Humus is an important indicator of soil quality and soil organic carbon (SOC) sequestration is a cost-effective measure to reduce the climatic impact of food production systems. The national soil-monitoring program (SMP) show an upward trend in SOC during the past 20 years, mostly attributed to an increased proportion of forages. This analysis only considered the topsoil but our results are also indicating changes of SOC in the subsoil, which implies the effects of management are under-estimated. This project determines whole-soil profile SOC stocks in long-term field experiments, focusing on forage-based rotations. We are also harmonizing SOC data from the national SMP with that of the Ministry of Agriculture and large databases from farmers’ routine soil analysis. Results are integrated in extension service tools including the ICBM SOC model, used for estimating the climatic footprint of agricultural products, and support the 4 per mille initiative and Swedish GHG reporting system.