Carbon sequestration in soil

•Soil C sequestration can strengthen land-based C sinks and off-set anthropogenic emissions.•Among numerous co-benefits of soil C sequestration are advancing food security, increasing supply and quality of water, enhancing biodiversity, among others.•Critical level of soil organic C concentration in the root zone is 1.5–2.0% by weight.•Degraded and depleted soils of agroecosytems have a high C sink capacity.•Soil C sequestration is a cost-effective and a win–win option.

Soil carbon (C) sequestration implies transferring of atmospheric CO2 into soil of a land unit through its plants. Co-benefits of soil C sequestration include: advancing food and nutritional security, increasing renewability and quality of water, improving biodiversity, and strengthening elemental recycling. Threshold level of soil organic C (SOC) in the root zone is 1.5–2.0%. SOC is influenced by land use, soil management and farming systems. To 1-m depth, more than 50% total C pool is contained between 0.3 and 1 m depth. Soils of agroecosystems are strongly depleted of their SOC stock and are degraded. Restoring soil quality necessitates increasing SOC concentration by adopting best management practices (i.e., conservation agriculture) which create a positive C budget. French Government is proposing to COP-21 of UNFCCC in December 2015 that SOC concentration be increased globally at 4 per 1000 per year to mitigate climate change and advance food security.