AppearanceIt superficially resembles clover, with clusters of small purple flowers followed by fruits spiralled in 2 to 3 turns containing 10-20 seeds. Alfalfa is native to warmer temperate climates. It has been cultivated as livestock fodder since at least the era of the ancient Greeks and Romans.
NamingThe name alfalfa is used in North America. The name lucerne is the more commonly used name in the United Kingdom, South Africa, Australia, and New Zealand.
HabitatAlfalfa is a perennial forage legume which normally lives four to eight years, but can live more than 20 years, depending on variety and climate. The plant grows to a height of up to 1 m, and has a deep root system, sometimes stretching more than 15 m. This makes it very resilient, especially to droughts. It has a tetraploid genome.
Alfalfa is a small-seeded crop, and has a slowly growing seedling, but after several months of establishment, forms a tough "crown" at the top of the root system. This crown contains many shoot buds that enables alfalfa to regrow many times after being grazed or harvested.
CulturalAlfalfa is widely grown throughout the world as forage for cattle, and is most often harvested as hay, but can also be made into silage, grazed, or fed as greenchop. Alfalfa usually has the highest feeding value of all common hay crops. It is used less frequently as pasture. When grown on soils where it is well-adapted, alfalfa is often the highest-yielding forage plant, but its primary benefit is the combination of high yield per hectare and high nutritional quality.
Its primary use is as feed for high-producing dairy cows, because of its high protein content and highly digestible fiber, and secondarily for beef cattle, horses, sheep, and goats....hieroglyph snipped... Alfalfa hay is the most widely used fibre source in rabbit diets. In poultry diets, dehydrated alfalfa and alfalfa leaf concentrates are used for pigmenting eggs and meat, due to their high content in carotenoids, which are efficient for colouring egg yolk and body lipids. Humans also eat alfalfa sprouts in salads and sandwiches....hieroglyph snipped... Dehydrated alfalfa leaf is commercially available as a dietary supplement in several forms, such as tablets, powders and tea. Fresh alfalfa can cause bloating in livestock, so care must be taken with livestock grazing on alfalfa because of this hazard.
Like other legumes, its root nodules contain bacteria, ''Sinorhizobium meliloti'', with the ability to fix nitrogen, producing a high-protein feed regardless of available nitrogen in the soil....hieroglyph snipped... Its nitrogen-fixing ability and its use as an animal feed greatly improve agricultural efficiency.
Alfalfa can be sown in spring or fall, and does best on well-drained soils with a neutral pH of 6.8 – 7.5....hieroglyph snipped... Alfalfa requires sustained levels of potassium and phosphorus to grow well. It is moderately sensitive to salt levels in both the soil and irrigation water, although it continues to be grown in the arid southwestern United States, where salinity is an emerging issue. Soils low in fertility should be fertilized with manure or a chemical fertilizer, but correction of pH is particularly important. Usually a seeding rate of 13 – 20 kg/hectare is recommended, with differences based upon region, soil type, and seeding method. A nurse crop is sometimes used, particularly for spring plantings, to reduce weed problems and soil erosion, but can lead to competition for light, water, and nutrients.
In most climates, alfalfa is cut three to four times a year, but it can be harvested up to 12 times per year in Arizona and southern California. Total yields are typically around eight tonnes per hectare in temperate environments, but yields have been recorded up to 20 t/ha . Yields vary with region, weather, and the crop's stage of maturity when cut. Later cuttings improve yield, but with reduced nutritional content.
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