Impacts of wind erosion on subsequent splash erosion, particle selectivity and aggregate stability in Phaeozems of Northeastern China: indoor simulation study

This study systematically investigated the coupling mechanisms between wind erosion and subsequent splash erosion in three typical Phaeozems (LS, KS, NJ) from northeastern China's black soil region through integrated indoor wind tunnel simulations and artificial rainfall experiments. Data confirmed the core hypothesis: prior wind erosion significantly increased soil surface roughness (SSR increased by 55%-61%) and reduced soil moisture content (SM decreased by 6.1%-11.5%), forming physical barriers and enhancing soil shear strength, thereby suppressing subsequent splash erosion processes. At 60 minutes, splash sediment loads decreased by 5.48%-74.04%, with inhibitory intensities ranking as NJ soil (mean reduction: 56.75%) > LS soil (mean reduction: 44.82%) > KS soil (mean reduction: 35.33%).
A critical finding was the threshold effect governed by clay content (7.22%-12.04%):
In low-clay soil (LS, 7.22%): Wind erosion destabilized aggregates, manifesting as a 19.75% increase in micro-aggregates (<0.25 mm), a 62.56% decrease in macro-aggregates (>2 mm), and a 35.3% reduction in mean weight diameter (MWD).
In high-clay soil (KS, 12.04%): Wind erosion enhanced erosion resistance, with macro-aggregates increasing by 86.07% and MWD rising by 20.0%.
Particle selectivity analysis further revealed:
Wind erosion increased the clay enrichment ratio (ERcl) by 13.34% in NJ soil but reduced its clay aggregate ratio (ARcl) by 12.95%, demonstrating clay's dual role in erosion processes.
Silt consistently dominated particle transport (>70% of splashed sediment, ERsi >1).
Dynamic selectivity showed preferential clay detachment during initial stages (≤12 min), followed by enhanced sand migration in later phases.
These phenomena are attributed to:
Dispersion of raindrop kinetic energy by wind erosion pits;
Suppression of "gas explosion effects" due to reduced moisture;
Differential regulation of aggregate structure by clay cementation.
Conclusion: This study quantifies the coupling mechanisms between wind and water erosion, providing direct experimental evidence and quantitative support for the core scientific question of "how prior wind erosion influences subsequent water erosion processes." These findings establish a fundamental basis for understanding compound wind-water erosion mechanisms.