Quantitatively analyzed root system architecture influence on root-soil mechanical interactions using 3D printing models

Background and aims

The complexity and variability of root system architectures pose significant challenges for quantitatively analyzing root-soil mechanical interactions. This study aims to understand the influence of root system architecture on root-soil mechanical interactions.

Methods

This study utilized 3D printing technology to fabricate models of various root system architectures (H-type, V-type, R-type, VH-type, and M-type), and performed a validation of the root system models. Pullout and large-scale direct shear tests were performed to assess the influence of these architectures on both root system pullout resistance and the shear strength of root-soil composites.

Results

The H-type system, characterized by the largest horizontal projection area, achieved the highest peak pullout resistance (81.3 ± 6.2 N). This extensive horizontal projection enabled the root system to support a substantial portion of the overlying soil, thereby increasing pullout resistance. The V-type and R-type systems, which exhibited the highest root area ratio at the shear plane, formed denser root networks that enhanced resistance to deformation during soil shear failure. They were the most effective in enhancing soil shear strength, with increases of 29.5 ± 2.5 kPa and 24.4 ± 1.1 kPa, respectively.

Conclusions

This work quantified the relationship between root system architecture and pullout performance, as well as the increment in shear strength, providing new insights into the mechanical interactions between roots and soil.