Effect of Integrated Application of Soil Amendments on Nutrient Uptake and Soil Properties in a Tropical Alfisol

A field experiment was conducted on a tropical alfisol for two consecutive years to determine the effect of integrated application of nutrient sources on nutrient uptake and soil properties. The treatments consisted of two rates of poultry manure (0 and 5 t ha-1 ), three rates of N fertilizer (0, 50 and 100 kg N ha-1 applied as urea), three rates of P fertilizer (0, 30 and 60 kg P ha-1 applied as single superphosphate) and two soybean treatments (with or without legume residue) arranged as a factorial experiment using Randomized Complete Block Design (RCBD) with three replicates. Soil samples were collected, processed and analyzed for soil nutrients and properties before planting and after harvests. Results showed that combined application of manure and N fertilizer had greater impact on soil organic matter build up than the separate inputs when singly applied. Results also revealed manure and N fertilizer to be the major factors that controlled plant uptake of N throughout the study. Legume, throughout the experiment was not found to be an important factor in plant uptake of N and P. CEC values were observed to be generally slightly higher in the second year of the experiments indicating a positive effect of integrated application of the soil amendments on soil properties.