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FOR 2337: Denitrification in Agricultural Soils: Integrated Control and Modelling at Various Scales (DASIM)
Collaborative Project
Project code:
FOR 2337
Contract period:
01.06.2016
- 31.05.2019
Coordinating institution:
Department of Plant Ecology
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).
Collaborative Projects
Subprojects
Leading institution:
Department of Plant Ecology
Research projects
- Soil incubations for model validation data sets and experiments to quantify the anaerobic soil volume fraction – Subproject P6 of the research unit 'Denitrification in Agricultural Soils: Integrated control and Modelling at various scales'
- Biogeochemistry of denitrification from plant-soil mesocosm studies to biogeochemical modelling at the ecosystem level
- Relevance of functional soil organic matter fractions for kinetics and spatiotemporal patterns of denitrification
- High-resolution Simulation of Denitrification
- Experimental exploration of denitrification in multiscale porous media and soil
- Regulation, ecophysiology, and kinetic parameters of uncultured N-gas flux associated anaerobic microbial communities in agricultural soils
- Crop plant root effects on the soil environment for denitrification in agricultural soils
- Denitrification in Agricultural Soils: Integrated control and Modelling at various scales. Subproject 5: Processes determining nitrate dynamics in soil and the relationship to gaseous N production