Spatial and Temporal Heterogeneity Study of Agricultural Non-Point Source Pollutant Loading of Zhangxi Watershed

The AnnAGNPS model (Annualized Non-Point Source Pollution Model) is applied to analyze the spatial and temporal heterogeneity of agricultural non-point source pollutant loading in Zhangxi Watershed. The spatial database and attribute database of non-point source pollution is then established. Our result shows that in spatial scale, absorbed nitrogen has great spatial heterogeneity, while dissolved phosphorus´s heterogeneity is relatively small. The pollutant loading in orchard and woodland is smaller than that in farmland; paddy soil´s is larger compared to those in yellow and red soil. In temporal scale, over 55% of the pollutant loading happens in flood season. There is only 4% in dry season.