Decadal effects of checkerboard barriers of Salix psammophila on soil grain size distribution and erodibility

Abstract

In arid and semi-arid regions of the world, checkerboard barriers of Salix psammophila play a key role in ecological restoration. However, the effects of different ages of checkerboard barriers on soil particle size distribution characteristics and soil erosion resistance are not known. For this study, sand dunes with checkerboard barriers of S. psammophila were selected as the study population, and mobile dunes prior to checkerboard barriers of S. psammophila were used as unconstructed sample plots (CK). We collected soil from the top, middle, and bottom in 0–2 cm soil layers of the dunes unconstruct and under one year (1a), six years (6a), and decade years (10a) of checkerboard barriers of S. psammophila, respectively. We used multiple fractal theory and erodibility K value to reveal the characteristics of soil grain size distribution and erodibility by checkerboard barriers of S. psammophila and elucidated their main influencing factors. Compared with CK, the construct checkerboard barriers of S. psammophila significantly increased soil nutrients and fine particle content with increasing age. In addition, checkerboard barriers altered the distribution patterns of soil nutrients and particle size in different parts of the dunes, with nutrients and fine particles mainly concentrated at the bottom of the dunes. Checkerboard barriers of S. psammophila reduced the width of the soil particle size distribution relative to CK at 1a of construction, but they incresed the dispersion and homogeneity of the soil particle size distribution as the number of years of construction increased. The soil erodibility K values were found to be between 0.087–0.101, 0.083–0.090, 0.068–0.075, and 0.066–0.069 for CK, 1a, 6a, and 10a, respectively. A random forest model identified soil nutrients, grain size composition, multifractal parameters (D1 and D1/D0), and vegetation characteristics as the key factors influencing K values (P < 0.05, R² = 0.902).