Synchrotron X-Ray Microtomography (XMT) – New Means to Quantify Root Induced Changes of Rhizosphere Physical Properties.

The rhizosphere, a thin layer of soil surrounding plant roots, plays a dynamic role in the hydrologic cycle by governing plant water and nutrient uptake. Study of rhizosphere soil structure formation due to mechanical processes has been limited by a lack of non-destructive techniques to quantify the dynamic nature of this region. In this chapter, we present recent developments in visualizing how growing roots modify their physical environment by moving soil particles, deforming aggregates and decreasing the amount of inter-aggregate pores while creating hydraulic pathways that connect neighboring soil aggregates using non-invasive, synchrotron X-ray Micro-Tomography (XMT). Image processing tools were applied for quantifying root-induced rhizosphere alterations from XMT grayscale images as well as to transform XMT images into Finite Element meshes, building a bridge from non-destructive rhizopshere visualization to micromechanical and hydraulic simulations.