Abstract: Aims Numerous simulation experiments have shown that increased atmospheric acid deposition could lead to the increase of phosphorus limitation of soil microbes. However, there is a lack of in-depth analysis of how acid deposition affects microbial element limitation around industrial acid emission sources, especially in areas with severe soil salinity-alkalinity. Methods Taking three power plants in the Ningdong Energy and Chemical Industry Base as the monitoring sites, this paper analyzed soil enzyme ecological stoichiometry and explored the microbial element limitation and its influencing factors around industrial acid emission sources. Important findings The results showed that the ranges of carbon-acquiring enzyme activity (C_E), nitrogen-acquiring enzyme activity (N_E), phosphorus-acquiring enzyme activity (P_E), lnC:N_E, lnC:P_E, and lnN:P_E were 3.31~59.92 nmol·g^⁻1, 4.24~125.95 nmol·g^⁻1, 3.62~189.46 nmol·g^⁻1, 0.48~1.47, 0.32~1.41, and 0.56~1.18. Nitrogen and sulfur deposition did not affect the enzyme vector length and angle (p > 0.05). Ca²⁺ and K⁺ deposition positively influenced the vector length (p < 0.05) by a direct approach or by indirect approaches, soil physiochemical properties (electrical conductivity, available phosphorus, Na⁺, Mg²⁺, etc.), plant traits (total phosphorus and N:P) and microbial characteristics (biomass carbon and nitrogen). Ca²⁺ and Na⁺ deposition positively influenced the vector angle (p < 0.01) by affecting soil physiochemical properties and plant traits. In summary, microbes are mainly limited by phosphorus in the study area; nitrogen and sulfur deposition does not alter microbial element limitation. In contrast, base cation deposition could enhance microbial carbon and phosphorus limitation by aggregating soil salt stress, reducing soil phosphorus availability, and triggering phosphorus competition between plants and microbes.

Key words: acid deposition, industrial acid emission sources, saline-alkali desert, soil enzyme ecological stoichiometry, microbial elemental limitation