Heavy thinning temporally reduced soil carbon storage by intensifying soil microbial phosphorus limitation

• Published in: Plant and soil Vol. 484; no. 1-2; pp. 33 - 48
• Main Authors: Xue, Wenyan, Zhang, Weiwei, Chen, Yunming
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.03.2023; Springer; Springer Nature B.V
• Subjects: Agriculture; Analysis; Biomedical and Life Sciences; Carbon; Carbon content; Carbon sequestration; climate; Climate change; Climate change mitigation; Climate prediction; Ecology; Enzymatic activity; Enzyme activity; Forest ecosystems; Forest floor; forest litter; Forest management; Forest thinning; Forests; Influence; Life Sciences; Metabolism; Microorganisms; Nutrients; Organic matter; Organic phosphorus; Phosphorus; Plant debris; Plant Physiology; Plant Sciences; Review Article; Robinia pseudoacacia; soil carbon; Soil microbiology; Soil microorganisms; Soil organic matter; Soil Science & Conservation; Soils; Stoichiometry; Terrestrial ecosystems; Thinning; China; Carbon use efficiency; Forest thinning; Soil microbial metabolic limitation; Vector-threshold element ratio model; Ecoenzymatic activity and stoichiometry
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/s11104-022-05782-x

Purpose The decomposition of soil organic matter depends strongly on microbial metabolism, which presents one of the greatest uncertainties in predicting future climate and global carbon (C) dynamics. The study aimed to determine how forest thinning affects microbial metabolism in the short term and decipher the drivers. Method We determined the metabolic limitation of microbes by extracellular enzymatic stoichiometry and the microbial C use efficiency (CUE) by the biogeochemical-equilibrium model from 1 to 7 years after heavily thinning with debris removal from the forest floor in Robinia pseudoacacia plantations. The effects of thinning were compared with an untreated area. Results (1) thinning temporarily alleviated microbial relative C limitation whereas intensified P limitation in the short term, and no effects were observed 7 years after thinning. The availability and stoichiometric ratio of soil dissolved nutrients were factors most responsible for variations in microbial metabolic limitation. (2) microbial relative C and nutrient limitations exhibited negative correlations in thinned forests when C resources were sufficient, whereas positive correlations were detected in unthinned controls with insufficient C resources. Further analysis showed that the relationship was driven by ecoenzymatic stoichiometries. (3) CUE decreased by an average of 20.44% over 7 years after thinning. Partial least squares path modeling showed a trade-off between microbial P limitation and CUE, which was mediated by P-acquiring enzyme activity. Conclusion Soil microorganisms adapted to increased P limitation after high-intensity thinning by increasing investment into nutrient (particularly P) acquisitions via enzymes at the expense of lower metabolic efficient, which tended to reduce soil C storage. This study improves our understanding of microbial metabolic processes and C cycling after thinning in the short term, and provides important insights to climate change mitigation potential associated with managed forest ecosystems.