Soil microbiome interventions for carbon sequestration and climate mitigation

Mitigating climate change in soil ecosystems involves complex plant and microbial processes regulating carbon pools and flows. Here, we advocate for the use of soil microbiome interventions to help increase soil carbon stocks and curb greenhouse gas emissions from managed soils. Direct interventions include the introduction of microbial strains, consortia, phage, and soil transplants, whereas indirect interventions include managing soil conditions or additives to modulate community composition or its activities. Approaches to increase soil carbon stocks using microbially catalyzed processes include increasing carbon inputs from plants, promoting soil organic matter (SOM) formation, and reducing SOM turnover and production of diverse greenhouse gases. Marginal or degraded soils may provide the greatest opportunities for enhancing global soil carbon stocks. Among the many knowledge gaps in this field, crucial gaps include the processes influencing the transformation of plant-derived soil carbon inputs into SOM and the identity of the microbes and microbial activities impacting this transformation. As a critical step forward, we encourage broadening the current widespread screening of potentially beneficial soil microorganisms to encompass functions relevant to stimulating soil carbon stocks. Moreover, in developing these interventions, we must consider the potential ecological ramifications and uncertainties, such as incurred by the widespread introduction of homogenous inoculants and consortia, and the need for site-specificity given the extreme variation among soil habitats. Incentivization and implementation at large spatial scales could effectively harness increases in soil carbon stocks, helping to mitigate the impacts of climate change.

G.A.B. acknowledges support from the U.S. Department of Agriculture-National Institute of Food and Agriculture Hatch Project IOW04108. J.R.V.D.M. wishes to acknowledge funding from the Swiss National Centre in Competence Research NCCR Microbiomes (No. 51NF40_180575 and 51NF40_ 225148).

The authors are members of the Soil Microbiome Consortium for Climate Mitigation ("Soil Stars"), a group of scientists united to building a knowledgebase to develop and promote microbial solutions and communication strategies that can be deployed to solve complex problems at the nexus of agriculture, environmental sustainability, and climate resilience. Our work emphasizes the development of practical, scalable solutions that can be implemented globally to enhance soil health, optimize agricultural productivity, and reduce carbon footprints. This article was written on the basis of a 2024 discussion workshop, with authorship based on the voluntary participation of anyone in the consortium. More information on the Soil Microbiome Consortium for Climate Mitigation can be found at https://thesoilstars.com/.