Nature – Zhou et al. (2023): Soil carbon in tropical savannas mostly derived from grasses
Yong Zhou, Barbara Bomfim, William J. Bond, Thomas W. Boutton, Madelon F. Case, Corli Coetsee, Andrew B. Davies, Edmund C. February, Emma F. Gray, Lucas C. R. Silva, Jamie L. Wright, A. Carla Staver IN: Nature Geoscience, 16, https://doi.org/10.1038/s41561-023-01232-0
Tropical savannas have been increasingly targeted for carbon sequestration by afforestation, assuming large gains in soil organic carbon (SOC) with increasing tree cover. Because savanna SOC is also derived from grasses, this assumption may not reflect real changes in SOC under afforestation. However, the exact contribution of grasses to SOC and the changes in SOC with increasing tree cover remain poorly understood. Here the authors combine a case study from Kruger National Park, South Africa, with data synthesized from tropical savannas globally to show that grass-derived carbon constitutes more than half of total SOC to a soil depth of 1 m, even in soils directly under trees.