Organic-rich agricultural soils are significant sources of biogenic CO₂ emissions. This study investigates the relationship between residual organic carbon (OC) content and CO₂ emission rates. A laboratory incubation experiment showed that area-scaled CO₂ emissions from topsoils with >6% OC are not controlled by OC content or density. Current national greenhouse gas inventories may underestimate CO₂ emissions from soils with 6-12% OC by up to 40%, as demonstrated for Denmark. The study concludes that global underestimation likely occurs in countries with substantial areas of transitioning organic soils, highlighting the need for refined emission estimates for accurate national inventories and climate benefit assessments of soil rewetting initiatives.

Zhi Liang, Cecilie Hermansen, Peter L. Weber, Charles Pesch, Mogens H. Greve, Lis W. de Jonge, Maarit Mäenpää, Jens Leifeld, Lars Elsgaard