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为了探讨直立作物残茬防治农田土壤风蚀发生的机理,该文利用风洞试验和野外观测相结合的方法,分析土壤免耕条件下直立作物残茬对农田土壤风蚀的影响。风洞试验研究表明:翻耕土壤地表风速、土壤风蚀侵蚀率均比免耕土壤高,而地表粗糙度免耕明显高于翻耕。在同样风速条件下,翻耕地土壤风蚀侵蚀率是免耕地的3～8.2倍,且随免耕年限的增加,土壤风蚀侵蚀率呈现递减的趋势。留有不同直立作物残茬免耕土壤地表粗糙度草谷子>草玉米>莜麦>油菜,土壤风蚀侵蚀率呈现相反的趋势,地表粗糙度越大,风蚀侵蚀率越小。野外观测结果表明,不同直立作物残茬对裸露农田的保护作用草谷子>莜麦>草玉米>油菜。风洞试验与野外观测具有相似的试验结论,因此,风洞试验方法可作为测定农田土壤抗风蚀能力的重要工具。
In order to investigate the mechanism of crop stubborn soil erosion control by erect crop, this paper analyzed the effect of standing stubble on wind erosion of farmland soil under the condition of no-tillage with wind tunnel test and field observation. Wind tunnel test results show that the surface wind speed and soil erosion rate of tilled soil are higher than that of no-tillage soil, while the surface roughness of no-tillage is obviously higher than tillage. Under the same wind speed, the soil erosion rate of tillage land is 3 ~ 8.2 times of that of no-tillage land. With the increase of no-tillage time, the erosion rate of soil wind erosion shows a decreasing trend. Leaves with different vertical crop stubble no-tillage soil surface roughness grass millet> grass corn> oat> rape, the soil erosion rate showed the opposite trend, the greater the surface roughness, the smaller the erosion rate. Field observations showed that the protective effect of stubble on the exposed farmland was different from that of the control. Wind tunnel test and field observation have similar experimental conclusions. Therefore, wind tunnel test method can be used as an important tool to determine wind erosion resistance of farmland soil.