The rhizosphere, the zone of soil immediately surrounding plant roots, plays a prominent role in supplying plants with water and nutrients. However, surprisingly little is known about rhizosphere physical properties and how they affect root growth, water and nutrient uptake. The lack of non-invasive and non-destructive imaging techniques necessary to observe living roots growing in undisturbed soil have been a main reason for this shortcoming. Recent advances in synchrotron X-ray microtomography, or CMT, provide the potential to directly observe soil physical properties around living roots in-situ. The goal of this research is to quantify rhizosphere physical properties by (1) employing CMT to visualize physical root-soil structure interactions, (2) using computer models to simulate root-induced structural alterations to the rhizosphere using micro-mechanical approaches, and (3) estimating changes in rhizosphere hydraulic properties, such as water retention and hydraulic conductivity, based on CMT imaging and inverse modeling.
This research seeks to provide transformative insights into the role of rhizosphere physical properties for water and nutrient uptake by living plants. It serves as a stepping stone for better understanding the role of plants in the critical zone at the soil-atmosphere interface. The project cuts across disciplinary boundaries of biology, soil physics, and soil mechanics to offer new insights on surface runoff, soil compaction and erosion, losses to agricultural productivity, land reclamation, and principles of soil-plant interactions. Doctoral students and a post-Doctoral associate will be trained through this project.
