A model of root elongation by dynamic contact interaction

Recent findings on the functions of roots from the chemical and biological standpoints have strengthened the need for research on the mechanisms of root growth by physical and mathematical approaches. This study was aimed at developing a root growth model, based on dynamic interactions between the root and its ambient environment. As a tool for modelling, we employed the discrete element method (DEM) with the assumption that root growth could be expressed in terms of dynamic interactions between growing root elements and soil elements. Using a corresponding time scale, the results of a DEM simulation indicated a sufficiently accurate shape of root elongation, which could be verified by a root growth experiment. Moreover, a comparison of fractal dimensions from DEM results and experimental results showed almost similar values of 1.0, which is the dimension of a line.