ABSTRACT Microbial carbon use efficiency (CUE) is a crucial indicator of soil carbon sequestration and transformation, and is significantly affected by soil moisture and temperature variations as well as anthropogenic nutrient management. However, systematic research on the mechanisms governing microbial CUE responses to the complex interactions between rainfall seasonality and forest management practices remains limited. Soil properties, carbon substrates, microbial communities, enzyme activity, and microbial carbon metabolism were quantified for both soil and litter samples in a mixed forest in dry and wet seasons using three forest management practices. Our findings indicate that microbial CUE was 31% (±7%) higher in the dry season than in the wet season and co‐occurred with higher soil nutrient availability and changes in carbon substrates composition. In the wet season, microbial CUE in structure‐based forest management (SBFM) plots was 13% higher than in unmanaged plots; however, in the dry season, it exceeded that of unmanaged plots by 4%. Soil carbon substrates (dry: path coefficient ( β ) = 0.85, p 0.05; wet: β = −0.41, p > 0.05) and the enzyme activity (dry: β = −0.61, p 0.05) had negative effects. However, microbial community (dry: β = 0.21, p > 0.05; wet: β = −0.02, p > 0.05) and soil properties (dry: β = 0.1, p > 0.05; wet: β = −0.07, p > 0.05) had negligible effects on microbial CUE. Under the SBFM treatment, both stable and labile carbon fractions were two times higher in the dry season than in the wet season. This study demonstrates that the dry season and SBFM enhance microbial CUE. Soil carbon substrates quantity and quality are the key predictors for microbial CUE. These results improve our understanding of the interactions among carbon dynamics, microbial physiology, and science‐based forest management in a mixed forest.
Xie et al. (Thu,) studied this question.