Effects of gullies on the spatiotemporal variability of soil-water under different vegetation types on the Loess Plateau

Gullies are pervasive topographic features on the Loess Plateau. We selected two typical gullies in the water-wind erosion region of the plateau to study the effect of gullies on the spatiotemporal variability of soil-water. The distribution and variation of soil-water storage were evaluated using time-series analysis and classical statistical methods. Soil-water storage varied with distance to the gully borders. The spatial average soil-water in the study sites was 300 cm from the border. soil-water in the vertical direction was mostly dependent on the vegetation, and the gullies had little impact. The spatial distribution of soil-water at a slope scale presented different patterns. Strong upland winds increased the evaporation of soil-water, which rapidly dissipated. Soil-water storage at mid-slope near the gullies was as high as 949.9 mm. The bottom of the slopes had soil-water deficits of 4%. Soil-water storage was much higher in an apricot orchard than in shrubland dominated by Caragana korshinskii Kom. Soil evaporation, vegetation type, and the gullies increased the complexity of the pattern of soil-water.