1,446 publications from this institution
Stabilized soil organic carbon is the most persistent fraction of soil carbon and plays a key role in long-term climate mitigation, yet its global distribution remains poorly constrained. Here we integrate georeferenced soil profiles with a machine learning model to map stabilized soil carbon in the upper one meter of soils worldwide. Global stabilized soil carbon is estimated at 1304 petagrams of carbon, representing about half of total soil carbon and concentrated in wetlands and cold-temperate regions. Soil properties explain most of the spatial variation, whereas climate and management effects show threshold responses. We further define soil negative carbon potential, the proportion of stabilized carbon in total soil carbon, as an indicator of stabilization efficiency and mitigation potential. Increasing this metric is associated with lower greenhouse gas emissions and improved economic outcomes with minimal yield trade-offs. These results provide benchmarks for Earth system models and inform soil-based climate mitigation strategies. Stabilized soil organic carbon totals 1304 pentagrams carbon globally about half of total soil carbon concentrated in wetlands and cold regions shown by mapping upper one-meter soils using georeferenced soil profiles and high precision machine learning models.
Elucidating complex interactions between bacteria and fungi that determine microbial community structure, composition, and functions in soil, as well as regulate carbon (C) and nutrient fluxes, is crucial to understand biogeochemical cycles. Among the various interactions, competition for resources is the main factor determining the adaptation and niche differentiation between these two big microbial groups in soil. This is because C and energy limitations for microbial growth are a rule rather than an exception. Here, we review the C and energy demands of bacteria and fungi—the two major kingdoms in soil—the mechanisms of their competition for these and other resources, leading to niche differentiation, and the global change impacts on this competition. The normalized microbial utilization preference showed that bacteria are 1.4–5 times more efficient in the uptake of simple organic compounds as substrates, whereas fungi are 1.1–4.1 times more effective in utilizing complex compounds. Accordingly, bacteria strongly outcompete fungi for simple substrates, while fungi take advantage of complex compounds. Bacteria also compete with fungi for the products released during the degradation of complex substrates. Based on these specifics, we differentiated spatial, temporal, and chemical niches for these two groups in soil. The competition will increase under the main five global changes including elevated CO2, N deposition, soil acidification, global warming, and drought. Elevated CO2, N deposition, and warming increase bacterial dominance, whereas soil acidification and drought increase fungal competitiveness.
