[Characteristics of Nitrogen and Phosphorus Output in Runoff and Rainfall Runoff in Lanlingxi Watershed, Three Gorges Reservoir Area].

lost by ammonium nitrogen and total phosphorus; ②The distribution of rainfall has the characteristics of stage and strong rainfall during the wet season was the main driving force of soil nutrient output. Rainfall runoff contributed to 88% of total nitrogen loss and 90% of total phosphorus loss in the rainy season; ③The main path of nitrogen and phosphorus loss in the rainy season was the surface runoff caused by rainfall, accounting for 68% of total nitrogen loss and 74% of total phosphorus loss; ④Nitrate nitrogen concentrations showed a negative correlation with rainfall runoff and the output was mainly distributed in the later runoff process. Ammonium nitrogen and total phosphorus concentrations were positively correlated with rainfall and both were mainly distributed in the early stage of the runoff process; ⑤The concentrations of total nitrogen in this watershed exceeded the standard values. The water quality in the rainfall and the non-rainfall period was worse than Grade Ⅴ.