The soil microbial biomass acts as the transformation agent of the organic matter in soil. As
such, the biomass is both a source and sink of the nutrients C, N, P and S contained in the
organic matter. It is the center of the majority of biological activity in soil. To properly
understand biological activity in soil one must therefore, have knowledge of the microbial
biomass. Investigating the flow of C and N in the soil, from newly deposited plant or other