FOR 2337:  Denitrification in Agricultural Soils: Integrated Control and Modelling at Various Scales (DASIM)

• Subject Area: Agriculture, Forestry and Veterinary Medicine
• Term: since 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 270261188

Denitrification, the process of nitrate reduction allowing microbes to sustain respiration under anaerobic conditions, is the key process returning reactive nitrogen as N2 to the atmosphere. The different reaction steps (NO3-, NO2-, NO-, N2O-, N2) are enzymatically mediated by a broad range of prokaryotes and some eukaryotes. Actively denitrifying communities in soil show distinct regulatory phenotypes (DRP) with characteristic controls on the single reaction steps and end-products. It is unresolved whether DRPs are anchored in the taxonomic composition of denitrifier communities and how environmental conditions shape them. Despite being intensively studied for more than 100 years, denitrification rates and emissions of its gaseous products can still not be satisfactorily predicted. While the impact of single environmental parameters is well understood, the complexity of the process itself with its intricate cellular regulation in response to highly variable factors in the soil matrix prevents robust prediction of gaseous emissions. Key parameters in soil are pO2, organic matter content and quality, pH and the microbial community structure, which in turn are affected by the soil structure, chemistry and soil-plant interactions. Here, we aim at the quantitative prediction of denitrification rates as a function of microscale soil structure, organic matter quality, DRPs and atmospheric boundary conditions. Combining state-of-the-art experimental and analytical tools (X-ray µCT, 15N tracing, NanoSIMS, microsensors, advanced flux detection, NMR spectroscopy, and molecular methods including next generation sequencing of functional gene transcripts), we will study denitrification processes at unprecedented spatial and temporal resolution. Improved numerical methods and computational power will allow to integrate results from the different groups and to develop denitrification models ranging from the microscale (phase 1) to the field/plot scale (phase 2).

• DFG Programme: Research Units

Projects

• Coordination Funds (Applicant Müller, Christoph )
• Crop plant root effects on the soil environment for denitrification in agricultural soils (Applicant Dittert, Klaus )
• Denitrification in relation to soil nitrite and nitrate dynamics – towards source differentiation in undisturbed soil (Applicants Müller, Christoph ;  Wrage-Mönnig, Nicole )
• Experimental exploration of denitrification in multiscale porous media and soil (Applicants Schlüter, Steffen ;  Vogel, Hans-Jörg )
• From single fractions to undisturbed soil: Role of soil organic matter in denitrification (Applicants Böttcher, Jürgen ;  Mikutta, Robert )
• Measuring and modelling of plant effects on denitrification using innovative techniques (Applicants Butterbach-Bahl, Klaus ;  Frosch, Torsten )
• Measuring N2 and N2O fluxes and related processes at high sensitivity and resolution in the field using advanced stable isotopic tools as a basis for model evaluation (Applicant Well, Reinhard )
• Multiple Scale Simulation of Denitrification (Applicant Ippisch, Olaf )
• Regulation, ecophysiology, and kinetic parameters of uncultured N-gas flux associated anaerobic microbial communities in agricultural soils: Towards a microscale spatial resolution (Applicant Horn, Marcus A. )

• Spokesperson: Professor Dr. Christoph Müller