不同秸秆移除条件下冻融对农田土壤风蚀可蚀性的影响

为研究实际生产中不同秸秆移除率条件下冻融作用对土壤风蚀指标的影响，2011—2013年在美国堪萨斯州3个县设置3个不同秸秆移除率:0，50%，100%，对春秋季节土壤侵蚀比（EF）、平均几何直径（GMD）、地表随机粗糙度（RR）进行了统计分析。结果表明:（1）在冻融作用下，秸秆留茬能够有效减轻土壤风蚀，随着秸秆移除率的增大，土壤EF值增大，GMD值、RR值减小；（2）经过2011—2012年的冻融作用，2012年春季Norcatur、Colby、Scott City三地秸秆100%移除组的EF值增幅分别为149%，185%，16%，50%移除组的EF值增幅分别为40%，152%，-28%，0移除组的EF值增幅分别为29%，47%，9%；（3）休耕对于增强土壤抗风蚀能力有一定积极作用。研究成果为我国易发生土壤风蚀季节性冻融地区的适宜秸秆移除率的研究提供参考。

Freezing and Thawing Impacts Agricultural Erodibility Under Varied Straw Cover

In order to examine the effect of freeze-thaw on soil erosion at different crop straw removal rates, three different removal rates at 0, 50%, 100% were set in three experimental sites in Kansas from 2011 to 2013. Measured parameters include erodible fraction (EF; aggregates<0.84 mm), geometric mean diameter (GMD) and random roughness (RR). The results showed that straw stubble could effectively reduce wind erosion under the effects of freezing and thawing; the EF value of soil increased and the GMD value and RR value decreased with the increase of the removal rate of straw; After freezing and thawing in 2011—2012, the increase rates of EF were 149%，185%，16% under the treatment of the 100% removal in Norcatur， Colby and Scott City， respectively, 40%， 152%，-28% under the treatment of the 50% removal, and 29%， 47%， 9% under the treatment of 0 removal; fallow has the positive effect on enhancing the ability of soil to resist wind erosion. These results have certain reference values for the research on suitable straw removal rate in the seasonal freezing and thawing area which is prone to soil erosion in China.