小麦秸秆长度、覆盖量对坡面产流产沙的影响

为定量研究小麦秸秆覆盖对坡面产沙产流过程及减水减沙效益的影响,采用室内人工模拟降雨试验,研究在降雨强度为90 mm/h时,不同秸秆长度和秸秆覆盖量下的坡面产流产沙特征和产流产沙过程规律,结果表明:(1)在相同秸秆长度下,随秸秆覆盖量增加,产流量产沙量极显著减少(p0.01)。相同覆盖量水平下随秸秆长度增加,产流量显著增加(p0.05),在4.5 t/hm~2覆盖量下产沙量极显著增加(p0.01)。(2)秸秆覆盖坡面的初始产流时间较裸露坡面延迟6.23倍,产流量平均下降19.5%,产沙量下降31.6%。覆盖措施通过保护土壤的结构有效抑制了细沟侵蚀过程向切沟侵蚀发展。产流产沙过程受秸秆长度和覆盖量的交互作用影响,交互效应对产流过程的影响更突出。(3)随覆盖量增加,减水减沙效益极显著增加(p0.01);随长度增加,减水减沙效益分别减少为17.26%,27.97%。不同覆盖条件下的坡面产流量、产沙量和减水、减沙效益均与秸秆长度、秸秆覆盖量呈二元线性关系。(4)在当前试验条件下,当秸秆长度为3～5 cm,覆盖量为4.5 t/hm~2时达到最优减水减沙效益。

Effects of Wheat Straw Length and Coverage on Runoff and Sediment Yield

An artificial rainfall simulation experiment was conducted at the intensity of 90 mm/h,under different straw lengths and different straw coverage to study the characteristics of runoff and sediment production on the slope and the regularity of runoff and sediment production process. In order to quantify the effects of different wheat straw lengths and mulches on the characteristics and process mechanisms of slope runoff and sediment yield,as well as the benefits of water and sediment reduction efficiency under different straw conditions. Results showed that: (1) Under the same straw length,with the increase of straw coverage,the yield and sediment yield decreased significantly (p<0.01). At the same coverage level,with the increase of straw length,the yield increased significantly (p<0.05),and the yield of sand increased significantly under the coverage of 4.5 t / hm² (p<0.01). (2) The initial runoff time of the straw-covered slope surface was 6.23 times longer than that of the bare slope surface,and the average production flow rate decreased by 19.5%,the sediment yield decreased by 31.6%. Covering measures effectively inhibited the trend of trench erosion to cut trench erosion by protecting the structure of the soil. The process of runoff and sediment production is affected by the interaction of straw length and mulch. The effect is more prominent on the process of runoff. (3) With the increase of coverage,the benefits of water and sediment reduction increased significantly (p<0.01); with the increase of length,the benefits of water and sediment reduction decreased to 17.26% and 27.97% respectively. The slope runoff yield,sediment yield,water reduction,and sand reduction benefits under the different covering conditions have a binary linear relationship with straw length and straw coverage. (4) Under the experimental conditions,when the straw length is 3 ~ 5 cm,with the amount of 4.5 t/hm²,the optimal water and sediment reduction benefits are achieved.