Mathematical Modeling of Nutrient Release from Capsulated Fertilizers

The article is devoted to the study of reducing the technogenic load from high-dose nitrogen pollution of the soil layer by encapsulating granules of nitrogen fertilizers in slowly soluble phosphate-containing membranes. The process of dissolving and washing out of the primordial soil layer of the nutrients from urea, encapsulated by superphosphate shells in soil columns, was studied according to agrochemical techniques. The purpose of the work is to determine the parameters of the investigated process, based on which the previously developed physical model of soil washing of moving nitrogen forms, based on experimental data. The process of changing the loss of nitrogen from the soil when using different types of fertilizers depending on the amount of washing was studied by simulation. Mathematically, the process is described in general terms as a linear differential equation of the first order in partial derivatives. The solution of the equation under the initial and boundary conditions allowed to calculate the parameters of the model describing the nature of changes in the losses of nitrogen from the soil column. Comparison of calculated and experimental data showed a coincidence of values with a correlation coefficient above 0.96 for investigated nitrogen fertilizers with different composition of the phosphate-containing coating.