Alfalfa (Medicago sativa)

Medicago sativa, commonly called alfalfa in North America and lucerne in the United Kingdom, South Africa, Australia and New Zealand, is a perennial flowering legume of the family Fabaceae grown to about one meter tall, with trifoliolate leaves and clusters of small flowers usually purple but sometimes blue, yellow or cream. Its root system is unusually deep, typically reaching two to three meters and occasionally more than fifteen meters in search of groundwater, and the plant fixes nitrogen through a symbiosis with rhizobia bacteria that enriches the soil it grows in. It originated in south-central Asia, where it was first cultivated, reached Greece around 490 BC amid the Persian invasions, and was carried to the Americas by Spanish colonists in the sixteenth century, with California becoming a major growing region after seeds arrived from Chile in the 1850s. As a forage crop used for grazing, hay and silage, it has served as livestock fodder since antiquity and today ranks among the world most important legume crops, supplying high protein feed for dairy and beef cattle.