模拟降雨条件下侧柏林地枯落物对坡面产流产沙的影响

发布时间：2018-03-31 23:09

本文选题：北京山区　切入点：林地坡面　出处：《水土保持学报》2017年03期

【摘要】：以北京山区人工侧柏林地坡面为研究对象,基于2个2m×5m径流小区,设枯落物覆盖自然坡面与裸露坡面2种处理、大小2种雨强(126,70mm/h),通过对比分析2种处理下坡面产流产沙过程,揭示林下枯落层覆盖对北京山区坡面产流产沙的影响。结果表明:(1)与裸坡相比,枯落物覆盖自然坡面产流产沙分别减少了67.0%和90.6%,其中,减沙效益大于减水效益。(2)无论是枯落物覆盖自然坡面还是裸坡,坡面产流过程均表现为先增大后趋于稳定的变化规律,但枯落物覆盖坡面产流趋于稳定的时间较裸坡有所提前。(3)枯落物覆盖坡面70,126mm/h降雨平均产沙速率分别为2.8,80.8g/min,裸坡分别为51.4,872.7g/min,枯落物覆盖坡面产沙率显著小于裸坡(p0.05)。当地表有枯落物覆盖时,产沙速率与含沙量随产流历时均波动变化不大,坡面产沙是一个基本稳定的过程;于裸坡而言,产沙速率与含沙量在小雨强条件下呈现先增加后趋于稳定的变化规律,而大雨强条件下,两者随产流历时先急剧增加后波动降低。(4)枯落物覆盖坡面产沙量与产流量为线性关系,而裸坡产沙量随产流量的增加呈幂函数急剧上升。研究结果可为评价北京山区人工林恢复水土保持效益提供理论依据,同时增进了对北京山区林地坡面产流产沙机制的认识。
[Abstract]:Taking artificial Platycladus orientalis forest land in Beijing mountainous area as the research object, based on 2 2 m 脳 5 m runoff plots, two treatments were set up to cover the natural slope and bare slope, and two kinds of rain intensity of 126 ~ 70mm / h ~ (-1) were used to analyze the abortion and sediment production process of the two treatments. The results showed that the effect of litter cover on runoff and sediment yield was 67.0% and 90.6% less than that on bare slope, respectively. The benefit of sediment reduction is greater than that of water reduction. (2) regardless of whether the litter covers the natural slope or the bare slope, the runoff production process of the slope is increased first and then tends to stable. However, the time of runoff stabilization on litter cover slope was earlier than that on bare slope.) the average sediment yield rate of 70126mm/h rainfall on sloping slope covered by litter was 2.8g / min and 51.4872.7 g / min, respectively. The sediment yield rate of litter covered slope was significantly lower than that of bare slope (p0.05.) the average sediment yield rate of litter covered slope was lower than that of bare slope, and the average sediment yield rate of litter covered slope was 2.8g / min and 51.4872.7g / min, respectively. When the surface is covered with litter, The sediment yield rate and sediment concentration fluctuate little with the runoff duration, and the sediment yield on the slope is a stable process, and the sediment yield and sediment content increase firstly and then tend to stable under the condition of light rain, for bare slope, the sediment yield and sediment content of the slope tend to be stable at first, and the sediment yield and sediment content on the slope tend to be stable under the condition of light rain. However, under the condition of heavy rain, the sediment yield on the slope covered by litter is linearly related to the runoff yield, which increases sharply and then decreases with the runoff duration. However, the sediment yield of bare slope increases sharply with the increase of yield and discharge. The results can provide a theoretical basis for evaluating the benefit of soil and water conservation of artificial forest in Beijing mountainous area, and improve the understanding of the mechanism of abortion and sediment production on the slope surface of forest land in Beijing mountainous area.
【作者单位】：北京林业大学水土保持学院;北京林业大学北京市水土保持工程技术研究中心;北京林果业生态环境功能提升协同创新中心;
【基金】：国家科技支撑计划项目“华北土石山区防护林体系定向调控技术研究与示范”(2015BAD07B0302) 国家自然科学基金项目(41501292) 科技创新服务能力建设—协同创新中心—林果业生态环境功能提升协同创新中心项目(PXM2017_014207_000043)
【分类号】：S714.7

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