人工降雨条件下秸秆覆盖及留茬的水土保持效应

通过人工模拟降雨试验,研究了秸秆覆盖及留茬的水土保持效应。结果表明,秸秆覆盖和留茬均可延缓径流产生,其中5 000和3 000 kg/hm2秸秆覆盖分别能使初始产流时间延后427%和19%,而30 cm高留茬及15 cm低留茬覆盖则可分别延后初始产流时间107%和76%。5 000 kg/hm2覆盖量下累积径流量较对照减少了61.72%,土壤侵蚀量减少了86.7%;3 000 kg/hm2覆盖量下累积径流量减少了6.26%,土壤侵蚀量减少了60.1%,实施覆盖能够有效抑制水土流失,且以高覆盖量的作用效果更为显著。30 cm高留茬的土壤侵蚀量较对照减少了62.9%,15 cm低留茬覆盖减少25.6%,留茬能够有效防止土壤侵蚀,但对径流量无明显影响。

Effects of Straw Mulch and Stubble on Soil and Water Conservation Under Stimulated Rainfalls

A number of experiments with artificially simulated rainfalls were conducted to study the effects of straw mulch and stubble on soil and water conservation.The results show that both straw mulch and stubble delayed the runoff initiating time,by 427% and 19% for the treatments with straw mulch applications of 5 000 and 3 000 kg/hm2,and by 107% and 76% for the treatments with 30 cm high stubble and the combination of 15 cm low stubble and straw mulch,respectively.Compared with the control,the cumulative amount of runoff and sediment was reduced by 61.72% and 86.7% in the treatment with straw mulch application of 5 000 kg/hm2,and by 6.26% and 60.1% with straw mulch application of 3 000 kg/hm2,respectively.Straw mulch,especially with high application rates,could effectively control soil water erosion.In contrast,30 cm high stubble reduced soil erosion by 62.9% and 15 cm low stubble by 25.6%.Both of the stubble treatment could effectively reduce the soil erosion,but showed no significant effect on surface runoff.