Bacteria life-history strategies and the linkage of soil C-N-P stoichiometry to microbial resource limitation differed in karst and non-karst plantation forests in southwest China

Abstract

Soil microbial resource-acquisition strategies play a crucial role in soil nutrient cycling and the accumulation of soil organic carbon (SOC) in vegetation restoration. Despite the growing interest in soil microbial resource limitation, the impact of lithology on microbial resource limitation and its relationship with soil carbon–nitrogen-phosphorus (C-N-P) stoichiometry is not well understood. Therefore, we investigated the soil C-N-P and ecoenzymatic stoichiometry, bacterial life-history strategies, and microbial resource limitation in two common plantation forests (Pinus yunnanensis Franch. (PY) and Eucalyptus maideni F. Muell. (EM)) in karst and non-karst areas in southwest China. These areas are characterized by soils derived from limestone and clastic rock, respectively. The results showed that (1) soil nutrients, SOC concentrations and ecoenzymatic activities were significantly higher in karst plantation forests compared to non-karst, except for dissolved inorganic phosphorus; (2) soil microorganisms in both lithology were largely co-limited by C and P in EM plantation while the PY plantation soil in organic horizon primarily limited by P, which might be due to a much higher ratio of soil C:P and N:P; (3) lithology affects the associations between soil C-N-P stoichiometry and microbial resource limitation; (4) redundancy analysis showed that the ratio of C:N acquiring enzyme was a substantially predictor for microbial resource limitation in both karst and non-karst soils; (5) karst soils had a higher proportion of species affiliated with oligotrophs bacteria. Overall, these findings improve our knowledge of microbial resource limitation over limestone and clastic rock and its relationship with soil C-N-P and ecoenzymatic stoichiometry, as well as the lithology effects on bacteria life-history strategies.