Assessment of Soil Fertility of Morogoro District, and Response of Maize (Zea mays) to Applied Nitrogen, Phosphorus and Sulphur

Abstract

Information on soil fertility is very important on application of fertilizers as plant nutrients supplement to correct Nitrogen, phosphorus and Sulphur deficiencies. The study objective was to evaluate the current fertility status of soils of Morogoro District and the response of maize to applied Nitrogen, Phosphorus and sulphur. Two field experiments were carried out in a season 2015/2016. Eighteen maize growing areas were selected, top soils, composite samples from a depth of 0-20 cm was collected and analyzed for physical and chemical properties as per standard procedures in the laboratory. Soil analysis laboratory results used as a means for soil fertility rating. Two of those sites classified as Ultisols (Kiziwa), and Inceptisols (Fulwe) with phosphorus (P), nitrogen (N) and sulphur (S) variability were used for field experiments. Treatments for field experiment were varied fertilizer levels, namely 0, 50, 100 kg N ha-1, 0, 10, 20 kg Pha-1 and 0, 10, 20 kg S ha-1. Absolute control treatment was included in both experimental site and the experiments was arranged in a completely randomized block design with three replicates at both sites. Results showed that studied soils had low soil fertility with slightly acidic to neutral pH in water (6.6-7.5), Low organic carbon (0.7-1.3%), low to very low total N (<0.01) and low extractable S (<3 mg/kg). 28% of studied soils had very high concentaration of P, low to very low CEC, very high exchangeable Ca2+, Mg2+ very low Na+ and adequate Concentration of K with micronutrients not limiting. Grain yield was significantly increased with application of N, P and S at (P=.05). Therefore a tentative nutrient combination of 50-100 kg N ha-1, 10-20 kg P ha-1, and 10-20 kg S ha-1 may be the best strategy for improving maize yields in Morogoro District while monitoring P Concentration with time.