Food Security Through Better Soil Carbon Management

Abstract

Soils store and filter water, prevent flooding, support the production of fuel and fibre, provide habitat, help to create landscape and are a major carbon (C) store. They are, thus, an essential component of supporting, provisioning, regulating and cultural ecosystem services and determinants and constituents of well-being, providing security, the basic material for a good life, health and good social relations. However, calculations based on inherent land quality classes show that fertile soil (that is, soil free of constraints for agricultural production) irregularly covers no more than 12 % of the terrestrial land surface. More generally, soil fertility/quality is determined by the interactions between land management interventions by humans and the inherent physical, chemical and biological properties of a soil. Land and soil management based on the understanding of these interactions is one part of delivering food security. Even small changes in C content can have disproportionately large impacts on key soil properties. Practices to encourage maintenance of soil organic carbon (SOC) are important for ensuring sustainability of most if not all soil functions. This chapter considers the relationship between SOC and soil fertility and structure, ways of increasing SOC, some disadvantages of increasing SOC and two proposed ways of increasing SOC, fertility and sequestering C: the soil application of biochar and the cultivation of deeper rooting crops.