MODELS OF THE RHIZOSPHERE .2. A QUASI 3-DIMENSIONAL SIMULATION OF THE MICROBIAL-POPULATION DYNAMICS AROUND A GROWING ROOT RELEASING SOLUBLE EXUDATES

A mathematical model is outlined which is capable of simulating the radial and vertical distribution of soluble carbon, and of microbial biomass and necromass around a root growing through the soil. An alternating-direction implicit finite difference method is used to simulate the movement of soluble C by diffusion and convection in the rhizosphere cylinder surrounding the root. Results are presented which suggest that microbial populations in the rhizosphere of a growing root may vary considerably with distance along the root with the precise distribution of soluble C and biomass depending on the pattern of exudate release along the root length.