Response of yield and nutrient (nitrogen and phosphorus) loss to changes of fertilizer amount across agricultural lands over China

Abstract:

Fertilizer application on agricultural land has been a major contributor to non-point source pollution and degradation of water quality across China. This study aimed at quantifying the changes of yield and nutrient loss due to changes of fertilizer amount. The mainland China was subdivided to 0.5 mins grid, those of which contains agricultural land were picked (totally 41911 grid were selected). Over each grid, the soil, land use, climate data, management practices were prepared and formatted into the Agricultural Policy Environmental Extender (APEX) model. Then, 21 fertilizer levels (0 to 200 kg/ha with 10 kg/ha increment) for 9 major economic crops (rice, maize, soybean, wheat, cotton, groundnut, sugarcane, sugarbeet, rapeseed) were simulated. The responses of yield and nutrient loss were extracted from each grid, and a distribution of the response were generated based on the results. The results of this study will help testify the hypothesis that reduction of fertilizer application will not significantly reduce yield but significantly reduce nutrient loss from agricultural fields.