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Impact of raindrop sizes and intensities on the microcharacteristics of soil aggregates
  • +2
  • Mingxi Yang,
  • Gangan Ma,
  • guangluli li,
  • Yangyang Ren,
  • Zefang Li
Mingxi Yang
Northwest Agriculture and Forestry University
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Gangan Ma
Northwest Agriculture and Forestry University College of Resources and Environment
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guangluli li
northwest A & F University
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Yangyang Ren
Northwest A&F University
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Zefang Li
Northwest A&F University
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Abstract

Aggregate breakdown caused by the impact of raindrops clogs soil pores, reduces soil infiltration and aggravates the formation of soil crusts. To determine the influence of raindrop splash on the microstructure of soil aggregates, the typical loess was studied. We used synchrotron-based X-ray microcomputed tomography (SR-μCT) to analyze the microcharacteristics of soils impacted by rainfall intensities. The results showed that raindrop splash increases the number of surface soil aggregates, especially when the rainfall intensity is 68.61 or 217.26 mm h-1. Compared to the undisturbed soil, the number of soil aggregates increased by 38.71%, 46.77% and 76.77%, and the volume increased by 1.09%, 3.21% and 3.73%, after the impact of rainfall intensities of 5.76, 68.61 and 217.26 mm•h-1, respectively. Raindrop impact on the surface affects the distribution of aggregate particles, causing a decrease in the number of aggregate particles in the 500-1000 μm range and an increase in the < 500 μm range. Compared with unsplashed soil, there is a significant increase in the fractal dimension (FD) and total specific surface area (SSA) of surface soil aggregates in splashed soil. Particularly, the rainfall intensity of 217.26 mm h-1 resulted in an increase of the FD and SSA by 30.24% and 17.49%, respectively. Under the rainfall intensities, the average particle diameter of the soil aggregates decreased by 2.43%, 3.25% and 3.55%, respectively, compared with that of the undisturbed soil. These results indicated that raindrop splash decreased the number of macroaggregates and increased the number of microaggregates in the surface layer of soil.