白三叶不同部位减沙效应及其对径流水动力学参数的影响

发布时间：2018-05-20 11:47

本文选题：坡面侵蚀 + 水力学参数　；参考：《生态环境学报》2016年08期

【摘要】：植被是控制土壤侵蚀的关键因子,研究植被不同部位的减沙效益及机理对于水土保持、植物保护和恢复具有指导意义。以白三叶(Trifolium repens L.)和红壤为实验对象,采用人工模拟降雨的方式,在坡度15°和雨强60、120、180 mm·h~(-1)条件下,测定完整植株坡面、根系坡面和裸坡的产流产沙过程和流速,研究草本植物完整植株、冠层、根系在红壤坡面的减沙效应及其对坡面径流水动力学参数的影响。研究结果表明,盖度为85%的白三叶平均减沙效益为97.3%,根系、冠层的平均减沙效益分别为66.3%、31.0%,根系的减沙效益显著高于冠层。植被能够降低径流含沙量,尤其是降雨初期的径流含沙量。植被能够降低38.6%的坡面径流流速,其中冠层的平均减速效益为31.2%,根系的平均减速效益为7.3%,冠层的减速效益远大于根系。植被对坡面径流雷诺数影响较小,能够降低径流的弗劳德数,缓解径流流态,但坡面径流都为层流-缓流形态。植被能够显著增加坡面径流的达西-韦斯巴赫阻力系数,冠层的平均增阻效益为402.4%,根系的增阻效益为33.0%。随着雨强的增大,植被的增阻效益降低。白三叶具有良好的调控坡面侵蚀的能力,其中冠层主要通过对坡面径流的流速和阻力的影响来减少坡面侵蚀,而根系的减沙效益要大于其减速和增阻效益。植被调控坡面侵蚀的机理十分复杂,其中根系的减蚀机理需要进一步深入研究。
[Abstract]:Vegetation is the key factor to control soil erosion. It is of guiding significance to study the benefit and mechanism of sediment reduction in different parts of vegetation for soil and water conservation, plant protection and restoration. Trifolium repens L. Under the conditions of 15 掳slope and 60120180 mm ~ (-1) rain intensity, the runoff and sediment yield of intact plant, root slope and bare slope were measured, and the complete plants and canopy of herbaceous plants were studied. Sediment reduction effect of root system on red soil slope and its effect on hydrodynamic parameters of runoff. The results showed that the average sediment reduction benefit of white clover with 85% coverage was 97.30.The average sediment reduction benefit of root system and canopy was 66.3% and 31.0, respectively. The sediment reduction benefit of root system was significantly higher than that of canopy layer. Vegetation can reduce runoff sediment content, especially at the beginning of rainfall. Vegetation can reduce the runoff velocity by 38.6%, and the average deceleration benefit of canopy is 31.2%, the average deceleration benefit of root system is 7.3%, and the deceleration benefit of canopy is much higher than that of root system. Vegetation has little effect on the Reynolds number of slope runoff, which can reduce the Froude number of runoff and alleviate the flow pattern of runoff, but the runoff on the slope is laminar and slow-flow. Vegetation can significantly increase Darcy Weisbach resistance coefficient of slope runoff, the average drag increase benefit of canopy is 402.4 and that of root system is 33.0. With the increase of rain intensity, the benefit of increasing vegetation resistance decreases. White clover has a good ability to control slope erosion. The canopy can reduce slope erosion mainly through the influence of flow velocity and resistance on slope runoff, and the benefit of sediment reduction of root system is greater than that of deceleration and increase resistance. The mechanism of vegetation controlling slope erosion is very complex, and the mechanism of root erosion reduction needs further study.
【作者单位】：广东省生态环境技术研究所//广东省农业环境综合治理重点实验室;广东省科学院;
【基金】：国家自然科学基金项目(41501295) 广东省科学院项目(qnjj201506;Sytz201501) 广东省科技计划项目(2013B091500077;2015B070701017) 水利部公益性行业专项经费项目(201501047) 广东省院创新平台建设专项
【分类号】：S157

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