A plough is a device for breaking up the soil in a field or garden before crops are planted. Ploughing the soil makes it softer and easier for plants to grow, and turns the soil over so any vegetation leftover from an earlier crop will go underground and add nutrients to the soil. Ploughs used to make one furrow at a time and were pulled by horses like in the picture. Today they can make dozens of furrows at a time and are pulled by tractors. An alternative spelling of plow is plough.