Mineralization Rates of Soil Forms of Nitrogen, Phosphorus, and Potassium as Affected by Organomineral Fertilizer in Sandy Loam

Abstract

Farmers tend to use organomineral fertilizers as a result of inadequacies embedded in the sole use of organic and mineral fertilizers. A laboratory incubation study to determine the rate of the forms of N, P, and K released by organomineral fertilizer was conducted at Adeyemi College of Education, Ondo, southwest Nigeria, in 2013. Organomineral fertilizer (OMF) at the rates of 0, 0.125, 0.25, 0.5, and 1.0 g/100 g soil to represent 0, 2.5, 5, 10, and 20 t ha-1 OMF, respectively, was incubated for ninety days. The treatments were replicated three times and arranged in a completely randomized design. The determined forms of N were total N, NH4-N, and NO3-N; the forms of P were total P, solution P, and available P while the forms of K were total K, solution K, and exchangeable K. Organomineral fertilizer significantly increased N, NH4-N, NO3-N, total P, solution P, exchangeable P, solution K, and exchangeable K at all rates with different values. The rate of ammonification of N was higher than the rate of nitrification of NH4 + N to NO3 + N especially at 10 and 20 t ha-1 OMF. Application of 5 and 10 t ha-1 OMF could be used to increase soil forms of N, P, and K.