Impact of multi-day rainfall events on surface roughness and physical crusting of very fine soils
Impact of multi-day rainfall events on surface roughness and physical crusting of very fine soils
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DOI：
10.1016/j.geoderma.2017.10.038
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发表时间：
2018-03
期刊：
影响因子：
6.1
通讯作者：
J. Bullard;A. Ockelford;C. Strong;H. Aubault
中科院分区：
文献类型：
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作者：
J. Bullard;A. Ockelford;C. Strong;H. Aubault
土壤表面粗糙度（SSR）是对土壤微地形的描述，它影响着土壤表面的蓄水能力，影响着风蚀和水蚀的临界流量，并决定着一系列尺度上陆地和大气系统之间的相互作用和反馈过程。降雨是SSR的一个重要决定因素，因为它可以导致土壤颗粒的错位、重新定向和堆积，并可能导致形成物理土壤结皮，而物理土壤结皮又会影响土壤的粗糙度和水文特性。本文介绍了一个实验，调查多日降雨事件的SSR和物理结皮的有机质含量低，典型的半干旱环境的非常细的土壤的影响。SSR的变化是使用地理学衍生的指标量化的，这些指标是通过对以78 μm（0.078 mm）的水平分辨率和12 μm（0.012 mm）的垂直分辨率捕获的土壤表面的高分辨率激光扫描进行半变异函数分析计算的。施加2 mm、5 mm和2 mm的降雨，每种降雨间隔24 h干燥期，导致土壤形成结构性双层“筛”壳，其特征为表面上覆盖细颗粒薄密封的桑迪微层。地质统计学和土壤特性（如质地，表面电阻，渗透率）的分析表明，在这种规模的查询，并为低降雨量，垂直和水平分量的SSR是由雨滴的影响，而不是总的故障。这可能是由于土壤性质非常好，降雨量很低。
Soil surface roughness (SSR), a description of the micro-relief of soils, affects the surface storage capacity of soils, influences the threshold flow for wind and water erosion and determines interactions and feedback processes between the terrestrial and atmospheric systems at a range of scales. Rainfall is an important determinant of SSR as it can cause the dislocation, reorientation and packing of soil particles and may result in the formation of physical soil crusts which can, in turn, affect the roughness and hydrological properties of soils. This paper describes an experiment to investigate the impact of a multi-day rainfall event on the SSR and physical crusting of very fine soils with low organic matter content, typical of a semi-arid environment. Changes in SSR are quantified using geostatistically-derived indicators calculated from semivariogram analysis of high resolution laser scans of the soil surface captured at a horizontal resolution of 78 μm (0.078 mm) and a vertical resolution of 12 μm (0.012 mm). Application of 2 mm, 5 mm and 2 mm of rainfall each separated by a 24 h drying period resulted in soils developing a structural two-layered ‘sieving’ crust characterised by a sandy micro-layer at the surface overlying a thin seal of finer particles. Analysis of the geostatistics and soil characteristics (e.g. texture, surface resistance, infiltration rate) suggests that at this scale of enquiry, and for low rainfall amounts, both the vertical and horizontal components of SSR are determined by raindrop impact rather than aggregate breakdown. This is likely due to the very fine nature of the soils and the low rainfall amounts applied.