Grassland soil carbon sequestration: Current understanding, challenges, and solutions

Abstract

Grasslands store approximately one third of the global terrestrial carbon stocks and can act as an important soil carbon sink. Recent studies show that plant diversity increases soil organic carbon (SOC) storage by elevating carbon inputs to belowground biomass and promoting microbial necromass contribution to SOC storage. Climate change affects grassland SOC storage by modifying the processes of plant carbon inputs and microbial catabolism and anabolism. Improved grazing management and biodiversity restoration can provide low-cost and/or high-carbon-gain options for natural climate solutions in global grasslands. The achievable SOC sequestration potential in global grasslands is 2.3 to 7.3 billion tons of carbon dioxide equivalents per year (CO₂e year^-1) for biodiversity restoration, 148 to 699 megatons of CO₂e year^-1 for improved grazing management, and 147 megatons of CO₂e year^-1 for sown legumes in pasturelands.