Collaborative Research: Root Induced Changes of Soil Physical Properties Using Synchrotron X-ray Microtomography (CMT) and Micromechanical Simulations

根际是紧邻植物根部的土壤带，在为植物提供水分和养分方面发挥着突出的作用。然而，令人惊讶的是，人们对根际物理特性及其如何影响根的生长、水分和养分吸收知之甚少。缺乏必要的非侵入性和非破坏性成像技术来观察在未受干扰的土壤中生长的活根，这是造成这一缺点的主要原因。同步辐射X射线显微断层成像(CMT)的最新进展为直接观察活根周围的土壤物理性质提供了可能。这项研究的目的是通过(1)使用CMT来可视化根-土壤结构的物理相互作用，(2)使用计算机模型来模拟根诱导的根际结构变化，使用微观力学方法，以及(3)基于CMT成像和逆模型来估计根际水力性质的变化，如保水性和导水率，来量化根际物理性质。本研究试图为根际物理性质对活体植物吸收水分和养分的作用提供变革性的见解。它是更好地理解植物在土壤-大气界面的临界区中的作用的垫脚石。该项目跨越了生物学、土壤物理学和土壤力学的学科界限，为地表径流、土壤压实和侵蚀、农业生产力损失、土地开垦和土壤-植物相互作用原理提供了新的见解。将通过该项目培训博士生和博士后助理。

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.