Carbon Storage Potential of Cultivated Soils Within Grassland Ecosystems Through a Benchmark Approach

ABSTRACT Although soil organic carbon sequestration is a primary focus for mitigating the global carbon deficit, actionable strategies are hampered by insufficient knowledge of real‐world sequestration capacities. We aim to evaluate the total organic carbon (TOC) stocks across several land use types and define the storage potential of recent cropland and pasture using the native soils as a reference. Using the “Soil Health Gap” concept, we derived a threshold of 50% and target values of 80% and 100% of the average TOC stock under native soils and evaluated the storage potential. The native TOC stocks (mean = 228.3 t/ha) were higher than co‐located recent cropland (171 t/ha) and comparable with pasture (221.5 t/ha). Using the set targets, cropland has a potential for TOC storage of 12–13 t/ha to reach 80% and 55–65 t/ha to reach the full pristine reference mean. According to the threshold value, all samples and averages of TOC were above it. We demonstrated that the land use type significantly alters TOC stocks and that cropland soils have the highest potential for TOC storage. A cropland conversion depletes TOC stocks by 25% relative to native grasslands due to intensive agricultural practices that accelerate decomposition and reduced litter inputs, while pastures maintain comparable levels through persistent rhizodeposition from perennial grasses. Whereas this approach is relatively easy to execute and can serve as a starting point for similar tasks, the selected targets and thresholds are arbitrary and highly sensitive, suggesting they were chosen to align with data availability and specific research objectives.