Effects of Rainfall on Soil Erosion,Nitrogen and Phosphorus Loss from Sloping Cultivated Land in the Hilly Area of Central Sichuan
To study the effects of different rainfall intensities on soil erosion,nitrogen and phosphorus loss from sloping culti-vated land in the hilly area of central Sichuan,simulated rainfall was used to explore the characteristics of runoff and sediment yield,as well as the nitrogen and phosphorus loss characteristics in sloping cultivated land in the hilly area of central Sichuan under different rainfall intensities(30,50,70,and 90 mm/h)and 15° slope conditions.The results showed that with the in-crease of rainfall intensity,the discharge and sediment yield of surface runoff and soil flow increased significantly(P＜0.05),and the time to reach the equilibrium was significantly shortened(P＜0.05),and the time to reach the equilibrium of surface runoff was the shortest(5 min)when the rainfall intensity was 70 and 90 mm/h.At the end of runoff generation period,the contents of total nitrogen,nitrate nitrogen and ammonium nitrogen in surface runoff and soil flow under rainfall intensities of 70 and 90 mm/h were significantly higher than those of 30 and 50 mm/h(P＜0.05).The contents of total phosphorus and soluble phosphorus in surface runoff and soil midstream showed a decreasing trend with the increase of rainfall intensity.Correlation analysis showed that rainfall intensity was positively correlated with surface runoff,surface runoff yield,soil runoff and sediment yield,and negatively correlated with nitrogen and phosphorus content(P＜0.05).The high intensity rainfall will increase the risk of soil hydraulic erosion and nitrogen and phosphorus nutrient loss in sloping cultivated land in the hilly areas of central Sichuan,and the results can provide basic data for the prevention and control of soil erosion and agricultural non-point source pollution in sloping cultivated land in the hilly areas of central Sichuan.
rainfall intensityrunoffnitrogen and phosphorus losssloping cultivated landhilly area of central Sichuan
万方数据
维普
