Plant and Soil

, Volume 133, Issue 2, pp 187–199

Models of the rhizosphere

I. Microbial population dynamics around a root releasing soluble and insoluble carbon
  • P. R. Darrah

DOI: 10.1007/BF00009191

Cite this article as:
Darrah, P.R. Plant Soil (1991) 133: 187. doi:10.1007/BF00009191


A mathematical model has been developed which is capable of simulating the population dynamics of microbial biomass surrounding a root which is releasing soluble and insoluble carbon compounds into the soil. The model simulates the interconversions of C between different pools within the soil as well as the diffusion and mass flow of soluble carbon. Two main aspects of carbon release were examined: (i) a strategy where exudate was released uniformly over the root surface was compared to the case where exudation was confined to a small region behind the root tip; (ii) the situation in which all the C released was in soluble form was compared to the case of an approximately equal partition between soluble and insoluble forms. Substantial differences between the different simulations were found. It was shown that the maximum concentration and penetration of soluble exudates differed markedly between different simulations and the implications of this for micronutrient acquisition by phytosiderophores and for colonisation of the rhizosphere by root pathogens were discussed. The different simulations also predicted very different biomass distributions in the rhizosphere in both space and time.

Key words

insoluble carbon mathematical model population dynamics rhizosphere soluble carbon 

Copyright information

© Kluwer Academic Publishers 1991

Authors and Affiliations

  • P. R. Darrah
    • 1
  1. 1.Soil Science Laboratory, Department of Plant SciencesUniversity of OxfordOxfordUK