Soil density and oscillation frequency are some of the main factors affecting soil micromechanical behavior, but their role in the oscillatory amplitude sweep test (AST) is not yet well understood. Current studies use either a reference density, i.e. field density or a density based on texture and/or organic matter content or opt for a common density for all samples, while oscillation frequency may be relevant in simulating agricultural traffic speeds and affects coupled hydraulic-mechanical processes. We analyzed the effect of soil density and AST oscillation frequency at different matric potentials of three weathered Oxisols from southern Brazil that were repacked to different densities, namely different levels of compaction, no compaction and field density. Higher density, probably due to increased cohesion and friction, increased rheological shear stress parameters: shear stresses at the end of the linear viscoelastic range (LVR), τ_L; and at the yield point (YP), τ_YP; and storage and loss moduli (G’ and G”, respectively) at the YP, G’, G”_YP. However, viscoelasticity parameters: strain at the end of LVR γ_L; strain at the YP γ_YP; and the integrated zone I_z, were negatively affected at low densities with increasing magnitude at higher density levels. Uncompacted soil resulted in densities similar to field density, and delimitated a soil state where density does not interfere with friction. This suggests a methodology for the comparison of distinct soils or where information on field density is missing or unavailable. Frequency alterations from 0.25 to 1.0 Hz had low impact and only increased few rheological parameters, mainly in some soils drained at −6 kPa, but neither reduced data accuracy nor affected the samples' evaporation. Hence, rheological tests can be executed at a higher frequency than 0.5 Hz (at least up to 1.0 Hz) to increase sample output. For both density and frequency, (i) drainage increased soils micromechanical resistance due to water menisci; and (ii) soil resistance showed the order: Typic Hapludox (clayey brown-reddish Oxisol) > Rhodic Kandiudox (clayey red Oxisol) > Rhodic Hapludox (sandy red Oxisol), mainly due to the cohesive effect of clay and Fe oxides, as well as the aggregating effect of soil organic matter.

土壤密度和振荡频率是影响土壤微机械性能的一些主要因素，但它们在振荡振幅扫描测试（AST）中的作用尚未得到很好的理解。当前的研究使用参考密度，即场密度或基于质地和/或有机物含量的密度，或为所有样品选择通用密度，而振荡频率可能与模拟农业交通速度有关，并会影响水力机械耦合。流程。我们分析了巴西南部三种风化的气溶胶的不同基质势对土壤密度和AST振荡频率的影响，这些气溶胶重新包装成不同的密度，即不同的压实度，没有压实度和田间密度。更高的密度，可能是由于内聚力和摩擦力的增加，_L ; 在屈服点（YP）处，_τYP；以及在YP，G'，G” _YP处的存储和损耗模量（分别为G'和G”）。然而，粘弹性参数：应变LVRγ的端_大号; YP处的应变_γYP ; 和积分区I _z，在低密度时受到负面影响，在更高密度时幅度增加。未压实的土壤导致了类似于田间密度的密度，并界定了密度不干扰摩擦的土壤状态。这提出了一种比较不同土壤或缺少或缺乏田间密度信息的方法。从0.25到1.0 Hz的频率变化影响不大，仅增加了很少的流变参数，主要是在某些以-6 kPa排水的土壤中，但既没有降低数据准确性也不影响样品的蒸发。因此，可以以高于0.5 Hz（至少高达1.0 Hz）的频率执行流变测试，以增加样品输出。对于密度和频率，（i）由于水的弯液面，排水增加了土壤的微机械阻力；