Project Details
Projekt
Small scaled and dynamic analysis of microstructural rhizo- and drilosphere properties: porosity, physicochemistry and their role for root growth, nutrient storage and transport/support
Subject Area
Soil Sciences
Term
from 2014 to 2021
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 259987874
The research of this project is based on the former research unit FOR 1320 where the effect of different preceding crops and crop sequences on the development of characteristic biopore systems and their functional properties in the subsoil was investigated. Pore network architectures were quantified non-invasively using X-ray computed microtomography and image analysis. The results underline the importance of biopores for water and air supply by supporting deeper rooting. It was found that earthworm and root generated biopores were distinctly different at the microscale, especially at the interface between biopore and bulk soil (pore wall). Previously blocked pores e. g. regained continuity, whereas in other pores earthworm cast lined and/or blocked the pores or truncated lateral channels previously formed by secondary roots. To what extent the pore wall properties influence the transfer of air and water as well as nutrients between bulk soil and the pore through the rhizodrilosphere is still unknown. First measurements on microscale gas diffusion revealed that root-induced pores are more suitable for air transport than worm-induced pores due the large amount of lateral channels. On the other hand, worm-induced pores might result in hydrophobic pore walls due to the lining with root and/or worm exudates that will lead to more water-stable structures but also reduce lateral water transport. In this project a detailed analysis of the pore wall properties is envisaged in a combined approach (StrucDyn/Kassel, and RhizPhy/Kiel) including both the structure and micromorphology of the biopore network (StrucDyn) and the physicochemical, physical and chemical aspects of the pore wall (RhizPhy). StrucDyn will investigate non-invasively the architecture of single biopores including the morphologies of the pore wall and rhizodrilosphere pore space depending on the pore origin/colonization (worm or root) as well as due to biopore aging. Morphological image analysis and digital image correlation will be utilized to detected pore modifications. Pore wall properties such as actual hydrophobicity (repellency), the transferability of water (sorptivity, microinfiltration) and air (oxygen diffusion, redox potential) as well as micromechanical properties (micropenetration, rheomtry) will be determined by RhizPhy on both intact pore walls and root and worm exudates as well as biological model substances. The obtained data from StrucDyn and RhizPhy will be used to parameterize and further develop a root growth model (RootMod) in order to investigate the effect of microstructural and hydraulic/mechanical properties of the rhizodrilosphere on root development and water and nutrient uptake.
DFG Programme
Research Grants
Participating Person
Dr. Dörthe Holthusen
