ABSTRACT
This chapter discusses the significance of utilizing microbial biomass values for investigating nutrient cycling in disturbed and nondisturbed ecosystems. Most biomass estimations are from temperate zone soils under agricultural cultivation, grassland, or forest. The estimates of pool sizes for microbial biomass C, N, P, and S suggest that these pools are large enough to have significant impacts on plant nutrient availability. Mineralization of plant nutrients from soil organic matter is a major function of the soil microbial biomass. Crop rotations affecting microbial biomass would make it possible to manage residues and rotations for the benefit of each crop. For soils, microbial biomass measurements may provide the information needed for ecosystem-level monitoring for initial disturbance and recovery. The role of microbial biomass in global nutrient cycles is well established, as significant N, P, and S transfers occur in terrestrial ecosystems.
