The disc harrow is an agricultural tool used to prepare a field for planting by breaking up dirt clods, leveling the surface of the field and packing the dirt so there are few air holes in which water can gather. The disc harrow can also be used to plant seed.
A disc harrow consists of a row of discs that are dragged along the ground across a field to cut into the soil. The discs can be adjusted for depth, and are curved to help cut smoothly and evenly as they are dragged by a tractor. Disc harrows can also be used to prepare fields for going fallow by cutting up any crop remnants or weeds and burying them in the soil to add nutrients for future planting.
The same methods used to prepare soil for future planting are also good for preparing clay fields with cover crops to make the field richer and more able to produce. The disk harrow is used to lightly chop the cover crops into the field without destroying the root system of the crop, enriching the soil in the process. The disc harrow can also be used to spread fertilizers at the same time, using the same boxed add-ons as are used to spread seed.