SOIL ORGANIC-MATTER - DISTRIBUTION, GENESIS, AND MANAGEMENT TO REDUCEGREENHOUSE-GAS EMISSIONS

In this paper we describe the accumulation of soil organic matter (SOM ) during pedogenesis and the processes that can lead to the emission o f greenhouse gases (CO2, CH4, N2O) to the atmosphere via SOM decomposi tion and denitrification. We discuss the role of management on SOM acc umulation and loss, and the potential for controlling emission or coms umption of greenhouse gases by soils. We conclude that under current c limate conditions there are global scale opportunities to reduce green house gas emissions from soils and increase the indirect sequestration of greenhouse gases in soils through improved soil management.