[Effects of near-surface soil water conditions on agricultural non-point source pollutant transport]

Agricultural non-point source pollution is one of severe problems for water environment of agricultural area in China. The effects of near-surface soil water conditions on agricultural non-point source pollutant (AGNSP) transport during soil erosion processes, especially antecedent soil moisture was saturated, was developed by using artificial simulation rainfall experiment. The results showed that antecedent soil water content had great impact on AGNSP transport during soil erosive processes. Under the same soil texture, the AGNSP concentration and loading with runoff and sediment when the antecedent soil water content was saturated were greater than that of soil moisture un-saturated condition, and they would be increased as antecedent soil moisture increased. The approach of soil nitrogen loss was rainfall runoff; nitrogen loss with runoff was about 90.4% to 99.8% of total loss. The approaches of soil phosphorus were runoff and soil loss (sediment), the loss with runoff was about 2.67% to 23.5%, and the loss with sediment was about 76.5% to 97.3%. Soil texture had great influence on soil phosphorus loss; the concentration and loading of dissolved phosphorus (DP) with sediment from Yangling Loutu were greater than that of Ansai Loess. Some pertinence suggestions were given to control agricultural non-point source pollution, such as the best management practices.