Carbon transformations and soil organic matter formation

Abstract Plants and soil microorganisms play a major role in the cycling of carbon (C) on Earth. This chapter describes the terrestrial C cycle and how the various components comprising plant and microbial residues are processed by soil microorganisms to produce microbial biomass, soil organic matter (SOM), and carbon dioxide. The nature and factors affecting the production of SOM are discussed, including recent research findings that challenge long-standing SOM paradigms. A method for determining microbial biomass in soils is also presented.