Mathematical Model of Solute Transport from Soil to Runoff in Different Rainfall Patterns and Polyacrylamide Applications.

Nutrient losses with soil erosion are a major cause of soil degradation and agricultural non-point source pollution. Rainfall patterns and polyacrylamide applications have a significant influence on the process of sediment yield and nutrient loss. The mathematical models developed in this study were used to simulate the sediment and nutrient loss in surface runoff. A simulation experiment was conducted to investigate the effects of rainfall patterns (3 raindrop diameters of 2.67, 3.15 and 3.79 mm) and polyacrylamide application rates (0 and 2 g m^-2) on soil losses and the concentration of ammonium nitrogen and phosphate in runoff. The results revealed that changes in the rainfall pattern can have an appreciable impact on the process of runoff, but only a slight effect on the total amount of runoff. The runoff, sediment rates and nutrients losses were decreased with polyacrylamide applications. Significant effect on the process of sediment yield and nutrient loss with different rainfall patterns, and the big raindrop diameter may lead to the most severe erosion and nutrient loss. In this study, the calculated data concur with the measured values. The model can be used to predict the process of sediment transport and nutrient loss associated with different rainfall patterns and polyacrylamide applications.