Land-use change from arable lands to orchards reduced soil erosion and increased nutrient loss in a small catchment.

China has been undergoing dramatic land-use change since the1980s. More arable lands have been converted to orchards to produce high-value fruits. There is an urgent need to assess the effects of these land-use changes on soil erosion and nutrient loss in the country. In this study, the Revised Universal Soil Loss Equation model, geographical information systems, and, remote sensing data were used to evaluate the effects of land-use change on soil erosion and nutrient loss in the Yujiahe Catchment, where a significant portion of the arable land that grew wheat and maize between1957 and 1989 was converted to kiwifruit orchards between 1990 and 2013. The total soil erosion from the catchment during 1957-2013 was in line with the sediments in the reservoir at the catchment outlet. Arable land was the major source of soil erosion and its erosion intensity was approximately ten times that of the orchards. The land-use change from arable land to orchard land since 1990 has reduced soil erosion intensity from severe to moderate. The arable land covering 28% of the catchment contributed to 81.3% of total organic matter loss and 80.4% of total nitrogen loss. However, the loss of available phosphorus mainly occurred in the orchards, representing 66.7% of the available phosphorus loss in the catchment. The soil erosion intensity of the arable land was highly sensitive to the land slope. We concluded that land use change from arable land to orchard land reduced soil erosion and increased the risk of nutrient loss from the catchment.