Harrow
After ploughing, other implements were used. The harrow was necessary to smoothen the soil in areas where the soil remained rough. It consists of a wooden or metal framework bearing metal disks, teeth, or sharp projecting points, called tines, which is dragged over plowed land to crush the clods of earth and level the soil. Harrows are also used to uproot weeds, aerate the soil, and cover seeds.
In the beginning the harrows were as simple as a tree branch but the harrow became more sophisticated after the Industrial Revolution. By the 1790s, two distinct types of harrows were in use: the square and the triangle, or "A" frame. The square harrow was used on old fields that were free of large obstructions, while the triangular frame was used on freshly ploughed fields. These models had wooden frames with wood or iron teeth.
In modern times, harrows are of varied types. Some are simply dragged behind a tractor or draft animal; some are suspended on wheels; many have levers to adjust the depth of the cut.