LAUSR

This study sought to investigate the influence of different land types on soil enzyme activities and identify the driving factors behind it. Three prevalent land cover types and one land use type by Qinghai Lake were selected (original wetland, natural grassland, recovered shrubland, and farmland), and the surface soil at a depth of 0–10 cm was collected for analysis. The results indicated that soil organic carbon, active carbon, dissolved organic carbon, total nitrogen content, microbial biomass, and soil hydrolase activity decreased, whereas phenol oxidase activity increased after converting the wetland into other land types. However, the differences in microbial biomass and enzyme activities between farmland and recovered shrubland were not significant. Similar trends in β-glucosidase and cellobiohydrolase activities were detected and these were more sensitive to the changes in land types. Soil carbon and nitrogen contents were shown to be responsible for the variability in hydrolase activity, with active carbon showing the strongest influence. Wetland conversion induces the loss of soil carbon and nitrogen stock, which may further decrease the availability of organic matter for microbes. A decrease in hydrolase activity and an increase in phenol oxidase activity may indicate shifts in organic carbon bioavailability after wetland conversion.