Nonlinear Dynamic Process of Soil Tillage Under Straw Mulching Model

Abstract

Soil tillage is the important research topic in the field of soil and agricultural engineering. By discrete element method (DEM), it simulated the resistance change of bulldozing plate under the influence of particle in the grass, and it found that the peak resistance of the weeds on bulldozing plate was 3.5 times the mean resistance. It set up the straw tillage experimental platform and straw discrete element models of three different sizes which were 7, 13, 19 mm. By the contrast tests of simulating the soil tillage process with straws, it researched the nonlinear motion of the straw and soil particles and the coupling process with disc plough. It found that, because the tillage process changed original soil surface morphology, the soil void ratio increased after the tillage, and obvious shallow gullies appeared after the plough. As continuously promoting the process of tillage, some particles were cut to separate twice. The higher the haulage speed was, the more soil particles which were uplifted by disc plough onto the leading edge of plough were, the greater resistance which provided by soil onto the leading edge of plough was, the grater the traction work was. The displacement of 7 and 19 mm straws to the both sides were obvious, while the displacement of 13 mm straw along the leading edge of plough is obvious. 13 mm straw contacted the plough surface again, which leaded to a significant change in speed, and the simulation results matched well with the theoretical results.