【摘要】 三峡库区紫色土坡地的模拟降雨实验表明 ,香根草 (Vetiverzizanioides)等高植物篱—农作系统能有效地控制坡面土壤侵蚀。单纯等高植物篱处理小区的侵蚀量仅为在相近雨强及雨量条件下对照坡耕地的 37 71%。植物篱截短坡长 ,防止细沟侵蚀产生和发展是侵蚀量明显减少的一个主要原因。等高植物篱—农作系统带间覆盖和施用有机或无机肥能进一步将小区侵蚀量减少至对照坡耕地的 0 18%～ 0 19%。植物篱能有效拦截流失的土壤大颗粒 ,使侵蚀泥沙中粒径 <0 0 2mm的细粒比例增加 ,多数养分有明显富集。土壤细颗粒的损失对土壤有效钾影响最大。植物篱—农作系统建成初期和单纯农作系统氮、磷养分流失途径以侵蚀泥沙的携带为主。植物篱完全蔽合 ,篱前淤积带形成后 ,由于植物篱和覆盖物的阻滞 ,径流与土壤的更充分分作用 ,使植物篱—农作系统的径流中钾含量提高 ,径流成为有效钾损失的主要途径更多还原

【Abstract】 The simulated rainfall in the Three-Gorge-Reservoir region indicated, the Vetiver zizanioides contour hedgerow-crop system are more effectively in reducing soil loss than pure crop system on the purple slopeland. Soil loss of the pure contour hedgerow plot was 37.71% of that of the pure crop plot. The reduction of soil loss by hedgerows was mainly because the slope length cutting down which can avoid rill erosion. Coverage and fertilization in the contour hedgerow-crop system could reduce soil loss to 0.18%-0.19% of that of the pure crop plot. The hedgerows could intercept coarse particle, therefore, the <0.02mm particles enriched in the sediment, and most nutrients enriched too. The loss of fine soil has the most sensitive impact on available potassium.According to the pure crop system and initial contour hedgerow-crop system, the major way of nitrogen and phosphorus loss was in sediment loss. However, because of the interception to runoff by hedgerows and coverage, the further interaction between soil and runoff could increase the content of potassium in runoff, and the potassium loss in runoff became the major way of available potassium loss.更多还原