Energetic eco-physiology of the soil microbiota in two landscapes of southern and northern Germany

Abstract

Interactions between microbial communities and organic matter were analyzed for soils from the project regions ’Ecosystem Research in the Agricultural Landscape/FAM, Munich’ in southern Germany and ’Ecosystem Research in the Bornhoved Lake district’ from northern Germany using ratios between microbial biomass content (Cmic), microbial metabolic quotient (qCO2) and organic carbon content (Corg). In the agricultural soils in southern Germany, the qCO2/Corg ratio differed significantly with respect to agricultural management in contrast to ecophysiological Cmic/Corg ratio. In addition, Cmic/Corg ratio decreased from 39 to 21 mg Cmic g—1 Corg and qCO2/Corg ratio increased from 72 to 180 mg CO2-C g—1 Cmic h—1 (g Corg g—1 soil)—1 with increasing soil depth. For the upper soil horizons from the landscape in northern Germany the two quotients differed significantly with reference to land use showing highest microbial colonization under grassland and lowest under beech forest. In contrast, C use efficiency was lowest in arable field under maize monoculture and highest in a wet grassland having a high organic C content.