Microbial biomass formation on root surfaces can be measured in plants growing in solution with or without an inert solid support. Carbon flow to the biomass can be measured by growing plants in solution or soil on a continuous source of 14C02 and the expected biomass formation predicted. The lack of correlation between measured and predicted biomass can be explained by oligotrophic growth of the micro-organisms. Microbial species within communities on the root surface can interact with each other, and a target for root inoculation is to elev%te the PFOllation of beneficial organisms within the community.
