ABSTRACT
Managing microbial metabolism by manipulating carbon (C) inputs to minimize the rate of C mineralization may have potential for increasing C storage in soil. The chapter argues that the timing of glucose C addition determines the metabolic state of the microbial biomass. It suggests that the metabolic state of the microbial biomass determines the potential for C storage in soil by controlling the rate of mineralization of carbonaceous substrates and by influencing the spatial distribution of added C within soil size fractions. The experimental data support the hypothesis of distinct physiological responses to different rates of substrate infusion. First, differences between treatments were evident in kinetic analysis of C mineralization. In the pulsed treatment, mineralization was best described by a combination of two classes of kinetics: Michaelis-Menten and first-order. The majority of the C in the daily treatment was unaccounted for in the aggregate fractions and was thought to be associated with the <53 µm fraction.
