Influences of the Grain-for-Green project on grain security in southern China

- The spatial pattern of soil erosion in southern China was modeled.
- Most cropland in southern China experiences no obvious or moderate soil loss.
- Grain-for-Green project would not damage grain security in southern China.
- Governments should continue the Grain-for-Green project based on both slope and soil erosion degrees.

Ensuring grain security has always been a top priority in China. As one of the major grain production areas in China, southern China is currently being criticized for the urban encroachment on prime agricultural land and decrease in grain production due to Grain-for-Green project. Based on the erosion pattern from the RUSLE model, spatial analysis is performed to analyze the possible loss of grain production if cropland under different degrees of soil erosion is exposed to the Grain-for-Green project. The projected total grain production on the basis of the 2000 grain production data in south China will decrease by 7.77% if cultivation is stopped on the cropland with high, very high, severe and very severe erosion, which, although not affects the grain security in southern China, would damage the grain security for the whole China. However, if all cropland on slopes above 25° is converted to forest or grassland, grain production will decrease by 2.1%. If all cropland covered with high, very high, severe and very severe erosion on slopes above 25° is converted to forest or grassland, grain production will decrease by 0.91%. Neither of the two measures will damage grain security in southern China, nor the whole China. So, the government should continue the Grain-for-Green project based on both slope and soil erosion degrees to ensure the grain security and reduce soil erosion at the same time.