Research on Soil Fixation Performance of Native Crop Root‐Reinforced Soil in Sandy Loess Farmland of Sandy Arid Regions: A Wind Tunnel Test Study

Abstract

In the arid and semi‐arid sandy loess area, farmland wind erosion is exacerbated by spring strong winds and long‐term tillage, yet the pathways by which crop roots regulate soil properties and wind erosion resistance remain unclear; to address this, we conducted controlled experiments combining root‐soil composite preparation and wind tunnel simulations, where soil samples were mixed with foxtail millet roots to form root volume density (RVD) gradients of 0%, 0.2%, 0.4%, 0.6% and 0.8% and then exposed to wind speeds of 8–11 m/s at attack angles of 0°, 15° and 30° for 30–120 min, with soil mechanical properties and wind erosion characteristics measured. Results showed that wind erosion intensity decreased exponentially with increasing RVD (maximum 42.7% reduction in the initial stage at 10 m/s wind speed compared to bare soil), soil cohesion increased logarithmically from 3.7 kPa (bare soil) to 9.8 kPa (0.8% RVD), root‐induced additional shear strength contributed 47.5%–158.67% of total shear resistance, soil erodibility (K‐value) declined from 2.61 (bare soil) to 1.49 (0.8% RVD) and root reinforcement mitigated erosion by 44.8%–47.7% across all attack angles. Although erosion intensity decreases with the increase of RVD, it rises with the increase in wind speed. Mechanistic analysis revealed RVD indirectly regulated wind erosion intensity and erodibility by improving soil structural stability and mechanical properties, with RVD identified as the primary factor controlling wind erosion resistance and wind velocity dominating erosion dynamic attenuation, and we established a nonlinear empirical equation for erodibility parameters and RVD incorporating wind velocity and attack angle. This study clarifies root‐mediated wind erosion control mechanisms and provides a low‐cost, sustainable soil conservation strategy for ecologically fragile sandy loess regions.