阴山北麓农牧交错区保护性耕作带地表抗风蚀能力的测试与分析

Testing analysis on anti-erosion capability of conservation tillage strip surface in agro-pastoral mixed regions of Yinshan Mountain

【目的】揭示农牧交错区带状间作农田土壤的抗风蚀效应,为防治农田土壤风蚀提供理论依据和技术指导。【方法】以阴山北麓农牧交错区保护性耕作农田的土壤为研究对象,利用移动式风洞和与之配套的风速、集沙仪测试设备,对3种残茬覆盖地表(小麦留茬,65%盖度,20cm茬高;小麦留茬,76%盖度,30cm茬高;莜麦留茬,90%盖度,30cm茬高)在给定的5个风速(6,9,12,15和18m/s)等级下,其地表的空气动力学粗糙度和风蚀量随测点距离风洞试验段进口位置(模拟保护性耕作带宽度)的增加(3,3.75,4.5,5.25和6m)所呈现的变化规律进行分析。【结果】随测点距风洞试验段进口距离的增加,3种地表在不同风速下的空气动力学粗糙度均呈先增大后减小的趋势,大多于该距离为5.25m时达最大值;不同风速下的风蚀量则随测点距风洞试验段进口距离的增加呈快速下降趋势,在该距离达到5.25m之后,风蚀量的下降趋于平缓。【结论】残茬高度与植被盖度可明显增强地表的抗风蚀能力,当保护性耕作带的宽度达到5.25m以后,其抗风蚀效果更加稳定和显著。

【Objective】 The paper uncovered the wheat and potato strip intercropping farmland＇s resistance effects to wind erosion in the agro-pastoral ectone in order to provide theoretical foundation and techonological direction.【Method】 Based on agro-pastoral mixed areas of Yinshan Mountain in Inner Mongolia,soil-erosion testing experiments were conducted on three stubble coverage farmland（wheat stubble coverage,coverage 65% and 76%,stubble height 20 cm and 30 cm;naked oats stubble coverage,coverage 90%,stubble height 30 cm） under 5 scheduled velocities（6,9,12,15 and 18 m/s） by means of the movable wind tunnel and its suited velocity and sand sampling eguipments.The author analyzed the change disciplinarian of the surfaces＇aerodynamic roughness and wind erosion amount with the increasing distance of tested points（3,3.75,4.5,5.25 and 6 m） from wind tunnel experiment section entrance（Simulating conservation tillage farmland＇s stubble widthes）.【Result】 The roughness of three kinds of surface showed early increasing and subsequent decreasing trend with the increasing distance of tested points from wind tunnel experiment section entrance under different velocities and the majority reached the max when the distance was 5.25 m;The wind erosion amount revealed rapid decreasing trend with the increasing distance of tested points from wind tunnel experiment section entrance under different velocities,the decreasing trend of wind erosion amount was gentle when the distance reached 5.25 m.【Conclusion】 Conservation tillage farmland＇s stubble height and vegetation coverage increase anti-wind erosion significantly.Anti-wind erosion effect of conservation tillage farmland tends to be more steady and significant when conservation tillage farmland effective width reaches 5.25 m.