SPP 2089 - Modelling self-organisation in the rhizosphere

All resources plants acquire from soil have to pass through the rhizosphere, i.e., that part of the soil in the vicinity of the roots that is influenced by root activities. This results in particular in radial gradients between root surface and bulk soil which are additionally shaped by the interplay of several interacting components (soil, roots, microorganisms, chemicals). Within the SPP 2089, the arising spatiotemporal patterns are approached through the concept of self-organisation. The overall objective of our project is to use multiscale modelling to study the interplay between root architecture development and gradients of various rhizosphere components simultaneously. Regarding the roots, multiscale means that the 1D radially symmetric single root model is solved for each individual root segment at a much higher spatial resolution than flow and transport on the whole root system scale. In this way, small-scale rhizosphere gradients can be captured at reasonable computational cost. For the case when it is necessary to represent the soil structure in the rhizosphere explicitly rather than by a Darcy scale approach, we develop a pore network model for the rhizosphere that is coupled to the bulk soil represented by the Darcy scale. This is our multiscale approach from the point of view of the soil. We will implement our models using the root architecture model CRootBox and DuMu^x, a simulator for flow and transport modelling in porous media. The models will be parameterised and evaluated based on experimental data acquired by different collaborating projects, including structural data on both root architecture and soil, data on plant water relations, exudates and nutrients as well as microbes in the rhizosphere. Our model results will contribute to the understanding of the rhizosphere as a self-organised system. In particular, we aim to predict parameter regimes in which different patterns represent stable, resilient systems.

Prof. Dr.-Ing. Rainer Helmig

Katharina Heck (M.Sc.)

Prof. Dr. Andrea Schnepf
Forschungszentrum Jülich GmbH
Institut für Bio- und Geowissenschaften
Agrosphäre (IBG-3)

09/2018 - 08/2021