Soil Multifunctionality Was Determined by Land Cover and Soil‐Microbiological Properties in the Karst Region

ABSTRACT Under the background of the large‐scale Grain for Green Project (GGP) in southwest China, studies have primarily examined the impacts of vegetation restoration on individual soil functions. However, there is a pressing need to intensify research on soil multifunctionality (SMF). By using random forest and structural equation model, this research examined the variation of SMF across three land cover (LC) types, using karst converted crop to forest and grassland, and explored the relationship between SMF and factors such as LC, soil properties, diversity, and the complexity of the co‐occurrence network of microbiology. The nutrient supply, labile organic matter (LOM) decomposition, SMF in grassland soil, and LOM decomposition in plantation soil were significantly higher than those in crop, by 21.66%, 88.35%, and 41.92%, respectively. Conversely, the nutrient supply and SMF in plantation soil were significantly smaller than those in crop. Fungal richness, phylogenetic diversity, and complexity of the microbial co‐occurrence network in grassland and plantation soil were significantly higher than those in crop. Random plantation model analysis indicated that LC, soil moisture (SM), soil pH, and bacterial network complexity (BNC) were the main influencing factors of SMF. The structural equation model demonstrated that SM and soil pH significantly affected BNC, thereby influencing SMF. These findings suggested that SMF was determined by LC and soil‐microbiological properties in the karst region. Furthermore, soil BNC influenced SMF by regulating microbial interspecies relationships (symbiotic). These insights may contribute to understanding the impact mechanism of reforestation and grassland on SMF in karst areas from a soil microorganism perspective.