Litter decomposition is the main source of soil organic carbon (SOC) pool, regarding as an important part of terrestrial ecosystem C dynamics. The turnover of SOC is mainly regulated by extracellular enzymes secreted by microorganisms. However, the response mechanism of soil C-degrading enzymes and SOC in litter decomposition remains unclear. To clarify how SOC fraction dynamics respond to C-degrading enzymes in litter decomposition, we used eld experiments to collect leaf litter and SOC fractions from the underlying layer in Robinia pseudoacacia plantations on the Loess Plateau. Our results showed that soil SOC, easily oxidizable organic C, soluble organic C and microbial biomass C increased signi cantly during the decomposition process. Litter decomposition signi cantly decreased soil hydrolase activity, but slightly increased oxidase activity. Correlation analysis results showed that SOC fractions were signi cantly positively correlated with the litter mass, lignin, soil moisture, and oxidase activity, but signi cantly negatively correlated with cellulose content and soil pH. Partial least squares path models revealed that the most direct factors affecting the SOC fractions of topsoil during litter decomposition were litter lignin and cellulose degradation, soil pH, and C-degrading enzymes. Furthermore, regression analysis showed that the decrease of SOC stability in litter decomposition was closely related to the decrease of soil hydrolase: oxidase ratio. These results highlighted that litter degradation-induced changes in C-degrading enzyme activity signi cantly affected SOC fractions. Furthermore, the distribution of soil hydrolase and oxidase modulated the stability of SOC during litter decomposition. These ndings provided a theoretical framework for a more comprehensive understanding of C turnover and stabilization mechanisms between plant and soil.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.