Project Details
Projekt
Micromechanics of root growth and physical habitat properties in the rhizosphere
Applicant
Professor Dr. Stephan Peth
Subject Area
Soil Sciences
Term
since 2018
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 403627636
The rhizosphere forms a self-organised system with a multitude of physical, biological, and chemical interactions. Resulting from this interplay, properties emerge that increase the resilience of plant against limiting environmental conditions such as drought or mechanical soil impedence. In the rhizosphere, micro-mechanical properties play an important role but have not been intensely studied in connection with soil plant-interactions (eg. mucilage exsudation). These properties are crucial for the temporal and spatial development of soil structure, thus affecting – combined with biological processes – soil functions and plant development, which in turn alter soil structure. Building on the work of phase I we are now investigating the development of mechanical properties in the field and under controlled laboratory conditions with a focus on mechanical processes in relation to root development and soil structure formation including the physical characterisation of pore scale microbial habitats. To this end, we will take undisturbed soil samples and perform in-situ measurements. In the laboratory, we will take a close look at penetration resistance and its effect on the formation of the root system. Another aspect we will investigate is the pore space development during root decomposition and related changes in aggregate characteristics. To characterize the microbial habitat, we will examine the dynamics of redox potentials and local oxygen concentrations, as well as investigate aggregates using imaging and mechanical techniques. Soil mechanical properties will be measured oedometers, a laboratory vane probe, a material testing machine and a field micro penetrometer which will be newly developed. Results will be incorporated into the modelling approaches of project partners (cooperation with FZ Jülich). Furthermore, we will relate these data to root length densities and radii in cooperation with the UFZ Halle. As imaging techniques, we will apply X-ray computed tomography and quantitative image analysis with ToolIP. O2-concentrations and redox potentials will be measured in-situ with microsensors. The data collected are used to validate a model for effective diffusion coefficients (cooperation with the University of Erlangen Nuremberg). For our aggregate stability measurements, we will use a wet sieving approach and a recently developed dry-crushing method. In a cooperation with the Thünen-Institute we will investigate microstructure and stability of soil aggregates and characterize the physical habitat conditions and their relation to microbial diversity.
DFG Programme
Priority Programmes
Co-Investigator
Dr. Daniel Uteau Puschmann
