This study aimed to enhance the understanding of root–soil interaction at a microscale level and its implications for practical land management, ecosystem restoration, and engineered solutions on vegetated slopes. Specifically, the interaction between tall fescue roots and sand was investigated using four-dimensional (4D) CT scanning. The growth process of tall fescue roots in sand was tracked on the 2nd, 4th, 6th, and 8th days after seed transplantation. To accurately segment root–soil CT images and overcome challenges such as the partial volume effect (PVE) and the similarity of root water grayscale in CT images, a semiautomatic segmentation process was employed. The analysis focused on examining the evolution of three-dimensional root parameters throughout the growth process. The findings highlighted the significant influence of initial porosity on tall fescue root development, the global decrease in saturation with root growth, and the predominant impact of pore distribution on local saturation distribution. The study revealed that the root system's influence on saturation, on the eighth day after transplantation, extended up to 800 pixels (8 mm) from the root surface. These results have practical implications for optimizing planting density and providing effective planting strategies for vegetated slope design in engineering applications.

本研究旨在增强对微观层面上根系与土壤相互作用的理解及其对实际土地管理、生态系统恢复和植被斜坡工程解决方案的影响。具体来说，使用四维 (4D) CT 扫描研究了高羊茅根和沙子之间的相互作用。种子移植后第2、4、6、8天追踪高羊茅根在沙中的生长过程。为了准确分割根部-土壤CT图像并克服CT图像中部分体积效应（PVE）和根部水灰度相似性等挑战，采用了半自动分割过程。该分析的重点是检查整个生长过程中三维根参数的演变。研究结果强调了初始孔隙度对高羊茅根系发育的显着影响、根系生长导致的整体饱和度下降以及孔隙分布对局部饱和度分布的主要影响。研究表明，移植后第八天，根系对饱和度的影响从根部表面延伸至 800 像素（8 毫米）。这些结果对于优化种植密度和为工程应用中的植被边坡设计提供有效的种植策略具有实际意义。