Remains of dead bacteria have far greater meaning for soils than previously assumed. Around 40 per cent of the microbial biomass is converted to organic soil components, write researchers from the Helmholtz Centre for Environmental Research (UFZ), the Technische Universität Dresden (Technical University of Dresden) , the University of Stockholm, the Max-Planck-Institut für Entwicklungsbiologie (Max Planck Institute for Developmental Biology) and the Leibniz-Universität Hannover (Leibniz University Hannover) in the professional journal Biogeochemistry.
Until now It was assumed that the organic components of the soil were comprised mostly of decomposed plant material which is directly converted to humic substances. In a laboratory experiment and in field testing the researchers have now refuted this thesis. Evidently the easily biologically degradable plant material is initially converted to microbial biomass which then provides the source material to soil organic matter.
Soil organic matter represent the largest fraction of terrestrially bound carbon in the biosphere. The compounds therefore play an important role not only for soil fertility and agricultural yields. They are also one of the key factors controlling the concentration of carbon dioxide in the atmosphere. Climatic change can therefore be slowed down or accelerated, according to the management of the soil resource.