[Soil and water loss from cultivated slope land derived from granite under different cropping systems in Three-Gorges reservoir areas].

The water and soil loss caused by cultivation on slope land derived from granite under different cropping systems in the Three-Gorges reservoir area was analyzed based on the data from localized observation. The results showed that in this area, proximately 60% of total annual rainfall, distributed in May to August, and 60% of soil erosion occurred in these four months, with 50% in June and July. The coverage rates under different cropping systems differed significantly, e.g., triple-cropping systems and inter-croping system with perennial plants (grass and day lily) had a bigger covering than double-cropping systems. The soil loss under cropping system with peanut was much lower than that with sweet potato, because the covering rate of the former was higher than that of the latter in summer raining season. The sequence of soil and nutrient loss for different cropping systems was rape (wheat) sweet potato > rape(wheat)/corn/sweet potato > rape(wheat)/corn/peanut/rape(wheat)/grass/peanut/rape(wheat)/day lily/peanut. It was concluded that soil loss from cultivated slope land could be controlled below a permissible value, if rational cropping and management systems were adopted.