ABSTRACT
The quantity of carbon in soils is substantial. It is larger than the total atmosphere and biosphere store, and may be equal to as much as a quarter of total of fossil fuel reserves. It is also subject to considerable change as land use changes. Wallace suggested that soil organic matter could be increased at a rate equal to present rate of carbon accumulation in the atmosphere, and so largely neutralise the greenhouse effect. This chapter examines this suggestion in terms of current knowledge of soil carbon levels, and the dynamics of soil organic matter changes. The most commonly used method for determination of soil carbon is by wet dichromate oxidation. The material which reaches the soil will be immediately subject to decomposition processes associated with the activities of soil fauna and flora. For any given soil and land management practice an equilibrium level of organic carbon will be attained if the practice is continued for a sufficiently long period.
