Variations of Runoff and Soil Erosion in Agroforestry Watersheds in Funiu Mountains

Based on GIS technology and AnnAGNPS model,the outputs of runoff and soil erosion in different periods of seven typical agroforestry watersheds in Funiu Mountains were studied.The results showed that after the implementation of the project of returning farmland to forests and ecological industrialization in the study watersheds in the Funiu Mountains,the function of soil and water conservation has been continuously enhanced.Compared with 2000,in 2020,the average surface runoff of the seven watersheds decreased by 40.7 mm,and the soil erosion amount decreased by 5.41 t/hm;the watershed runoff had a significant positive correlation with slope (P < 0.05),a significant negative correlation with forest land area ratio (P < 0.05),but no significant correlation with agricultural land ratio;soil erosion was negatively correlated with forest land (P < 0.05),but positively correlated with farmland (P < 0.05);and the average spatial variation coefficient of soil erosion was 160%,which was 4.35 times that of runoff,and the uncertainty of factors affecting soil erosion was much higher than that of runoff.