The distribution of the different ecologic micro organism groups in the soil, for the cultivated terrains, depends on the different types of fertilisers (mineral or organic) but, in great measure, also on the species of cultivated plants.
In the measure that the composition of the micro flora in the soil has a considerable influence on growth and development of the plants (contributing at fertilizing the soil) in the same measure the plants also constitute an especially important factor in the life of micro organisms, influencing their quantitative and qualitative composition. Their role manifests visible in the course of their life (through the radicular system), as well as after harvesting the plants.
Taking account of the major influence that the composition of the radicular excreta could have on the micro organism distribution in the soil, the current research studied the spectre modification of some ecophysiologycal micro organism groups involved in the nitrogen and carbon circulation in nature (ammonifying, denitrifying, nitrifying micro organism, free fixators, aerobes and type N anaerobes and cellulosolytic aerobes) in the soil of a Secale cereale culture infected with strains that belong to another type of alkaloids different from Claviceps purpurea.
The proposed research is justified from the point of view of the anterior results that demonstrated the metabolism altering of the infected plants, considering this aspect as having influence on the radicular exudate composition and implicitly on the micro organism distribution in the soil belonging to different ecophysiologycal groups. | 
