Effects of Cultivation and Vegetation Coverage on Soil Organic Carbon under Water Erosion in Regions of Hilly Purple Soil

摘要

The soil productive forces are mainly affected by soil erosion as soil nutrients and organic carbon are taken away. On the premise of analysis the last 17 years' data of cultivation and vegetation coverage in Xiejiawan small watershed. the relationships between the reduction of soil organic carbon and impact factors of soil erosion was investigated and analyzed. Results showed that transverse slope with ridge in a field contributed less to the losses of organic carbon of purple soil than slope farming, and even less than traditional farming under the condition of the same slope and rainfall. However, deeply digging of the bared land was easier to bring about loss of organic carbon of soil. And with the increase of vegetation cover. the loss of soil organic carbon reduced gradually. The vegetation coverage should be maintained at more than 66% if the loss of organic carbon of soil was to be controlled from the aspect of vegetation coverage. Thus, it is effective to control loss of soil organic carbon by increasing vegetation coverage unless there was more than 66% vegetation coverage, under the condition of water erosion.