Abstract:

The Three Gorges Reservoir Area was a national key water and soil conservation area in China,and the relationship between land use/cover change (LUCC) and soil erosion was a focus in the field of soil erosion control research.The benefit of water and soil conservation for Returning Farmland to Forest Project is important to ensure the security in the Three Gorges Reservoir Area.Based on the monitoring of soil erosion with different patterns of returning farmland to forest in the Three Gorges Reservoir Area,the different characteristics of soil erosion under rainfall conditions and influencing factors were analyzed.The results indicated that: (1) soil erosion in the Three Gorges Reservoir Area had been effectively controlled by returning farmland to forest.After returning farmland to forest,surface runoff decreased by 70% to 95%,sediment loss was reduced by 97% or more,with different patterns of returning farmland to forest.And the forest and bamboo forest showed the best effect of soil and water conservation.(2) Annual surface runoff with different patterns of returning farmland to forest was related to the rainfall with an exponential relationship,and it increased with increasing rainfall.Surface runoff with different land use type was not significantly related rainfall intensity,except farmland and chestnut forest.(3) Sediment with different land use type was not significantly related with rainfall and rainfall intensity.(4) Eighty percent of surface runoff,95% of sediment loss with different land use types occurred in the storms,and storm event had been the major factor influencing soil erosion with the different patterns of returning farmland to forest in the Three Gorges Reservoir Area.(5) Litter cover was a key factor controlling surface runoff,annual surface runoff with the different land use types decreased significantly with increasing the litter cover in the Three Gorges Reservoir Area