秸秆覆盖和有机质输入对紫色土土壤可蚀性的影响

以紫色土坡耕地为研究对象开展野外径流小区定位监测试验,设置有机质(OM)、秸秆覆盖(SW)、有机质+秸秆覆盖(OM+SW)和对照(无秸秆覆盖,不增施有机质,CK)4个处理,对2014年侵蚀性降雨条件下不同处理小区径流及产沙特征进行分析,以单位径流冲刷侵蚀量(K_w)作为土壤可蚀性指标,研究四川省中江县紫色土区秸秆覆盖和有机质输入对坡耕地土壤可蚀性的影响。结果表明:秸秆和有机质输入能显著降低紫色土区坡耕地产流量,4个处理减小径流的效果表现为OM+SWSWOMCK;有机质、秸秆覆盖均显著降低单位径流侵蚀量,从而减小土壤可蚀性,OM、SW、OM+SW处理对土壤可蚀性的平均消减率分别为22.30%、29.76%、35.04%,秸秆覆盖处理(SW)对土壤可蚀性的减小效应略高于有机质处理(OM),但二者差异不显著。综合分析得出,增施有机质的同时进行秸秆覆盖可作为紫色土区坡耕地减小土壤可蚀性的有效措施。

Combined Effects of Straw Mulch Cover & Organic Matter Input on the Erodibility of Purple Soil in Sloping Farmland

Based on the data from rainfall and field runoff plots in 2014, a field experiment was conducted in Sichuan to evaluate the runoff, sediment characteristics and soil erodibility of purple soil on the sloping farmland soil as affected by the straw mulch cover and organic matter input. There were four treatments as organic matter input (OM), straw mulch (SW), combined treatment of organic matter input with straw mulch treatment (OM+SW), and control group(CK). The sediment yield in unit area runoff plots by unit individual runoff depth (Kw) was used to describe the soil erodibility. The results showed that there was a positive linear correlation between runoff depth and sediment yield. More importantly, straw mulch and organic matter input can significantly reduce surface runoff in sloping farmland. Besides, the effects of four treatments in reducing surface runoff was ranked as: OM+SW>SW>OM>CK. Straw mulch and organic matter input can notably decrease unit sediment yields caused by runoff and thus reduce soil erodibility. The contribution of organic matter treatment (OM), straw mulch treatment(SW) and organic matter+straw mulch(OM+SW) treatment on the reduction to soil erodibility were on average 22.30%, 29.76% and 35.04%, separately. Additionally, the subtractive effects of straw mulch treatment (SW) on soil erodibility were more obvious than organic input treatment (OM), but the differences were not significant. Therefore, it is suggested to use organic matter input together with straw mulch as a practical tillage way to eliminate soil erodibility for this region.