Measuring and modelling of plant effects on denitrification using innovative techniques

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The project P7 „Measuring and modelling of plant effects on denitrification using innovative techniques” will use the newly, in DASIM Phase I developed plant-soil-incubation chamber for further characterizing the significance of rhizosphere plant-micro-organism interactions for denitrification and N gas production via denitrification (NO, N2O, N2) in soils. In addition to the so far used Helium (He) gas flow technique, which is based on the headspace gas exchange with a N2 free atmosphere mixture of He and O2 to allow for N2 production, we will for the first time test the suitability of advanced Raman spectroscopy for N2 production measurements under “standard” atmospheric composition conditions (ca. 20% O2/ 80% N2). Though this will require further developments of the photonic technology, we are very positive that this new technological approach will offer new insights and a scientific breakthrough in our capability to measure soil-plant denitrification dynamics in soils directly.We hypothesize that plant photosynthesis and rhizosphere denitrification are closely coupled via root exudation, with relationships not being quantified yet. Laboratory and field-lysimeter experiments (total N balance of large intact soil cores under field condition) will be executed in close cooperation with all DASIM partners. Results of own experiments as well as experimental and modelling results of DASIM partners will be used for the further development of the denitrification and soil hydrology/physics submodules of the biogeochemical model LandscapeDNDC. This model will be used for testing various currently developed DASIM model approaches and for scaling resul