and Inorganic P Fertilizers in the Sub-Humid Savanna of Nigeria

In this paper, field trials were conducted during the rainy seasons of 2009, 2010 and 2011 in Samaru in the northern Guinea Savanna zone of Nigeria to evaluate the response of soybean to separate and combined applications of farmyard manure (FYM) and mineral phosphorus fertilizers levels. Soybean varieties TGx 1448-2E and TGx 1019-2E were grown with three levels of FYM (0, 1 and 2 t/ha) and four levels of P (0, 13.2, 26.4 and 39.6 kg P/ha) in all possible factorial combinations laid out as a randomised complete block design, replicated four times. The result showed that both varieties were similar in grain yield and 1 t/ha of FYM or 26.4 kg P/ha produced similar grain yields above 2 t/ha. Regression equation across the years showed soybean responded optimally to P rates ranging from 15.9 to 39.7 kg P/ha for grain yields of 1950.2 to 2665.4 kg/ha depending on the fertility status of the soil.