Spatio-temporal variations of soil particle size distribution under wind erosion in a temperate grassland: A seven-year landscape scale revisited analysis

The soil particle size distribution (PSD) is generally perceived as stable as its change by pedogenesis is slow, but it actually undergoes dynamic spatio-temporal changes under the influences of surface processes, especially wind erosion due to its strong sorting effect. In areas with active surface processes like the wind eroded area, PSD dynamically changes (PSDD) as a result of the aeolian erosion and deposition in complementary to the local pedogenesis. Such PSDD is of great importance for understanding soil quality and optimize soil management, however, it is neglected in existing studies. This study analyzed the spatial variability of PSDD and its main influencing factors at depths of 0–1 cm and 1–6 cm in the Xilingele grassland, a typical temperate grassland, using revisited sampling from 2014–2021. The results indicate that in 0–1 cm, the clay increased by 4.76 %, the silt decreased by 1.08 % and the sand decreased by 3.65 %. In 1–6 cm, the clay increased by 2.36 %, the silt increased by 0.18 % and the sand decreased by 1.85 %. Spatial autocorrelation of PSD was moderate in both years, but the spatial heterogeneity decreased from 2014–2021 as dedicated nugget to sill ratio and range. The spatial pattern of PSD showed little temporal variation, with clay content in the 0–1 cm of western steppe and cultivated land increasing more than in mountainous areas, and sand content decreasing more on windward slopes than on flatlands and leeward slopes. The decrease in land use intensity contributed to an increase in clay content in vegetation restoration areas. Wind erosion exhibited a weakening trend in the study area during 2014–2021, but some hot spot areas still experience severe erosion. The decrease in wind erosion is a key factor in the increase in clay content in the region, with land use management contributing to the wind erosion reduction.