The Science

Soil organic matter (SOM) sustains terrestrial ecosystems, provides food and fiber, and retains the largest pool of actively cycling carbon. Over 75% of the soil organic carbon (SOC) in the top meter of soil is directly affected by human land-use practices. Large areas with and without intentional management are also being subjected to rapid climate changes, making many reservoirs of SOC in soil vulnerable to losses by decomposition or disturbance.

To quantify potential losses of SOC or its sequestration at field, regional, and global scales, members of the International Soil Carbon Network (ISCN) posit that improvements in scientific data, modeling, and communication are necessary. They also suggest that their network could be a platform for integrating the two scientific communities dominating SOM research: one focused on soil science and soil health and the other focused on the terrestrial carbon cycle and biogeochemistry. Together, these science communities have an opportunity to combine and transform knowledge, databases, and mathematical frameworks for the benefit of environmental health and humanity.

The Impact

SOM and its main constituent, SOC, interact with several aspects of the Earth system and its services to society, including food, fiber, water, energy, cycling of carbon and nutrients, and biodiversity. It is critical that the scientific community expand its understanding of SOM and SOC so that it can improve the state of soil and ecological sustainability, as well as contribute to climate change mitigation.

Summary

At the global scale, SOM is one of the largest actively cycling carbon reservoirs, and direct human activities (growing crops, grazing, and forestry practices) impact over 70% of carbon stocks in the upper meter of soil. The distribution of soils in managed lands follows the distribution of human land use. Overlaying the estimated SOC stocks with human land-use data shows that the majority of near-surface SOC stocks are directly affected by human activities today.

One global initiative to reduce atmospheric carbon dioxide (CO₂) through soil carbon sequestration has demonstrated that many soils in managed systems could offer an opportunity for climate regulation. And if these gains are applied across all land management plans, there is an opportunity to offset carbon emissions from permafrost, or from the combined projected emissions from land-use change and agricultural management.

The ISCN posits that there is a need and an opportunity for the scientific community to (1) better identify datasets to characterize ecosystem and landscape properties, processes, and the mechanisms that dictate SOC storage and stabilization and their vulnerabilities to change; (2) identify, rescue, and disseminate existing datasets; (3) develop platforms for sharing data, models, and management practices for SOC science; and (4) improve the connection between the research communities related to the global carbon cycle and to soil management.

Principal Investigator

Ben Bond-Lamberty
Pacific Northwest National Laboratory
BondLamberty@pnnl.gov

Program Manager

Daniel Stover
U.S. Department of Energy, Biological and Environmental Research (SC-33)
Environmental System Science
daniel.stover@science.doe.gov

Funding

BBL was supported by the Terrestrial Ecosystem Sciences program of the Office of Biological and Environmental Research (BER), within the U.S. Department of Energy (DOE) Office of Science. KTB was supported by the Linus Pauling Distinguished Postdoctoral Fellowship program at Pacific Northwest National Laboratory.

References