Purpose

Raindrop impact causes splash erosion, the initial form of water erosion, which splashes and disperses surface soil particles. To date, there have been several wide-ranging studies of the Loess Plateau; however, a single soil type was generally studied. This meant that the large differences in the characteristics of different soil types because of variation in topography and soil-forming conditions were disregarded. The objectives of this research were to clarify the soil aggregate splash characteristics of different soil types under different rainfall conditions on the Loess Plateau.

Materials and methods

This study analysed the soil aggregate mass and distribution of aggregate fractions from splash erosion under six rainfall conditions (raindrop size: 2.67–5.45 mm) at five splash distances (0–10, 10–20, 20–30, 30–40 and 40–50 cm). Five types of soil on the Loess Plateau were selected for this research.

Results and discussion

The results showed that soil properties had a greater effect on aggregate distribution in splash. With the increase in raindrop diameter, the mass from splash erosion of Lou, Linnamon and Dark loessial soils increased. The mass from splash erosion of Loessial and Aeolian sandy soils, however, showed a variable trend as the raindrop diameter increased to a peak at a diameter of 4.05 mm. Soil types with smaller clay contents were more likely to be transported under high rainfall intensity, and increasing raindrop diameter can transport more soil and also break down aggregates. For the same soil type, the distribution of splash aggregate fractions was similar at different splash distances, and the splash mass decreased exponentially as the splash distance increased (P < 0.001). The Aeolian sandy soil had the largest splash mass for each splash distance, and its resistance to soil erosion was poor. A model was developed to predict the splash mass using the soil erodibility factor, splash distance, raindrop diameter and raindrop intensity.

Conclusions

Our findings indicated that compared with rainfall conditions, soil properties had a greater effect on aggregate distribution from splash, indicating that improved soil structure is the main factor that can reduce the water erosion damage.

中文翻译：

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不同雨滴直径下黄土土壤骨料级分的选择性

目的

雨滴的撞击会引起飞溅侵蚀，这是水蚀的最初形式，它会飞溅并分散表层土壤颗粒。迄今为止，对黄土高原进行了几项广泛的研究。但是，通常只研究一种土壤类型。这意味着由于地形和成土条件的变化，不同土壤类型的特性差异很大。本研究的目的是弄清黄土高原不同降雨条件下不同土壤类型的土壤团聚体飞溅特征。

材料和方法

这项研究分析了五个降雨距离（0–10、10–20、20–30、30–40和40）在六个降雨条件（雨滴大小：2.67–5.45 mm）下土壤侵蚀引起的土壤团聚体质量和组分分布–50厘米）。黄土高原上的五种土壤被选择用于这项研究。

结果和讨论

结果表明，土壤性质对飞溅物中骨料分布的影响更大。随着雨滴直径的增加，Lou，Linnamon和Dark黄土土壤飞溅侵蚀的质量增加。黄土和风沙质土壤的飞溅侵蚀产生的质量随雨滴直径增加到4.05 mm的峰值而呈现出变化的趋势。粘土含量较小的土壤类型更容易在高降雨强度下运输，而雨滴直径的增加可以运输更多的土壤，并破坏团聚体。对于相同的土壤类型，在不同的飞溅距离下，飞溅聚集体组分的分布是相似的，并且随着飞溅距离的增加，飞溅质量呈指数下降（P <0.001）。在每个飞溅距离上，风沙质土壤的飞溅质量最大，其对土壤侵蚀的抵抗力很差。开发了一个模型来使用土壤易蚀性因子，飞溅距离，雨滴直径和雨滴强度来预测飞溅质量。

结论

我们的发现表明，与降雨条件相比，土壤性质对飞溅物聚集体分布的影响更大，这表明改善土壤结构是减少水蚀破坏的主要因素。