, a nurse crop
is an annual crop
used to assist in establishment of a perennial
The widest use of nurse crops is in the establishment of legumaceous plants such as alfalfa, clover, and trefoil. Occasionally nurse crops are used for establishment of perennial grasses.
Nurse crops reduce the incidence of weeds, prevent erosion, and prevent excessive sunlight from reaching tender seedlings. Often the nurse crop can be harvested for grain, straw, hay, or pasture.
Oats are the most common nurse crop, though other annual grains are also used.