干湿交替处理对土壤抗冲性的影响试验研究

为了研究作物生长季内，土壤经过干湿交替过程后的抗冲性的变化，采用原状土冲刷法，对黄绵土、塿土、黑土、紫色土4种代表性土壤在不同干湿交替次数处理下的抗冲性进行了研究。结果表明：干湿交替处理对土壤抗冲性的影响程度与土壤种类有关；黄土性土壤固有的抗冲性较低，而且在干湿交替处理下，其抗冲性变化不显著，抗冲系数几乎始终在2.5 L·min/g以下；东北黑土、川中紫色土在干湿交替影响下，其抗冲性变化明显，抗冲系数能达到12.0 L·min/g至16.0 L·min/g以上。在冲刷过程中，土壤抗冲性在一定程度上有增加的趋势，除去测定装置的因素，土壤本身性质发挥了一定的作用，而这与土壤种类有很大关系。本研究的结论表明，在不同土壤条件下，作物生长季内的土壤抗冲性变化应区分为作物根系的影响及土壤自身沉降压实的作用，特别是对于自身的抗冲能力较强的土壤。对于黄土性土壤或其他抗冲性较弱的土壤，防止集中水流的冲刷是坡面防蚀的关键。

Effects of Dry-wet Alternation Treatment on Anti-scourability of Soil

In order to investigate the variation of anti-scourability of soil after dry-wet alternation processes in growing season, this study investigated the anti-scourability of four typical types of soil under different dry-wet alternation treatments using undisturbed soil scouring method. The results showed that the influence of drywet alternation on anti- scourability of soil was related with soil type. Loessial soils’anti- scourability was relatively lower and didn’t vary obviously after dry- wet alternation treatment. The coefficient of antiscourability of loessial soils practically remained below 2.5 L·min/g in all treatments. Black soil in northeast China and purple soil in central Sichuan presented had obvious variation of anti-scourability after dry-wet alternation treatment, and the coefficient of anti- scourability would increase above 12.0 L·min/g to 16.0 L·min/g. In the scouring process, the anti-scourability had an increasing trend which was related not only to the measuring device, but also to the nature of soil. For different soil types, the change of anti-scourability during growing season should be divided into influence from crop roots and soil itself, especially for soils that had high anti- scourability. For loessial soil or other soils with low anti- scourability, avoiding scouring of concentrated flow is the key for erosion control.