Impact of soil compaction on the rill erosion of Mollisol by waterflow: A comparative analysis before and after the seasonal freezing and thawing

Abstract

Soil erosion resulting from soil compaction and freeze-thaw action is a major global environmental issue in intensively mechanized agricultural and cold regions. Existing studies predominantly focus on the direct effects of freeze-thaw cycles on soil erosion, yet overlook the legacy effects of pre-freeze-thaw soil compaction. This study aimed to reveal the cross-temporal impact mechanisms of pre-freeze-thaw soil compaction on post-freeze-thaw soil erosion and how soil properties drive these effects. A comparative study was conducted in the Mollisol region of Northeast China by utilizing in situ field erosion experiments and soil property measurements under various compaction levels before and after the freeze-thaw period. Results showed that before the freeze-thaw period, compaction significantly increased total runoff and sediment mass (p < 0.05). After the freeze-thaw period, the sediment mass of compacted soil decreased by 1.84 %–57.73 % compared to before the freeze-thaw period, but still increased by 28.59 %–148.22 % compared to uncompacted soil. The structural equation model revealed that before the freeze-thaw period, the influence of soil properties on runoff was greater than their direct effect on sediment mass, and the sediment mass variation was mainly driven by runoff scouring due to soil compaction. After the freeze-thaw period, the decreased soil erosion resistance (aggregate stability and soil strength) and the increased runoff caused by the legacy effects of compaction were the primary reasons for higher sediment mass in compacted soil compared to uncompacted soil. This study highlights the crucial role of human activities before the freeze-thaw period in influencing subsequent erosion dynamics, providing essential insights for erosion control and soil restoration in vulnerable farmlands.