Modeling of soil-tool interaction in material incorporation

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Incorporation of organic materials into soil has significant benefits to the environment, soil fertility, and soil erosion protection. The goal of this research is to develop a unique and universal approach to design soil engaging tools (sweeps, discs, openers, rolling tines, etc.) for efficient incorporation of organic materials (such as livestock manure and crop residue) into soil in agriculture. Problems associated with the existing soil engaging tools include logging of crop residue in conservation tillage systems, high soil disturbance in forage and no-till systems, and high requirement of energy for operations. At a time when world food demand, cost of energy, and environmental impact are a matter of fact, it becomes urgent to rejuvenate soil engaging tools design to improve their efficiency and effectiveness. The performance of a soil engaging tool highly depends on how it interacts with soil and the organic materials they deal with. Currently, the design of commercial soil engaging tools still rely on the traditional soil-tool interaction models on soil behaviour and soil-tool interactions. In most traditional models, the Finite Element Method (FEM) was used and soil is considered as a continuous elastic-plastic media, whereas, soil behaves as a discontinuous media and flows as individual particles (aggregates and clods) around the tool. Thus the FEM is not fully capable to model agricultural soil and soil-tool interactions at the particle levels. Also, the FEM is not able to deal with a mixture of different materials at the "particles" levels, such as mixing crop residue "particles" with soil "particles". These incapacities of FEM have limited soil engaging tool design for ages. The Discrete Element Method (DEM) allows to model soil as an assembly of aggregates/clods and deal with more than one types of particles encountered in material incorporations. Using the DEM in soil dynamics is an emerging field, and this field is at its infancy stage. The proposed research will take a significant step in advancing the field, with the available expertise and research tools in the applicant' lab, the last soil dynamics lab in Canada which is fully functional.