一种改进的黑土农田风蚀集沙仪
A revised wind erosion sampler on arable Mollisols in Northeast China
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摘要: 风蚀监测可反映风沙运动规律,集沙仪是风蚀监测的必备仪器,而以往研究大多在沙漠或沙地开展,较少涉及黑土农田。本研究基于BSNE(Big Spring Number Eight)集沙仪,将采沙盒底部阻风结构中的18目孔径筛网改进为逆向百叶窗式的阻风挡板,采用模拟试验对比分析BSNE集沙仪和改进后rBSNE(Revised Spring Number Eight)集沙仪的保沙和集沙能力,并将其应用于野外黑土农田风蚀监测。研究结果表明:与BSNE集沙仪相比,rBSNE集沙仪降低了小粒级颗粒的损失率,当风速低于20 m·s−1时,对< 0.25 mm粒径的土壤颗粒的损失率显著降低74.3% ~ 87.1%;当风速达到20 m·s−1时,对所有试验粒径的土壤颗粒的损失率显著降低46.9% ~ 74.3%。与BSNE集沙仪相比,rBSNE集沙仪有助于对小粒级颗粒的收集,当风速低于20 m·s−1时,对粒径为< 0.5 mm的集沙量显著增加了9.0% ~ 44.0%;当风速达到20 m·s−1时,对所有试验粒径的集沙量均显著增加7.3% ~ 34.4%。野外监测结果显示风蚀输沙量随高度增加呈指数函数递减趋势,说明rBSNE集沙仪可应用于黑土农田风蚀的监测。Abstract:
Wind erosion observation reflects the wind-blown sand movement pattern. Sand sampler is an essential instrument for wind erosion observation. However, most of the previous studies were carried out in desert or sandy land, and little information was involved in arable Mollisols. Therefore, based on the BSNE (Big Spring Number Eight) sand sampler, the 18-mesh aperture sieve in the wind blocking structure was changed into the louvered windshield baffle, which was located at the bottom of the sand box. The holding and collection capacity between BSNE and rBSNE (Revised Spring Number Eight) sand samplers was compared and analyzed by simulation experiments. The rBSNE sand sampler was then applied to the field wind erosion observation. The results showed that compared with BSNE sand sampler, rBSNE sand sampler decreased the loss rate of small soil particles. When the wind speed was lower than 20 m·s−1, the loss rate of <0.25 mm soil particles significantly decreased by 74.3% to 87.1%; and when the wind speed reached 20 m·s−1, the loss rate of all soil particles significantly decreased by 46.9% to 74.3%. In addition, compared with BSNE sand sampler, rBSNE sand sampler was beneficial for the collection of small soil particles. When the wind speed was lower than 20 m·s−1, the collection of wind erosion with <0.5 mm soil particles significantly increased by 9.0% to 44.0%; and when the wind speed reached 20 m·s−1, the collection of wind erosion with all soil particles significantly increased by 7.3% to 34.4%. Furthermore, wind erosion rate decreased exponentially with the increasing height during the wind erosion observation period. This indicates that the rBSNE sand sampler can be applied to the wind erosion observation on arable Mollisols in Northeast China.