Crushing energy-based indicators of dry soil aggregate stability from contrastive land management practices in a semi-arid agroecosystem

Abstract

Dry soil aggregate stability (DAS) is a critical indicator of soil quality and a significant factor influencing soil wind erosion in arid and semi-arid agroecosystems. Previous research primarily used aggregate size distribution, determined through “dry sieving,” to describe DAS. However, the standardization of “dry sieving” has faced criticism, and the resultant DAS based on particle size distribution (DAS_%) does not effectively reflect the aggregate's resistance to abrasion. To address this issue, we aimed to develop a novel quantitative analysis method and indicator based on aggregate crushing energy (DAS_Jkg⁻¹) and validate this procedure by comparing it with DAS_% and aggregate Geometric Mean Diameter (GMD). We selected 58 research sites with varying land management practices (e.g., crop rotation, tillage, and irrigation) in the lower FloodPlain of the Yellow River (FPYR) to quantitatively evaluate the wind stability of farmland aggregates. Our findings show a significant exponential increase in DAS_Jkg⁻¹ (0.2121$e^{0.0451x}$) corresponding to increasing DAS_% (x) for aggregates that remained relatively stable (> 61 %). Conversely, a weak correlation was observed between the GMD of aggregates (x) and DAS_Jkg⁻¹. Our results suggest that DAS_% can be used to assess the abrasion flux of aggregates under certain conditions by converting it to DAS_Jkg⁻¹. Additionally, crop rotation and irrigation had a substantial impact on DAS_Jkg⁻¹, with flood-affected plots exhibiting a significantly higher DAS_Jkg⁻¹ (86 %) than that exhibited by non-flooded plots. These findings provide valuable insights into improving soil management practices to mitigate wind erosion and for the restoration ecology of degraded farmland.