Abstract: The study of soil microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), microbial biomass phosphorus (MBP) and their ecological stoichiometry along an elevation gradient is of great significance for understanding soil nutrient cycling and its relationship with environmental changes in subtropical mountains. In this study, soil samples were collected along an elevation gradient (350, 650, 950, 1050, 1850, and 2100 m) in the Wuyi Mountains to investigate elevational variations of the contents of MBC, MBN, MBP and the ratios of MBC/MBN, MBC/MBP, MBN/MBP. The results showed that soil MBC and MBN increased with elevation, while MBP and the ratios of MBC/MBN, MBC/MBP and MBN/MBP remained stable. MBC, MBN, and MBP were significantly positively correlated with the contents of soil total carbon (TC), total nitrogen (TN), available phosphorous (AP), dissolved organic carbon (DOC), dissolved organic nitrogen (DON), and soil water content (SWC). Soil MBC/MBN had a significantly positive correlation with soil DON, NO₃^--N, NH₄⁺-N contents and a significantly negative correlation with soil pH. Soil MBC/MBP was positively correlated with soil TN, DOC, TC, DON, SWC contents, and negatively correlated with soil C/N. Soil MBN/MBP was only positively correlated with soil pH. Results of redundancy analysis further indicated that soil TC content was the key factor influencing the contents and stoichiometry of MBC, MBN, and MBP.

Key words: Wuyi Mountains, elevation gradient, soil microbial biomass, ecological stoichiometry