Soil condition determines how crop residues affect soil compressive characteristics

AbstractExcessive soil compaction is a major cause of environmental problems and reduced agricultural soil productivity. Soil conditions can affect soil compressive characteristics. The application of organic materials reduces soil susceptibility to compaction. However, the direct effect of incorporated organic matter and interactions among soil conditions and incorporated organic materials on soil compressive characteristics are poorly understood. In this study, uniaxial compressive experiments were conducted to determine the compression curves of repacked brown earth from Northeast China. The effect of variable levels of incorporated corn straw (20, 40, 60, 80, and 100 g kg−1) and soil conditions (moisture content 0.14, 0.18, and 0.22 g g−1, and bulk density 1.20, 1.30, 1.45, and 1.60 g cm−3) on the compressive characteristics were investigated. The results showed that compressive characteristics were directly affected by soil conditions and corn straw‐derived organic matter (p < 0.01). Compressive characteristics were also significantly influenced by the interaction between soil conditions and corn straw‐derived organic matter (p < 0.01). By constructing a Entropy Weight Method (EWM) Technique for Order Preference by Similarity to Ideal Solution model (EWM‐TOPSIS), the conflicting indicators of soil resistance was comprehensively evaluated. The evaluation results indicated that moisture content at 0.14 g g−1, bulk density at 1.30 g cm−3 and corn straw‐derived organic matter at 34 g kg−1 was the optimal mode for soil resistance in our experiment. The results suggested that the interaction of soil conditions and incorporated organic matter should be considered to evaluate the susceptibility to compaction in the fields accurately.