Simulated and Experimental Analyses of a Toothed Rolling Coulter for Cutting Crop Residues

Rolling cutting coulters are extensively used to cut plant residues, left on the soil surface, so as to facilitate the work of tillage tools in reduced tillage or direct drilling practices. Four basic patterns of these coulters are available in the market: smooth, notched, ripple, and wave. These coulters have operational problems and usually do not cut the residue efficiently. When the soil is dry, they demand high vertical load to penetrate and, when the soil is wet, they push the residue into the soil without cutting it. This work presents a new geometry for cutting coulters, making them capable of cutting through residue under any soil condition, eliminating build-up and reducing implement draught. The work was developed in two stages: a computational routine to calculate the dimensions of the coulter and to simulate its behaviour; and laboratory tests carried out with three-teeth coulters with different diameters. The results showed that the toothed coulter performed adequately in cutting the residues. The vertical load necessary for soil penetration at 70 mm working depth demanded by the toothed disc coulter varied between 1·5 to 2·1 kN. The moment demanded by the toothed coulter varied from 55·2 up to 86·5 Nm.