Evaluation of rotary mixing effects on soil structure and tillage resistance using discrete element method
Abstract
Simulation of tillage operations is critical for precision management of soil-tool interactions, facilitating the conservation of soil structure. Improper use of machinery during land preparation in agriculture may lead to soil structure destruction. This paper aimed to analyze the effect of deep tillage on soil structure and the measured and simulated tillage resistance of the subsoiler cum rotary mixing implement. Soil bin measurements were collected using a motorized trolley with resistance sensors and a soil profilometer. A 3D geometry of the implement was created using PTC Creo Parametric 3D Modelling software, and the soil bed was modeled by discrete element (DE) particles using EDEM software. Accurate calibration of the DE model parameters was achieved by reproducing the soil bin. The cohesion between the particles was created by adding a cohesion resistance to the normal contact resistances to simulate the actual cohesive soil. It was found that the shape of the rotary blades significantly impacts the measured tillage resistance, the formed soil profile, and the simulations. The relative error of 0.4%, 4.9% and 4.2% was obtained for horizontal resistance, vertical resistance and soil profile respectively. The horizontal resistance showed the best regression results of 0.9997 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\:{R}^{2}$$\end{document} at a \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\:NRMSE$$\end{document} of 0.04, followed by the soil furrow with 0.9936 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\:{R}^{2}$$\end{document} and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\:NRMSE$$\end{document} of 0.23 and vertical resistance with 0.9 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\:{R}^{2}$$\end{document} and a \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\:NRMSE$$\end{document} of 0.27. The unpaired T-Test showed no statistically significant difference \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\:(p>0.05)$$\end{document} between simulation and experimental results. Regardless of tillage depth, soil layers cannot be destroyed with the proper blades on rotary tillers. DEM can be used as an accurate, consistent, and fast method of effectively predicting the final soil condition and resistances needed for tillage operations. This paper presents DEM to analyze the effect of deep tillage on soil structure. The resistance sensors in the motorized trolley were used to measure soil tillage resistance during deep tillage operations. The DEM is useful in the optimization of tillage tools. The developed model was NS for the unpaired t-test \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\:(p>0.05)$$\end{document}. This paper presents DEM to analyze the effect of deep tillage on soil structure. The resistance sensors in the motorized trolley were used to measure soil tillage resistance during deep tillage operations. The DEM is useful in the optimization of tillage tools. The developed model was NS for the unpaired t-test \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\:(p>0.05)$$\end{document}.
