Besides the earthworm, numerous small creatures and microorganisms inhabit the soil. The realm of microorganisms is still largely unexplored. Hence in 2012, the National Soil Monitoring Network NABO began to assess 30 selected NABO sites (Figure) on the microbiological and molecular levels. The collection of multiannual data sequences should generate site-characteristic values and their associated variability. On this basis, soil biological properties can be assessed and long-term trends evaluated more precisely.
Soil-dwelling organisms play a central role in many soil functions, such as biological nitrogen fixation, decomposition of organic material, food production and water filtration. The organisms are sensitive to environmental changes, and their reactions can be early indicators of undesirable conditions.
Classical microbiological parameters such as microbial biomass and basal respiration represent the sum of mircobial organisms or their activity. Of further interest is the presence of specifiable (groups of) organisms. The composition of fungal and bacterial communities can be determined with molecular gene analyses. These methods change rapidly and offer continuously expanding possibilities for research. For instance, the soil organisms, their diversity and their functions can be determined, once their DNA is 'decoded'.