Evaluation of disc coulters for a zero till system
Vaishnav, Ashok S.
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The basic problem associated with no-till and minimum tillage seeding operations is the presence of crop residue on fields which does not get cut with the existing seeding machines. This failure to cut crop residue results in improper placement of seed. Special seeding machines have been designed, (e.g., Haybuster 1206 grain and fertilizer drill) to overcome these problems. These machines require extra investment for farmers already having conventional seeding machines if they want to practice minimum and no-tilling farming. The study was, therefore, undertaken to determine the performance of disc coulters under zero-till practice in the soil bin under different soil conditions and to provide design criteria for modification of existing seed drills so that they could be used under no till conditions. Cone index data on soil penetration resistance and soil moisture content were obtained from no-tilled and fall tilled fields at seeding time to simulate field conditions in the soil bin. Three sizes of disc coulters were evaluated for their cutting ability of the crop-residue in the soil bin. The data of cone index of packed soil, its moisture content, straw moisture content and straw density were also measured. Draft and vertical forces on coulters were reported for each test. Observations and analysis of data indicated a varying degree of crop residue being cut by the coulters under different soil conditions. The disc coulter 460 mm diameter performed satisfactorily and cut the straw at densities up to 5000 kg/ha at 50 mm depth of penetration and deeper.