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区域，在为植物提供水分和养分方面发挥着重要作用。然而，令人惊讶的是，人们对根际物理特性及其如何影响根系生长、水分和养分吸收知之甚少。 缺乏观察在未受干扰的土壤中生长的活根所需的非侵入性和非破坏性成像技术是造成这一缺陷的主要原因。 同步加速器 X 射线显微断层扫描 (CMT) 的最新进展为直接原位观察活根周围的土壤物理特性提供了可能。 本研究的目标是通过以下方式量化根际物理特性：(1) 采用 CMT 可视化物理根-土壤结构相互作用，(2) 使用计算机模型利用微机械方法模拟根引起的根际结构变化，以及 (3) 基于 CMT 成像和反演模型估计根际水力特性的变化，例如保水性和导水率。这项研究旨在为根际物理特性对水和土壤的作用提供变革性的见解。活植物对养分的吸收。 它可以作为更好地了解植物在土壤-大气界面关键区域中的作用的垫脚石。 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、土地复垦以及土壤-植物相互作用原理提供了新的见解。博士生和博士后将通过该项目接受培训。

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.