Alfalfa (Medicago sativa), also called lucerne, is a perennial flowering plant in the pea family Fabaceae cultivated as an important forage crop in many countries around the world. It is used for grazing, hay, and silage, as well as a green manure and cover crop. It adds organic bulk to the soil and should be dug in whilst plants are fresh and green. If grown long term, it should be cut down 2 to 3 times a year to encourage new growth, the cuttings can be composted or left on soil surface as a mulch..