Abstract:With the intensification of global warming, the rainfall pattern is also changing. Soil enzymes are the important participants in the chemical process of forest ecosystem and can quickly reflect the changes of soil environment. Therefore, studying the response of extracellular enzymes activities in subtropical soil to precipitation changes can effectively evaluate the impact of climate change on soil organic matter decomposition and transformation. In this study, the natural Castanopsis carlesii forest in Castanopsis kawakamii Nature Reserve of Sanming, Fujian Province was selected, and three treatments were set up, including control (CT), 30% of throughfall excluded (TE1) and 60% of throughfall excluded (TE2). In September 2020, soil samples of different soil layers (0—10, 10—20, 20—40, 40—60 cm) in each treatment were collected to study the effects of 9-year throughfall exclusion on soil enzymes activities. The results showed that the activities of β-glucosidase (βG), β-N-acetylglucosaminosidase (NAG) and acid phosphatase (AP) in the four soil layers decreased after throughfall exclusion. Compared with CT, the activities of AP, βG and NAG in 0—40 cm soil under TE2 treatment were significantly decreased (P <0.05), and the activities of AP in 40—60 cm soil under TE1 and TE2 treatments were also significantly decreased. With increasing soil layers, the activities of three extracellular enzymes decreased. Redundancy analysis (RDA) showed that soil moisture content (SWC), total nitrogen (TN) and soluble organic carbon (DOC) were the main factors regulating the activities of soil extracellular enzymes in 0—10 cm soil, while DOC and ammonium nitrogen (NH4+—N) in 10—20 cm, and soluble organic nitrogen (DON) and nitrate nitrogen (NO3-—N) in 20—40 cm. In 40—60 cm soil, the C∶P ratio mainly influenced the extracellular enzymes activities. In conclusion, the responses and regulatory factors of soil extracellular enzymes activities to the decrease of precipitation were different at different soil depths. The results of this study are helpful to further understand the mechanism of soil nutrient transformation and cycling in subtropical forests under global climate change.