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Soil microflora influence plant growth and health both beneficially and adversely. The microorganisms used as biofertilisers stimulate plant growth response by providing necessary nutrients as a result of their colonisation of the rhizosphere (Azotob acter, Azospirillum, phosphate-solubilising bacteria and cyanobacteria) or by symbiotic association (Rhizobium, mycorrhizae fungi and Frankia). They may also regulate the physiological processes in the ecosystems by involvement in the decomposition of organic matter, fixation of atmospheric nitrogen, secretion of growth-promoting substances, increase in the availability of mineral nutrients, immobilisation of these assimilable nutrients and protection of plants from pathogens (Mukerji et al. 1998). Thus, rhizosphere effects through microbial activities, modify the plants by providing plant growth substances and increasing the availability of nutrients at the root …