模拟降雨条件下草被覆盖对坡地水土养分流失的调控机制研究

目的]研究黄土坡面草被覆盖对拦蓄水沙及调控养分的作用,为黄土坡面治理提供科学依据。方法]通过模拟降雨试验,收集降雨过程中坡面的径流泥沙样品,采用数据对比与统计分析相结合的方法,分析在不同草被覆盖条件下坡面径流泥沙以及养分磷流失过程,探讨草被覆盖率和草被格局对坡面泥沙及养分流失的调控作用。结果]随着降雨历时的增加,径流呈平稳增长过程,泥沙、径流总磷、泥沙速效磷均呈波动变化过程;25%,50%,75%覆盖率坡面径流总磷和泥沙速效磷分别为裸坡流失量的66%,85%,80%和62%,47%,21%;草被格局对水沙养分调控作用的差异性表现为:泥沙径流泥沙速效磷径流总磷。结论]草被对径流总磷的调控作用不强,对泥沙速效磷的调控作用显著;草被格局对径流和径流总磷的调控作用有限,对泥沙与泥沙速效磷的调控作用显著。

Experimental Investigation of Effects of Grass Coverage on Soil Erosion and Nutrient Transportation Under Simulated Rainfall

Objective] The effects of grass coverage on the regulation of soil erosion and nutrient loss were investigated to provide ways for the treatment of soil erosion on loess slope.Methods] The data of runoff and sediment were collected under simulated rainfall experiments. Statistical analysis was used to investigate the processes of runoff, sediment and nutrient loss in the loess slope with different grass coverage. Different percentage and pattern of grass coverage were selected to analyze the regulation of runoff, sediment and nutrient loss.Results] With the increase of rainfall duration, the runoff increased correspondingly. However, sediment, runoff total phosphorus and sediment available phosphorus fluctuated. As compared with the ones on bare slope, the quantity of runoff total phosphorus on the slopes with 25%, 50% and 75% coverages were reduced 66%, 85%, 80%; sediment available phosphorus loss on those slopes were reduced 62%, 47%, 21%, respectively. The effects of grass pattern on the regulation of runoff, sediment and nutrient loss ranked as sediment > runoff > sediment available phosphorus > runoff phosphorus.Conclusion] The regulatory effects of grass coverage on sediment available phosphorus was better than that on runoff total phosphorus. The regulatory effects of grass pattern on sediment and sediment available phosphorus were better than the ones on runoff and runoff total phosphorus.