Microbial keystone taxa and nitrogen cycling enzymes driven by the initial quality of litter jointly promoted the litter decomposition rates in the Tengger Desert, northern China

The initial quality of litter, specifically the chemical composition, is an important factor in determining litter decomposition rates (K). However, further investigation is imperative to elucidate the underlying mechanism governing the impact of initial litter quality on K. We conducted a 420-day field litter decomposition experiment in the artificial sand-binding vegetation area in the southeastern edge of the Tengger Desert. We measured the 5 typical sand-fixing plants initial chemical composition of litter, soil microbial community, soil extracellular enzyme activity (EEAs) after 420-day of litter decomposition. The initial chemical composition of litter is an important factor in determining the K, and the initial content of Nitrogen (N), Carbon (C), and cellulose in litter (LitterPC2) increasing the abundance of positive taxa Ascomycota, Agromyces, and Preussia, while decreasing the abundance of negative taxa Chloroflexi, Gemmatimonadota, Chytridiomycota and Aspergillus, thereby collectively enhancing the activity of nitrogen cycling enzymes and oxidase, ultimately promoting K. The lignin, lignin/N, and C/N (LitterPC1) enhance K through nitrogen cycling enzymes stimulating oxidase activity, but reduce microbial biomass carbon (MBC)/ microbial biomass nitrogen (MBN) further inhibit the activity of enzyme C/N, thereby inhibiting decomposition. Overall, the energy and nutrient of litter initial quality regulate K by influencing the microbial keystone taxa and EEAs, which provides reference for species selection and reasonable collocation of artificial sand-binding vegetation in sandy area and also provide a scientific foundation for future management and stability maintenance of artificial vegetation.