Fig. 4: Global soil mineralogical carbon capacity, mineral-associated carbon stocks, and potential for carbon accrual.
From: Global stocks and capacity of mineral-associated soil organic carbon
a Mineralogical carbon capacity (MOCmax; kg C m−2 soil), b mineral-associated organic carbon (MOC; kg C m−2 soil), and c percent mineralogical carbon saturation (%C saturation) in topsoil (0–30 cm) at 0.5° resolution, excluding tundra, peatlands, and deserts. MOCmax was estimated using our data-derived relationships with the amount and type of mineral. MOC was predicted using a random forest model trained on our observational dataset. %C saturation was calculated as MOC/MOCmax. Low %C saturation corresponds to a greater C deficit, and therefore highlights regions where targeted soil management could lead to higher C sequestration. d Carbon accrual in topsoil (t ha−1 yr−1; mean depth = 29 cm) as a function of %C saturation across sites, based on our global synthesis of studies that measured C accrual following management interventions (n = 103). Nonlinear fit depicts asymptotic regression model with shaded areas representing 10th and 90th quantiles.
