耕作措施对三峡库区土壤侵蚀和养分流失的影响

Effects of Farming Practices on Soil Erosion and Nutrient Loss in the Three-George Reservoir Area.

为研究三峡库区土地耕作措施对土壤侵蚀和营养物质流失的影响,在三峡库区张家冲小流域设置10个不同土地利用方式的试验小区,在自然降雨条件下,进行为期1 a的小区试验,研究不同土地利用方式下土壤侵蚀和径流中氮、磷流失特征。结果表明:在10个试验小区中,土坎梯种柑小区年均径流量和土壤侵蚀量最大,土坎篱种柑小区年均径流量最小,坡地种粮小区土壤侵蚀量最小;坡篱种粮小区总氮和总磷年流失量最大,坡地种柑小区年流失量最小;土壤侵蚀和营养物质流失主要发生在6—8月降雨集中的暴雨季节。在类似于研究区域的其他农业区域,适合于坡地种柑,而坡篱种粮和土坎梯种柑是不适合推广的种植方式。

Ten experimental plots different in land use were set up to study characteristics of soil erosion and nutrient loss under natural precipitation in Zhangjiachong Watershed. The experiment lasted one year. Results show that the maximum annual runoff and the maximum soil erosion occurred in the plot of orange orchard on a terraced slope and the minimum runoff did in the plot of orange orchard on terraces with hedgerows, and the minimum soil erosion in the plot of grain cropland on a slope. The plot of grain cropland on a slope with hedgerows was the highest in loss of total nitrogen and total phosphorous,which amounted to 23.29 and 1.02 kg·hm^-2, respectively, while the plot of orange orchard on a slope the least in loss of total nitrogen and total phosphorous,which amounted to 9.50 and 0.15 kg·hm^-2 ,respectively. It is,thus recommended that in agricultural watersheds similar to the studied one, it is advisable to grow orange in sloping fields, but the land use patterns of growing grain crops on slopes with hedgerows and oranges on terraces slopes are not appropriate to extrapolate.