Soil erosion is the first threat to soil functions. Reducing the soil aggregate breakdown strength is a key step to improve the soil’s ability to resist rainfall splash erosion. Soil internal forces have been found to be the initial and important forces driving aggregate turnover. The application of exogenous organic materials can effectively improve soil aggregate stability and the resistance to rainfall erosion of agricultural soils. However, from the perspective of soil internal forces, information about the reduction effects of the exogenous organic materials application on soil aggregate breakdown is scarce, especially in comparing the effects of different materials. In this study, weathered coal and biochar were individually applied to loamy clay soil at rates of 0 %, 1 %, 2 %, and 3 % (w/w). Soil internal forces, aggregate breakdown strength, and splash erosion rate of different amended soils were then examined after four years. The results showed that compared with unamended soils (0 %), both weathered coal and biochar applications clearly increased the van der Waals attractive pressure and thus decreased the positive net pressure between soil particles. Additionally, these materials reduced soil aggregate breakdown strength and splash erosion rate. The application effects of the two materials were increased with their application rates. Under a lower electrolyte concentration in soil solution (0.0001 mol L), the aggregate breakdown strength in the soils amended with weathered coal was lower than that with biochar by 9.6 %, 23.2 %, and 17.7 % (when the diameter of broken aggregate was < 10 μm) and by 10.3 %, 20.8 %, and 17.5 % (when the diameter of broken aggregate was < 20 μm) at the 1 %, 2 %, and 3 % application rates, respectively ( < 0.05). Additionally, soils amended with weathered coal exhibited lower splash erosion rates compared to those amended with biochar, particularly at the higher application rate of 3 %. From the viewpoint of soil internal forces, weathered coal appears to be a suitable exogenous organic material for improving soil aggregate stability and anti-erosion ability during rainfall events. Our findings provide valuable insights into utilizing exogenous materials to improve soil resistance to rainfall splash erosion, assisting agricultural soil management in areas frequently affected by rainfall erosion.

中文翻译：

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用风化煤改良的土壤比用生物炭改良的土壤表现出更大的抗聚集体分解能力：从土壤内力的角度来看


水土流失是对土壤功能的首要威胁。降低土壤团聚体击穿强度是提高土壤抵抗降雨溅蚀能力的关键步骤。人们发现土壤内力是驱动总量周转的最初且重要的力量。外源有机材料的施用可以有效提高土壤团聚体稳定性和农业土壤抵抗降雨侵蚀的能力。然而，从土壤内力的角度来看，关于外源有机材料的施用对土壤团聚体分解的减少效果的信息很少，特别是在比较不同材料的效果时。在这项研究中，风化煤和生物炭分别以 0%、1%、2% 和 3%（w/w）的比例施用于壤质粘土。四年后，对不同改良土壤的土壤内力、骨料击穿强度和飞溅侵蚀率进行了检查。结果表明，与未改良的土壤（0％）相比，风化煤和生物炭的应用都明显增加了范德华吸引压力，从而降低了土壤颗粒之间的正净压力。此外，这些材料还降低了土壤团聚体的击穿强度和飞溅侵蚀率。两种材料的使用效果均随使用量的增加而增强。在土壤溶液电解质浓度较低（0.0001 mol·L）下，风化煤改性土壤的团聚体击碎强度比生物炭改性土壤的团聚体击碎强度分别低9.6%、23.2%和17.7%（破碎团聚体直径为%时）。 3C 10 μm），施用量为 1 %、2 % 和 3 %（< 0.05）时，分别减少 10.3 %、20.8 % 和 17.5 %（破碎骨料直径为 < 20 μm 时）。 此外，与用生物炭改良的土壤相比，用风化煤改良的土壤表现出较低的飞溅侵蚀率，特别是在 3% 的较高施用率下。从土壤内力的角度来看，风化煤似乎是一种合适的外源有机物质，可以提高土壤团聚体稳定性和降雨过程中的抗侵蚀能力。我们的研究结果为利用外源材料提高土壤对降雨飞溅侵蚀的抵抗力提供​​了宝贵的见解，有助于经常受到降雨侵蚀影响的地区的农业土壤管理。