Institute of Agrophysics, Polish Academy of Sciences, Lublin, Poland.
PLoS One. 2022 Jan 7;17(1):e0262203. doi: 10.1371/journal.pone.0262203. eCollection 2022.
Soil splash is the first step in the process of water erosion, where impacting raindrops cause the detachment and transport of soil material. One of the factors that strongly influences the magnitude of soil splash is the incline of the surface (slope). The aim of this study was to investigate the effect of the slope on the course of the splash phenomenon caused by single-drop impact (one drop impact per soil sample), with respect to the mass and proportions of the ejected material, taking into account its division into solid and liquid phases i.e. soil and water. The investigation was carried out using three types of soil with different textures, in moistened (pressure head corresponding to -1.0 kPa) and air-dry (-1500 kPa) conditions. The soil samples were on three angles of slope, being 5°, 15°, and 30°, respectively. After a single-drop impact with a diameter of 4.2 mm, the ejected material was collected using a splash cup. The following quantities of splashed material were measured: the total mass, the mass of the solid phase, and the mass of the liquid phase. Additionally, the distribution and proportions (soil/water) of the splashed material were analysed in both the upslope and downslope directions. It was found that: (i) the change of slope had a variable influence on the measured quantities for different soils; (ii) in the case of moistened samples, the measured values were mainly influenced by the texture, while in the dry samples, by the angle of the slope; (iii) with the increase of slope, the splashed material was mostly ejected in the downslope direction (irrespective of moisture conditions); (iv) in the moistened samples, the ejected material consisted mostly of water, while in the dry samples it was soil-this occurred for material ejected both upslope and downslope. The obtained results are important for improving the physical description of the process of splash erosion. A more thorough understanding and better recognition of the mechanisms governing this phenomenon at all stages could contribute to the development of more effective methods for protecting soil against erosion.
土壤飞溅是水蚀过程的第一步，其中冲击雨滴会导致土壤物质的脱离和运输。强烈影响土壤飞溅程度的因素之一是表面的坡度（slope）。本研究的目的是研究单滴冲击（每个土壤样品冲击一次）引起的飞溅现象的过程中，坡度对其的影响，特别是考虑到喷出物质的质量和比例，以及将其分为固相与液相（即土壤和水）。该研究使用三种不同质地的土壤，在湿润（压力水头对应于-1.0 kPa）和风干（-1500 kPa）条件下进行。土壤样品分别位于 5°、15°和 30°的三个坡度上。在直径为 4.2 毫米的单滴冲击后，使用飞溅杯收集喷出的材料。测量了以下喷出物质的数量：总质量、固相质量和液相质量。此外，还分析了上下坡方向上喷出物质的分布和比例（土壤/水）。结果表明：（i）对于不同的土壤，坡度的变化对测量值的影响是可变的；（ii）在湿润样品的情况下，测量值主要受质地的影响，而在干燥样品的情况下，主要受坡度角的影响；（iii）随着坡度的增加，喷出的物质主要向坡下方向喷出（无论水分条件如何）；（iv）在湿润的样品中，喷出的物质主要是水，而在干燥的样品中则是土壤，无论是向上坡还是向下坡喷出的物质都如此。研究结果对于改进土壤飞溅侵蚀过程的物理描述非常重要。对该现象各阶段的控制机制有更深入的理解和更好的认识，有助于开发更有效的土壤侵蚀保护方法。
