The influence of organic litter on the erosive effects of raindrops and of gravity drops released from desert shrubs
The influence of organic litter on the erosive effects of raindrops and of gravity drops released from desert shrubs
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DOI：
10.1016/s0341-8162(99)00050-8
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发表时间：
1999-08-01
期刊：
影响因子：
6.2
通讯作者：
Dunkerley, D
中科院分区：
文献类型：
--
作者：
Geddes, N;Dunkerley, D
本文报道了一项关于水滴冲击对荒漠灌木下枯枝落叶和飞沙的影响的实验室研究。直径5.7毫米的单个水滴从0.5、1.0和1.5米(选择包括典型沙漠灌木的高度范围)的高度释放到裸露或部分被凋落物覆盖的饱和细沙目标上。天然凋落物主要来自盐生灌木滨藜，收集自新南威尔士州西部的荒漠灌木丛。落下的撞击导致沙子和垃圾颗粒都经历了飞溅位移。溅起的沙粒质量随落下高度的增加而增加，而落下颗粒的质量随落下高度的变化不大。表面凋落物以200g/m(2)的速度施用时，飞溅搬运的沙子重量显著减少。这些发现表明，沙漠灌木释放的重力滴可能既提供了这些植物下面的侵蚀力，也提供了一种将植物基地的垃圾分散到周围景观中的手段，在那里，垃圾可能会继续影响水文和侵蚀过程。通过限制矿物颗粒的飞溅，凋落物可以限制灌木下的土壤飞溅，从而可能有助于沙漠灌丛中常见的植物土丘微地形的持久存在。在露天条件下，对流阵雨中的大雨滴必须引起类似的垃圾颗粒的飞溅运输，从而在景观内垃圾的分布中发挥作用。(C)1999 Elsevier Science B.V.保留所有权利。
This paper reports on a laboratory study of the effects of water drop impacts on litter and sand splash beneath desert shrubs. Individual drops of 5.7 mm diameter were released from heights of 0.5, 1.0, and 1.5 m (selected to encompass the height range of typical desert shrubs) onto targets of bare or partially litter-covered, saturated fine sand. The natural litter, largely derived from the saltbush Atriplex vesicaria, was collected from desert shrubland sites in western New South Wales (NSW). The drop impacts caused both sand and Litter particles to undergo splash displacement. The mass of sand splashed was found to increase with drop fall height, while mass of litter particles splashed did not vary significantly with fall height. Weights of sand moved by airsplash were significantly diminished by surface litter applied at the rate of 200 g/m(2). These findings indicate that gravity drops released from desert shrubs may provide both an erosive force beneath these plants, and a means for dispersing litter from the plant base into the surrounding landscape, where litter may continue to affect hydrologic and erosional processes. By restricting splash of mineral particles, litter acts to limit soil splash from beneath shrubs, and in this way may contribute to the persistence of plant mound microtopography that is common in desert shrublands. Under open-field conditions, large raindrops delivered in convective showers must cause similar airsplash transport of litter particles, thus playing a role in the distribution of litter within the landscape. (C) 1999 Elsevier Science B.V. All rights reserved.