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Rocky desertification is a devastating process in Karst areas of Southwest China and induces serious fragmentation in ecosystems. Therefore, vegetation restoration and the scientific evaluation of soil quality are key restorative strategies in these areas. In this study, a natural closed forest and a disturbed forest with three restoration models, including an evergreen broad-leaved forest, mixed forest, and deciduous forest, were investigated in Huanjiang County. More than nineteen soil properties (including physical, chemical, and biotic properties) were analyzed across treatments, and principal component analyses (PCA) were combined with a minimum data set (MDS) applied to evaluate the soil quality. Our study sought to identify a vegetation restoration model to improve the soil quality in this area. We demonstrated that soil physical and chemical properties, microbial biomass, and enzyme activities significantly differed across all of the models. Soil water content, capillary porosity, total porosity, organic carbon, total phosphorus, available phosphorus, and urease activity were high in the mixed forest, leading to better physical soil properties. Also, relatively high soil total nitrogen, total potassium, available nitrogen, available potassium, microbial biomass C and N, catalase, sucrose, and alkaline phosphatase levels were observed in the deciduous broad-leaved forest, resulting in improved soil chemical properties. Based on the minimum data set (MDS) method, six indicators, including non-capillary porosity, organic carbon, total phosphorus, pH, microbial biomass nitrogen, and urease activity, were selected to evaluate the soil quality across the models. Our data showed that, among the five models, the deciduous broad-leaved forest had the highest soil quality index (0.618), followed by the mixed forest (0.593). Stepwise regression analysis showed that soil organic carbon explained 79.9% of the variations in the soil quality indices, suggesting it was a major factor affecting the soil quality. Thus, vegetation restoration models mainly comprised of native tree species effectively improved the soil quality in Karst rocky desertification areas, with deciduous broad-leaved forests displaying the best effects, followed by mixed forests. [ABSTRACT FROM AUTHOR]

• The construction of deciduous broad-leaved forest having the greatest effect. • PH, soil microbial biomass carbon, and urease activity significantly increased bacterial diversity. • PH and soil microbial biomass carbon and nitrogen were the key driving factors of the soil bacterial community. • Sucrase activity can promote the increase of phototrophy functional bacteria. The karst area in southwestern China is one of the largest and continuous karst landforms in the world, and its ecosystem is highly sensitive and fragile. Appropriate vegetation restoration modes are of great significance for sustaining and improving the stability of the karst ecosystem, the dominant landform type in southwest China. Bacteria, linking soil and plants, play an important role in regulating the succession and restoration of karst vegetation. However, it remains unclear how soil bacterial communities and soil biochemical properties respond to vegetation restoration practices in karst areas. In this study, a 13-year long-term trial was performed using three planting restoration modes of deciduous broad-leaved, mixed evergreen and deciduous broad-leaved forest, and evergreen broad-leaved forests, with controls of natural enclosure. We aimed to investigate the impact of different vegetation restoration modes on the structure of soil microbial communities and their driving mechanisms using 16S rDNA Illumina sequencing, combined with the determination of 11 soil indicators and statistical models. The results showed that artificial restoration can improve soil nutrient contents, enzyme activities and microbial biomass more effectively than natural closure, which is beneficial to the rapid restoration of vegetation after abandoning of farmland. Among them, the effect of deciduous broad-leaved treatment on artificial restoration mode was better than that of mixed evergreen and deciduous broad-leaved forest and evergreen broad-leaved forest. In sequencing results, artificial restoration increased the relative abundance of Proteobacteria, but decreased that of Acidobacteria. In addition, pH, soil microbial biomass carbon, and urease activity significantly increased bacterial diversity. Different vegetation restoration measures significantly changed the soil bacterial community structure. The bacterial community of deciduous broad-leaved forest was the most beneficial to the benign development of soil. Mantel test showed that pH and soil microbial biomass carbon and nitrogen were the key driving factors of the soil bacterial community. FAPROTAX analysis showed a significant positive correlation between sucrase activity and phototrophy functional bacteria. The results demonstrated that compared with natural enclosure, artificial vegetation restoration promoted rapid community succession, and construction of deciduous broad-leaved forest was the most effective way to manage karst areas, improve soil nutrients, alter its key microbial populations, promote ecosystem services, and eventually benefit the restoration of vegetation in karst areas. [ABSTRACT FROM AUTHOR]