AimsTree species mixing is an essential measure used to increase soil carbon (C) sinks and enhance nutrient cycling, while enzyme catalysis is the rate-limiting step of soil C mineralization and nutrient release. The study aimed to determine how mixing affects soil C and nitrogen (N) hydrolases kinetics in subtropical plantations.MethodsThe topsoil (0-15 cm) and subsoil (45-60 cm) from two monoculture coniferous plantations and two mixed plantations formed by replanting broad-leaved trees in the two coniferous plantations were collected to analyze the maximum activity (V-max), half-saturation constant (K-m) and catalytic efficiency (V-max/K-m) of four hydrolases involved in C (& beta;-glucosidase, BG; cellobioside, CB) and N (& beta;-N-acetylglucosaminidase, NAG; leucine aminopeptidase, LAP) cycling.ResultsMixing decreased the V-max of BG but increased the V-max of NAG in the topsoil, indicating the differential response of C and N enzyme activities to mixing. The K-m of NAG and LAP increased, while the V-max/K-m of CB and NAG decreased after mixing in the topsoil. Mixing decreased the V-max of CB and NAG and the V-max/K-m of BG and CB in the subsoil. The V-max/K-m values of C and N hydrolases were negatively correlated with SOC, total N and mineral N and positively correlated with the aromatic/aliphatic compound ratio, which illustrated that the hydrolases kinetics were mediated by changes in soil quality.ConclusionMixing decreased the catalytic efficiency of soil C and N hydrolases in subtropical plantations, although the mixing effect on soil hydrolase kinetic parameters depended on the enzyme type and soil depth.