Improving carbon sequestration estimation through accounting carbon stored in grassland soil

Based on international guidelines, the elaboration of national carbon (C) budgets in many countries has tended to set aside the capacity of grazing lands to sequester C as soil organic carbon (SOC). A widely applied simple method assumes a steady state for SOC stocks in grasslands and a long-term equilibrium between annual C gains and losses. This article presents a theoretical method based on the annual conversion of below-ground biomass into SOC to include the capacity of grazing-land soils to sequester C in greenhouse gases (GHG) calculations. Average figures from both methods can be combined with land-use/land-cover data to reassess the net C sequestration of the rural sector from a country. The results of said method were validated with empirical values based on peer-reviewed literature that provided annual data on SOC sequestration. This methodology offers important differences over pre-existing GHG landscape approach calculation methods: improves the estimation about the capacity of grazing-land soils to sequester C assuming these lands are not in a steady state and counts C gains when considering that grazing lands are managed at low livestock densities. (C) 2019 The Author(s). Published by Elsevier B.V.