Project P7 "Measurement and Modeling of Plant Effects on Denitrification Using Innovative Methodology" focuses on the application of the novel plant-soil incubation chambers developed in DASIM I. The project will be based on the use of the DASIM I incubation system. This incubation system the identification and characterization of the importance of plant-microorganism interactions in the rhizosphere related to denitrifying nitrogen conversions and gas formation (NO, N2O, N2). In addition to the He (gas flow technique) used so far, where the chamber air is replaced by an N2-free mixture of He/O2 to allow measurements of N2 production, we will also use Raman spectroscopy for the first time, which should allow direct measurements of N2 production under "normal" atmospheric conditions (ca. 20% O2/ 80% N2) after further development of the technology. Our central hypothesis is that plant photosynthesis and denitrification in the rhizosphere are closely coupled, with root exudation as the determining factor. Experiments are conducted in the laboratory and on field lysimeters (total N2 balances) in close coordination with the other DASIM partners. The results of the own experimental work, as well as building on results of measurement and model approaches of the other involved research group members, will be used for the further development of the denitrification as well as the soil physics module of the biogeochemical model LandscapeDNDC. The model will be used to test the suitability of new DASIM model approaches and to scale measurement results from the micro to the plot scale.

The project is funded by DFG-Sachbeihilfe with the number FR2109/5-2; AOBJ:659825 and co-funded as a DFG research group.