P5 Processes determining nitrate dynamics in soil and the relationship to gaseous N production [funded by DFG]

Project staff:

Dr. agr. Sebastian Fiedler
Prof. PhD Christoph Müller
Prof. Dr. Nicole Wrage-Mönnig
Ms. Nicol Strasilla


Our project will focus on the cross validation of various isotopic methods to identify different pathways for gaseous N emissions and relate them to the underlying N transformation dynamics. The overall aim is to relate the bulk soil N dynamics to the N turnover in various soil fractions which are characterized by different denitrification activities. Thus it is hypothesized that denitrification is controlled by simultaneously occurring N transformations and can only accurately be predicted if the N transformations and gaseous N pathways in spatially distinct soil volumes are known. These distinct sites differ in microbial activity and are governed by abiotic (soil oxygen content) and distinct substrate relationships (available carbon content) (‘hot spot and hot moment’ concept). To address the inherent soil heterogeneity we propose a bottom-up approach with increasing complexity, starting by looking at the contribution of differently active homogenized soils with abandoned soil structure (Task 1), then identifying the activity of ‘hot spots’ in homogenous soils (Task 2) and finally testing the effect of hot spots on intact soils cores (i.e. with an without ‘hot spots’) (Task 3). Numerical tracing models will be developed which will also be used to analyse results of the central experiments as part of Tasks 2 and 3.

Publications and poster presentations: