Effects of transforming multiple ecosystem types to tree plantations on soil microbial biomass carbon, nitrogen, phosphorus and their ratios in China

Tree plantations (thereafter plantations) is considered to be one of the most common land use changes that may have significant effects on soil microbial biomass, but the broader patterns and underlying drivers remain unclear. Here, we quantified the effects of transforming shrublands, secondary forests, primary forests, grasslands, deserts, and croplands to plantations on the concentrations of soil microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), microbial biomass phosphorus (MBP) and their ratios (i.e., MBC: MBN, MBC:MNP and MBN:MBP) based on 2107 paired observations from 107 studies using meta-analysis across China. We found that (1) transforming grasslands into plantations significantly increased MBC, MBN, and MBP concentrations by 81.1, 75.3, and 65.4 %, respectively, while transforming primary forests to plantations significantly decreased soil MBC, MBN, and MBP concentrations by-29.2-34.7, and 50.6 %, respectively; (2) ecosystem transformation effects were seldom affected by plantation type, mycorrhizal association, plantation year, or soil depth; and (3) the impacts of climate, species richness, and soil properties on ecosystem transformation effects depended on former ecosystem type. Overall, our results clearly showed how ecosystem transformation affected soil MBC, MBN, MBP, and MBC:MBN, MBC:MBP, and MBN:MBP ratios, which plays a crucial role in nutrient cycling in ecosystems and evaluate sustainability of forest management.

Automated summary

This study quantified the effects of converting different types of ecosystems to tree plantations on soil microbial biomass in China. The results showed that converting grasslands to plantations increased soil microbial biomass, while converting primary forests to plantations decreased soil microbial biomass. The effects of ecosystem transformation were not significantly influenced by plantation type, mycorrhizal association, plantation year, or soil depth. The impacts of climate, species richness, and soil properties on ecosystem transformation effects depended on the former ecosystem type.