Medicago sativa L., alfalfa, is a long-lived perennial legume. Flowers vary in color from purple to yellow and are borne in loose clusters. Pods of alfalfa range from the sickle type to those that are twisted into spirals.
Each pod contains several small kidneyshaped seeds. Alfalfa’s stems are erect and grow from a woody crown to about 2 to 3 feet tall. New growth occurs from buds in the crown. The plant has a tap root which may penetrate deep into the soil. Leaves are alternately arranged on the stem and are normally trifoliate.
Adaptation and Distribution
Alfalfa grows best on deep, well-drained, friable soils. Lands subject to frequent overflows or high water tables are unfavorable for alfalfa. The pH of the soil should be 6.5 or above. Alfalfa is distributed throughout the entire United States.
A seedbed must be smooth, firm, free of weeds and trash, and contain adequate moisture for germination and emergence. Land grading must be sufficient to ensure good surface draining. Alfalfa should not be seeded as a first crop on newly leveled land where fill may settle and cause poor surface drainage.
Five pounds of scarified, properly inoculated pure live seed (PLS) per acre evenly drilled ¼-inch deep on adapted, properly prepared sites will produce adequate stands. A combination drill and packer is desirable.
Cultipacking soil before and after seeding is helpful to establishing a stand. Seeding depths should be no greater than ¼ inch on finer textured soils and no greater than ½ inch on sandy soils Spring seedlings can be made 30 days before the average date of last killing frost. Other dates of seeding may be made during the late summer.
In general, graze or cut for hay when alfalfa is in early bloom. Graze or cut to about a 2-inch height. Successive grazings and cuttings for hay should occur at ¼ bloom stage or after a 5 to 6 week recovery period. Alfalfa can best withstand grazing if rotated frequently or grazed in small strips. The last cutting of alfalfa should be made 3 to 4 weeks before the first killing frost date.
Alfalfa may cause livestock to bloat. Care should be used in managing such grazing to reduce the possibility of this hazard.
Pests and Potential Problems
Alfalfa is susceptible to the spotted or pea aphid, alfalfa weevil, stem nematode, bacterial wilt, snout beetle, and several leaf spots.
Crops: Alfalfa is harvested as hay which is processed or fed directly to livestock, or for seed production. It is also used in pellets as forage supplements.
Livestock: This plant is grown in combination with grasses in improved pastures. It is grazed by all types of domestic livestock. Caution should be taken when using alfalfa for grazing due to its high bloat hazard.
Wildlife: Alfalfa is an excellent food for antelope, deer, elk, Canada goose, and sage and sharp tail grouse. It is fair food for sandhill crane, mallard, Hungarian partridge, and pheasant.
In addition to providing high quality hay, grazing, and wildlife forage and protection, alfalfa is an important source of leaf meal used for fortifying baby food and other special diet foods prepared for human use. Large quantities of dehydrated alfalfa are also used in manufacturing concentrated feeds for poultry and livestock.
This plant may become weedy or invasive in some regions or habitats and may displace desirable vegetation if not properly managed.