disk plow or disk, farm implement employing a row or rows of concave circular steel disks that cut and pitch the soil in a way somewhat similar to a moldboard plow. It can be used in many situations where the latter will not work, such as dry crusty soil, rough ground, or sticky gumbo. The one-way disk has essentially replaced other plows in areas where wind erosion of the soil is a problem as it can work the soil without turning it completely over, thus leaving the stubble on top for protection. This type of disk can also be fitted with attachments for seeding small grains.
See H. P. Smith and L. H. Wilkes, Farm Machinery and Equipment (6th ed. 1976); C. Culpin, Farm Machinery (11th ed. 1986).