Selecting 4 erosion factors of rainfall erosivity

soil erodibility

topography undulating degree

and vegetation coverage

this paper evaluated the effects of the returning farmland to forest project(RFFP)on the changes of soil erosion sensitivity with the aid of USLE and GIS.Results showed that mild sensitivity and moderate sensitivity were the main sensitivity types and their area proportions were 39.61% and 29.04% before the RFFP and 37.79% and 34.03% after the RFFP

respectively.In the south

non-sensitivity and mild sensitivity were the main sensitivity types and in the southwest

the non-sensitive area increased.In the north

the moderately

highly

and extremely sensitive types embedded each other before the RFFP

but the distribution pattern of them became obviously regular after the RFFP.Before the RFFP

soil erodibility played an important role in erosion sensitivity

while the role of rainfall erosivity was quite ordinary.After the RFFP

the effect of soil erodibility decreased sharply

while the rainfall erosivity increased quit obviously.In a word

the RFFP has improved soil erosion sensitivity.The need for soil and water conservation is still urgent in the highly and extremely sensitive regions.