A discrete element method model and experimental verification for wheat root systems

Abstract

To build a general model for wheat root systems, this study tests and analyses the geometric morphology of wheat root systems in soil. On this basis, a geometric model of the wheat root system is constructed, and a discrete element model of the wheat root system is established using the bonding model. Additionally, through the analysis of the shape of the soil particles used, it is determined that the soil particles can be simplified to spheroidal and prismatic shapes, based on which a discrete element model of the soil particles is established using the Edinburgh Elasto-Plastic Adhesion model. Meanwhile, the parameters of the soil model at two water contents (11% and 14%) are obtained by the soil angle of repose test and simulation. On the basis of the above work, the accuracy of soil model parameters is verified by soil direct shear test, and the accuracy of the root system bonding model and parameters, as well as the root-to-soil contact model and parameters, are verified by pulling tests and simulations of actual single roots in soil. At the same time, the feasibility and effectiveness of the general model of the wheat root system established are proven through the comparison between the pulling test and simulation of the actual root system in soil, which provides a reference for the study of the overall modelling of the wheat plant and the simulation of the contact interaction between the root system and agricultural machinery components during postharvest tillage.