Effects of different reclamation patterns on soil erodibility and soil nutrients in bauxite mining area of Guangxi, China

Soil erodibility and soil nutrients are the key factors restricting the ecological restoration of mining areas. However, it remains challenging to understand the effects of different reclamation patterns on soil erodibility and soil nutrients in bauxite mining areas of Guangxi, China. In this study, plots under vegetation reclamation pattern (eucalyptus and mulberry) and agricultural reclamation pattern (maize, sugarcane, and sweet potato) were selected in the bauxite mining area of Guangxi, China. Soil physical and chemical properties were used to calculate the comprehensive soil erodibility index (CSEI) and the comprehensive soil nutrient index (CSNI). A coupling coordination model was then constructed to evaluate ecological benefits. The results showed that the CSEI of the vegetation reclamation pattern was higher than that of the agricultural reclamation pattern. The CSNI of the sweet potato plot was 187.56% higher than that of the eucalyptus plot ( p < 0.05). The coupling coordination degrees were ranked as follows: sweet potato (0.85) > maize (0.68) > sugarcane (0.66) > mulberry (0.64) > eucalyptus (0.38). The partial least squares regression analysis indicated that sand content, geometric mean diameter, and water-stable aggregate content were the main factors affecting CSNI, while silt content, clay content, water-stable aggregate content, and fractal dimension were the main factors affecting CSEI. The structural equation model revealed that sand content ultimately affected CSNI by influencing geometric mean diameter and water-stable aggregate content, whereas silt content and clay content showed a significant positive and negative effect on CSEI, respectively. In conclusion, the agricultural reclamation pattern exhibited better ecological benefits in the early stage of reclamation, while soil texture was the key factor controlling soil erodibility and soil nutrients under different reclamation patterns in the bauxite mining area of Guangxi, China, which could provide a reference for land reclamation and soil and water conservation measures.