Manan Bhan , Chetan Misher, Abhijeet Kulkarni, Ankila J. Hiremath, Abi Tamim Vanak

Semi-arid savanna grasslands (SG) in India deliver enormous benefits to people and nature but are currently undergoing large-scale degradation. Soil carbon stocks in degraded SGs vary in response to a host of anthropogenic driving factors including agricultural expansion and industrial development. Although there is increasing support for restoring grasslands by planting native grass species, its impact on soil carbon recovery is largely unknown. In this study, we undertake a plot-level investigation of soil and above-ground biomass carbon stocks to provide robust estimates of carbon densities across sites which have undergone restoration over the last 3 years and compare that with a no-intervention control using a space for time substitution framework. We find that SGs store significant amounts of carbon (12.74 - 22.11 tC/ha across 1-year to 3-year restoration sites respectively), with most of the carbon stored in soils (8.72 -12.54 tC/ha across 1-year to 3-year restoration sites respectively). The carbon stored progressively increases with the age of grass plantation. The 3-year site shows an increase of 34% carbon stock compared to the no-intervention control, and an increase of 30% and 21% in comparison to the 1-year and 2-year sites respectively. Our study demonstrates a robust approach to estimate soil carbon stocks in these ecosystems and highlights that effective conservation and restoration can enable SGs in India to act as natural carbon sinks at scale.