Soil Organic Carbon: Pools and Predictors in Nordic Agricultural Soils, and Insights into SOM Fractionation Methodology

Soil organic carbon sustains soil functions essential to agriculture by fueling soil life, supporting soil structure, and retaining water for crops. A widely used framework divides soil organic carbon into two forms that are thought to play different roles in these functions. Most existing knowledge about these two forms comes from older, more weathered soils. In my PhD, I explored from several angles how this framework and its methods translate to young Nordic soils formed after the last ice age. I found that the framework did not fully capture the behavior of these soils. I also compared two laboratory methods used to study these forms and found that the more widely used method did not separate them cleanly, while the other performed better. Overall, the results highlight the need for caution when applying soil carbon frameworks and methods across regions, as they may not translate reliably across soil types.