三峡库区花岗岩坡耕地不同种植方式下水土流失定位研究

对三峡库区花岗岩坡耕地不同种植方式下水土流失规律的定位研究表明,库区雨季主要集中在5～8月,降雨量约占全年总降雨量的60%以上;此期间的土壤侵蚀量也占全年总侵蚀量的60%以上,其中6、7月土壤侵蚀量约占全年的1/2.不同种植方式下地面覆盖率差异较大,三熟制下或与多年生植物(牧草、黄花菜)间作时地面的覆盖率明显大于两熟制,夏季作物为花生时雨季的地面覆盖高于夏作为红薯,其土壤及养分流失量亦相对较低.不同种植方式下土壤及养分流失的大小顺序为油(麦)红薯>油菜(小麦)玉米红薯>油菜(小麦)玉米花生>油菜(小麦)金荞麦花生,油菜(小麦)黄花花生.研究结果还表明,在良好的种植与管理方式下,坡耕地土壤流失量仍可被控制在允许范围内.

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 monthes,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.