Prediction of nitrogen transformations in alkaline soils.

Abstract

A digital computer program was developed which models soil-water systems with respect to nitrogen transformations, including hydrolysis of urea, immobilization-mineralization of ammonia and organic nitrogen, and immobilization of nitrate nitrogen. Transformation rate equations were derived by applying techniques of systems and statistical analysis and using selected data from the literature. Simultaneous integration of the equations over time generates predicted concentrations for urea-N, organic-N, ammonia-N, and nitrate-N in the system. Comparisons were made of predicted and observed data for several soils having different textures and various moisture contents, temperatures, and fertilizer applications. This procedure yielded simple correlation coefficients of 0.992, 0.768, 0.969, and 0.972 for the previously mentioned nitrogenous types, respectively.