Current research on the impacts of biochar (BC), an organic compound used as soil amendment, focuses on soil physical and chemical properties, such as nutrient or water retention, while little attention is paid to the effects on soil mechanical behavior, especially on the microscale. Our objective was to investigate how BC amendment impacts the microscale mechanical behavior of a weathered soil under oscillatory stresses. Substrates were prepared by mixing soil with two BC types obtained from rice and soybean straw (application rate: 10 t ha⁻¹) and incubating the mixture. Disturbed soil samples were collected 15, 30, 45, and 60 days after mixing to conduct rheological tests to characterize the soil microstructural stability and shear behavior. Along the incubation (except for at 45 days), the BC amendment decreased the soil shear strength in the order of treatments: rice BC-amended soil = soybean BC-amended soil > unamended soil (control). A possible cause, the lubricating impact of increased water retention and low aggregation potential of BC, is discussed. The soil viscoelasticity was not affected by biochar application. Already shear stresses of moderate intensity caused structural breakdown of the BC-amended soil, making it more susceptible to deformation and erosion processes.

目前对用作土壤改良剂的一种有机化合物生物炭（BC）的影响的研究侧重于土壤的物理和化学特性，例如养分或保水性，而对土壤机械性能的影响却很少引起关注，尤其是对土壤力学特性的影响。微量。我们的目的是研究BC修正如何在振荡应力下影响风化土壤的微观力学行为。通过将土壤与两种稻米和大豆秸秆的BC型土壤混合（施用量：10 t ha ^-1）来制备基质）并孵育混合物。混合后15、30、45和60天收集扰动的土壤样品，进行流变测试，以表征土壤的微观结构稳定性和剪切行为。在孵化过程中（45天除外），BC改良剂按处理顺序降低了土壤的抗剪强度：水稻BC改良的土壤=大豆BC改良的土壤>未改良的土壤（对照）。讨论了可能的原因，即保水性增加和BC凝聚力低的润滑作用。土壤粘弹性不受生物炭施用的影响。中等强度的剪切应力已经导致BC改良土壤的结构破坏，使其更易于变形和侵蚀过程。