降雨对江子河小流域不同农作物措施坡面产流产沙的影响

Effects of Rainfall on Slope Runoff and Sediment Yield Under Different Crop Measures in the Jiangzi River Minor Watershed

水土流失已成为我国主要的生态环境问题之一。基于安徽大别山区江子河小流域2012—2019年自然降雨径流泥沙观测资料,探讨雨型对不同农作物措施坡面产流产沙的影响,采用随机森林算法分析降雨因子与水沙之间的关系。结果表明,在不同场次降雨中,径流量、土壤流失量随降雨场次变化规律较一致,红薯措施产流量及土壤流失量较大,茶叶措施最小。降雨分为3类:A型降雨(低频率、长历时、大雨量、高雨强)、B型降雨(高频率、短历时、小雨量、低雨强)、C型降雨(较低频率、较长历时、中等雨量、较高雨强),对产流产沙的影响表现为A型>C型>B型。降雨量对产流的影响程度最高,土壤流失量受PI、PI 60及降雨量和I 30的影响,I 60对产流产沙的影响程度偏低,小于11%。各农作物措施小区的径流深和土壤流失量相关性显著且具有线性关系,土壤流失量的增速为红薯>桑树>茶叶>板栗>黄豆>油茶。研究结果可为坡面侵蚀预报模型的建立提供重要的理论依据,对安徽大别山区水土保持工作的开展和生态文明建设具有重要的理论价值和实践意义。

Soil and water loss has become one of the main ecological environmental problems in China.The observation data of natural rainfall,runoff and sediment in the Jiangzi River minor watershed from 2012 to 2019 were used to explore the influence of rainfall types on slope sediment yield and runoff under different crop measures.Random forest algorithm was used to obtain the relationships among rainfall factors,runoff and sediment yield.The results showed that the changes of runoff and soil loss were consistent with the rainfall.The runoff and soil loss under sweet potato were larger,and tea gave the smallest.The rainfall could be classified into three types:Type A was rainfall with low frequency,long duration,heavy rainfall and higher rainfall intensity,Type B with high frequency,short duration,small rainfall and low rainfall intensity,and Type C with lower frequency,longer duration,moderate rainfall,high rainfall intensity.The degree of influence on runoff and sediment yield was type A>type C>type B.Precipitation had the highest degree of influence on runoff.The soil loss was affected by PI,PI 60,P and I 30,and I 60 had a low degree of impact on runoff and sediment production,less than 11%.The runoff depth of each crop measure had a significant and linear correlation with soil loss,and the growth rate of soil loss was sweet potato>mulberry>tea>chestnut>soybean>oil tea.These results provided important theoretical basis for the establishment of slope erosion prediction model,and were of important theoretical value and practical significance for the soil and water conservation work and the construction of ecological civilization in the western Dabie mountains area of Anhui Province.