Alfalfa, Medicago sativa, a legume forage plant belonging to the pea family Leguminosae, has been an animal feed longer than any other forage crop. Alfalfa was planted in hot, dry regions of Mesopoamia before recorded history. It now is grown throughout the world under extremely varied climatic conditions. The United States produces between 73,000 and 82,000 metric ton annually.Alfalfa is a perennial plant and will under normal conditions live for 5 or more years. It shoots may grow to stems of more than 1 m (3 ft). The plant produces compound leaves and yellow to purplish blue flowers, and kidney-shaped seeds develop inside the curled pods. The roots are extraordinary long, often extending more than 7 m (25 ft) deep, which makes alfalfa an ideal crop for dry climates. It also enriches soil with nitrogen.
Alfalfa will grow in a wide variety of conditions, but it does best in deep, loamy, well-drained soils. It responds well to irrigation and to fertilizers. Seed is generally sown in the spring in cooler climates or in the fail if winter temperatures are moderate. It can be sown with other grains, such as oats, to reduce growth. When sown for pasture, it is sometimes mixed with rye, bromegrass, bluegrass, timothy, or fescue.
Procedure used to harvest alfalfa depend on the yield, nutrition quality, and physical condition desired. The maximum yield occurs when the plant is cut at full bloom, but other considerations such as stem size, moisture, and vitamin content may alter cutting time. Cuttings range from two to seven or eight a year, depending on the environment.
Alfalfa is valuable for feeding all kinds of livestock. It is used for pasture, for soil building, for dehydration, as meal, or as silage. Dehydrated alfalfa is a common ingredient of feedstuffs and supplies vitamins, protein, lipids, and minerals.