Microbial community structure and activity in agricultural soils under different management

For the development of management strategies in sustainable agriculture it is necessary to describe and predict the role of soil microbes in different management systems. The classical approach uses the microbial biomass as the key parameter for the entire system. but for ecological purposes Ihe variability of biotic parameters in time and space has to be better described. Momvcr. the biomass active in the total soil profile or its most active zones should be used as a basis for the assessment of soil activity. The sum of adenylntes wns found to be more closely reluted to the microbiul biomuss thm was ATP, which however a p p r c d to be a better indicator for the niicrobial uctivity. Fany acids from phospholipids were highly comlntcd with the soil microbial biomass. The pattern of fatty acids from soils under diffcrcnt long-term management indicated a high potential to typify the microbial community in soils and special organism populations. To overcome llic problem, that only a small portion of Ihe soil inhabiting microbcs cm be cultivated, first steps to use scrolopical and genetical methods to directly identify or localize specific populations in the rhizosphere rire shown.