Fran Hoyle

As soil organic carbon is central to the functioning of all soils, we require a more fundamental understanding of the climatic and management factors which influence its storage and persistence. The interest in carbon storage and sequestration has focused attention on changes in soil organic carbon across different regions, climates and management systems. The major components of soil organic carbon have different physical and chemical properties. A greater understanding of the quantities and composition of these different components is required to gain an insight into the relative contributions soil organic carbon can make to soil productivity. Whilst the texture and structure of the soil has an overriding influence on the capacity to store soil carbon, management options more often influence the actual soil organic carbon content. This chapter addresses the function of soil organic carbon in farming systems, including the role of specific fractions in key soil processes.