Newly published research from Michigan State University shows how to accurately assess changes in soil carbon stocks. This calculation has significant implications for measuring the actual environmental benefits of agricultural practices and economic outcomes through emerging carbon markets.
The findings were. Published in scientific reportsNature Portfolio Magazine.
The project was managed Bruno BassoJohn Hanna Distinguished Professor in the Departments of Earth and Environmental Sciences and Plant, soil and microbiology scienceAlso WK Kellogg Biological Station.
His team included two members of his lab: Ames Fowler, a crop model research associate, and Neville Millar, a postdoctoral fellow. Will Brinton, founder and chief science officer of Wood’s End Laboratories in Maine, contributed.
The importance of agriculture in providing the food, fiber and fuel to support a growing world population cannot be overstated. But challenges abound, with climate change among the most difficult to tackle. Farmers, scientists and corporations are exploring ways to make this important industry more sustainable.
Agriculture accounts for 23% of the Intergovernmental Panel on Climate Change’s 2022 estimates for policymakers. Considering the growth of agriculture such as cover crops and no-till, however, Basso said, this provides opportunities to use meaningful improvements.
“Agriculture is the main sector that affects soil and landscape management, so improving agricultural management and policy is important to reduce greenhouse gas emissions,” he said. “This includes carbon sequestration in the soil, which many private industries and non-profit organizations are beginning to value.”
Soil can hold large amounts of carbon — more than the atmosphere and combined vegetation — helping the environment and, more recently, farmers’ bottom lines. Soil carbon incentives and markets have led private companies and non-profit organizations to charge farmers for sequestering carbon in the soil. But many farmers are skeptical.
The cost of soil sampling, remote sensing image analysis, modeling, and other carbon stock assessment methods currently makes its economic utility difficult. According to Baso, farmers are definitely looking for changes in soil carbon stock.
In addition, many countries around the world use changes in soil carbon stock to determine the success of agricultural policy shifts, but the same problems of cost and unreliable data persist.
One of the main challenges, Basso says, is adopting a systematic way to accurately measure changes in soil carbon.
“Science provides an important perspective in the trade of carbon markets and agricultural policy,” Basso said. “We will not develop a true understanding of the effectiveness of our sustainability efforts unless carbon stocks are properly and accurately measured.”
To that end, Basso and his team examined the global standard for assessing changes in soil carbon stock, which involves repeated, constant-depth soil sampling at a site of at least 30 cm.
Researchers used approximate 30-centimeter samples taken at three time points to predict changes in soil organic carbon, with differences in bulk density accounting for constant depth sampling error.
As more carbon is stored in the soil, the mass decreases because more air is available. If carbon is removed, less air is added, making the bulk density higher. Current soil organic carbon calculations do not account for this mass density.
“This new approach closes the gap for decades of on-farm research that has seen bulk density go up or down depending on management,” said Will Brinton. Author of the study. “This work provides a direct, field- and laboratory-friendly answer to correcting the known errors of the past.”
Equivalent Soil Weight or ESM In a so-called calibration calculation, Basso and his team show that current methods of measuring soil carbon stock can be used as long as the ESM is not implemented. This means changing soil depth parameters based on changes in bulk density.
For example, where bulk density decreases with time, the sample depth should be increased. The ESM calculation helps scientists determine the required depth of the new sample.
Ames Fowler and Neville Millar, co-authors of the study, added: “It will be useful in carbon market regulation, including calculation, reporting and verification platforms and protocols. It helps to encourage farmers who are reluctant to adopt more costly conservation management methods. “
The project is supported in part by the US Department of Agriculture’s National Institute of Food and Agriculture, the Great Lakes Bioenergy Research Center, and the US Office of Science and Energy.
This story was originally published by College of Agriculture and Natural Resources.