Mouldboard plough Mould Board Plough is the most important plough for primary tillage in canal irrigated or heavy rain areas where too much weeds grow. The objective for ploughing with a Mould Board is to completely invert and pulverize the soil, up-root all weeds, trash and crop residues and bury them under the soil. The shape of mould Board is designed to cut down the soil and invert it to right side, completely burying the undesired growth which is subsequently turned into manure after decomposition.