Other forms: tilths
Tilth is land that has been plowed, sowed, and yes, tilled, and is ready to be used for raising crops. An active farm should have plenty of tilth.
Tilth is also called tilled land. The words tilth and till come from an Old English word that means basically “to labor, to work.” Tilth is what happens when you work the soil. This unusual-looking word has had several meanings related to work and cultivation, but its main meaning is a type of land that's been used by farmers for their crops.