模拟降雨条件下林下枯落物层减流减沙效应  

Effects of undergrowth litter layer on runoff and sediment reduction under simulated rainfall conditions

作　　者：常玉[1] 余新晓[1] 陈丽华[1] 樊登星[1] 梁洪儒 孙佳美[1] 

机构地区：[1]北京林业大学水土保持学院

出　　处：《北京林业大学学报》2014年第3期69-74,共6页Journal of Beijing Forestry University

基　　金：林业公益性行业科研专项(20130430104);教育部博士点基金项目(20090014110002)

摘　　要：通过室内模拟降雨试验，研究了不同坡度、雨强条件下枯落物覆盖对坡面产流过程和侵蚀过程的影响。结果表明：1）枯落物单位面积生物量越大，坡面产流越迟，并且枯落物覆盖延迟地表径流产生的作用在30mm／h雨强下较60mm／h更为突出；2）坡面总径流量随枯落物单位面积生物量增大而减小，30mm／h雨强下减少率在4．8％-54．8％之间，60mm／h雨强下减少率在4．2％～26．8％之间，30mm／h雨强下枯落物的减流效应要优于60mm／h雨强；3）坡面产沙率和总产沙量均随枯落物单位面积生物量的增大而减小，当枯落物生物量为50g时，坡面的总产沙量相比裸坡可降低56．2％-68．0％，枯落物生物量达到200g之后坡面总产沙量相比裸坡能降低92．2％以上，即使在60mm／h雨强下枯落物层仍能发挥良好的减沙效果；4）枯落物层拦截泥沙的效应要强于其减少径流的效应，有枯落物覆盖的坡面，在径流量较大的情况下，产沙量也可能较小。实验表明，要发挥枯落物层良好的水土保持功能，枯落物单位面积生物量需达到250g以上。The indoor simulated rainfall experiment was used to quantify the effects of litter coverage on runoff and soil erosion processes under different slope gradients and rainfall intensity conditions. The main results were as the followings： 1 ） the more the litter biomass in unit area was, the later the slope initial runoff generated. Besides, the effect of litter coverage on putting off runoff generation was better under 30 mm/hour rainfall intensity than 60 mm/hour. 2） Slope total runoff decreased with litter biomass in unit area increased. Compared with bare slope, the total runoff under rainfall intensities of 30 and 60 mm/hour decreased by 4.8%- 54.8% , 4.2%- 26.8% , respectively. Obviously, the effect of litter reducing runoff was better under 30 mm/hour rainfall intensity than 60 mm/hour. 3） Both slope sediment yield rate and total sediment yield decreased with litter biomass in unit area increased. Compared with bare slope, the total sediment yield could decrease by 56.2% -68.0% when the litter biomass in unit area was 50 g, while, when the litter biomass in unit area reached 200 g, the total sediment yield could drop over 92.2%. In particular, litter layer could still play an important role in sediment reduction when the rainfall intensity was 60 mm/hour. 4） Litter layer has a better effect on reducing sediment than reducing runoff. On the slope with litter coverage, the sediment yield maybe quite little when the runoff was rich. Experiment showed that to take full advantage of litter layer in soil and water conservation function, litter biomass in unit area had to reach more than 250 g.

关 键 词：人工模拟降雨 枯落物 径流量 产沙量 产流时间 

分 类 号：S714.7[农业科学—林学]