Simulation of root development based on the dielectric breakdown model

Abstract

Knowing the root distribution in soil is essential for estimating water uptake by plant roots. It is difficult, however, to characterize and model undisturbed root systems. Root development in a two-dimensional potential field is simulated with the dielectric breakdown model (DBM), which implies a similarity between electric discharge and root distribution. A weighted potential gradient with an exponent η was used to create probability distributions of root growth. Each root was generated step-by-step by selecting random numbers from probability distributions. Simulations were performed for point sources and horizontal line sources. In both cases, as η increased, the root system changed from a cluster and dense type to a slender and sparse type and the fractal dimension decreased. For a point source of water, there was a definite pattern of root development toward the source. It is concluded that the DBM effectively describes root development under various water conditions.