Abstract: Straw return and chemical fertilizer applications in the cultivated soils change the concentrations of soil carbon (C),nitrogen (N),phosphorus (P),sulfur (S) and their stoichiometry,which affect soil enzyme activity and soil fertility.To clarify how soil enzyme activity responds to changes in soil available C,N,P,and S concentration and their stoichiometry,a glucose and inorganic fertilizers (including N,P,and S) addition experiment was conducted to determine the activities of β-1,4-glucosidase (BG),cellobiohydrolase (CBH),β-N-acetylglucosaminidase (NAG),and acid phosphatase (AP) in the subtropical paddy soils.The results showed that,glucose addition significantly increased CHB,BG,NAG,and AP activities in paddy soils after 3 days of incubation.Irrespective of glucose addition,there was no significant change in soil enzyme activities across the nutrient addition levels after 3-day incubation.After 60 days of incubation,soil enzyme activities were lower in soils with glucose than that in soil without glucose under high nutrient addition level.Moreover,soil enzyme activities significantly decreased with the increase of nutrient addition levels in the presence of glucose addition after 60 days of incubation.By the end of incubation,the (BG+CBH)/NAG ratio increased with the nutrient addition level,implying that nutrient addition reduced microbial N limitation in paddy soils.However,the (BG+CBH)/AP ratio decreased with the nutrient addition level,indicating that microbial P limitation was intensified in paddy soil.Our results uncover the stoichiometric relationships between soil enzyme activity and carbon and nutrient elements,which would be of significance for optimizing farmland soil nutrient management and improving soil fertility.