History Alfalfa is believed to have originated in south-central Asia and was first cultivated in
Central Asia. According to
Pliny (died 79 AD), it was introduced to Greece in about 490 BC when the
Persians invaded Greek territory. Alfalfa cultivation is discussed in the fourth-century AD book
Opus Agriculturae by
Palladius, stating:One sow-down lasts ten years. The crop may be cut four or six times a year ... A
jugerum of it is abundantly sufficient for three horses all the year ... It may be given to cattle, but new provender is at first to be administered very sparingly, because it bloats up the cattle. The medieval Arabic agricultural writer
Ibn al-'Awwam, who lived in
Spain in the later 12th century, discussed how to cultivate alfalfa, which he called (''
). A 13th-century general-purpose Arabic dictionary, Lisān al-'Arab'', says that alfalfa is cultivated as an animal feed and consumed in both fresh and dried forms. In the 16th century, Spanish colonists introduced alfalfa to the Americas as fodder for their horses. In the
North American colonies of the eastern US in the 18th century, it was called "alfalfa", and many trials at growing it were made, but generally without sufficiently successful results. Alfalfa usually has the highest feeding value of all common hay crops. It is used less frequently as
pasture. 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. Alfalfa hay is a widely used protein and fiber source for meat rabbits. In poultry diets, dehydrated alfalfa and alfalfa leaf concentrates are used for pigmenting eggs and meat because of their high content in carotenoids, which are efficient for colouring egg yolk and body lipids. Humans also eat alfalfa
sprouts in salads and sandwiches. 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. Alfalfa engages in symbiotic
nitrogen fixation with nitrogen-fixing bacteria called
rhizobia, including
Sinorhizobium meliloti. This symbiosis results in the formation of indeterminate nodules (continuously growing) which grow on the root on the root hairs. S. meliloti, once inside the nodule, will terminally differentiate into bacteroids in which they lose the ability to return to free-living growth in soil. The bacteroids fix atmospheric nitrogen into bioavailable forms such as
ammonia. Bacteroids are provided with carbohydrates for growth and return usable nitrogen to the plant. Its nitrogen-fixing ability (which increases soil nitrogen) 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. 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 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 in temperate environments, but yields have been recorded up to .
Harvesting , circa 1915. When alfalfa is to be used as
hay, it is usually cut and
baled. Loose haystacks are still used in some areas, but bales are easier for use in transportation, storage, and feed. Ideally, the first cutting should be taken at the bud stage, and the subsequent cuttings just as the field is beginning to flower, or one-tenth bloom because carbohydrates are at their highest. When using farm equipment rather than hand-harvesting, a
swather cuts the alfalfa and arranges it in
windrows. In areas where the alfalfa does not immediately dry out on its own, a machine known as a mower-conditioner is used to cut the hay. After the alfalfa has dried, a
tractor pulling a
baler collects the hay into bales. Several types of bales are commonly used for alfalfa. For small animals and individual horses, the alfalfa is baled into small, two-string bales, commonly named by the strands of string used to wrap it. Other bale sizes are three-string, and so on up to half-ton (six-string) "square" bales – actually rectangular, and typically about . Small square bales weigh from depending on moisture, and can be easily hand separated into "flakes". Cattle
ranches use large round bales, typically in diameter and weighing from . These bales can be placed in stable stacks or in large feeders for herds of horses or unrolled on the ground for large herds of cattle. or they can be handled with a grapple (claw) on the
tractor's
front-end loader. When used as feed for dairy cattle, alfalfa is often made into
haylage by a process known as
ensiling. The anaerobic fermentation of alfalfa allows it to retain high nutrient levels similar to those of fresh forage and is more palatable to dairy cattle than dry hay. In many cases, alfalfa silage is inoculated with different strains of microorganisms to improve the fermentation quality and aerobic stability of the silage.
Production During the early 2000s, alfalfa was the most cultivated forage legume in the world. Worldwide production was around 436 million tons in 2006. The US was the largest alfalfa producer in the world by area in 2009, with , but considerable production area is found in
Argentina (),
Canada (),
Russia (),
Italy (), and
China (). Alfalfa is predominantly grown in the northern and western US; In California, varieties
resistant to the
spotted alfalfa aphid (
Therioaphis maculata) are necessary, but even that is not always enough due to constant resistance evolution.
Australia Alfalfa grown in Australia prior to the 1970s was from seed brought from Great Britain in the early years of colonization, with production most successful in the
Hunter River and
Peel River valleys. Hunter River cv. was the first alfalfa variety developed for the Australian environment and was bred from selections of pre-existing alfalfa stands in the Upper Hunter River region. Pest burdens from the
spotted alfalfa aphid in the 1970s caused significant destruction of
New South Wales alfalfa paddocks, with surviving populations being used as parents for Hunterfield cv. (released 1983). This variety showed significant improvement of resistance to spotted alfalfa aphid. New South Wales produces 40% of Australia's alfalfa. all varieties grown there must be resistant to it.
South Australia is home to 83% of all alfalfa seed production in Australia. Much of this seed industry is centred around the town of
Keith, South Australia, also encompassing the neighbouring localities of
Tintinara,
Bordertown,
Willalooka,
Padthaway and
Naracoorte.
Alfalfa and bees Alfalfa seed production requires the presence of
pollinators when the fields of alfalfa are in bloom. Because older, experienced bees do not pollinate alfalfa well, most pollination is accomplished by young bees that have not yet learned the trick of robbing the flower without tripping the head-knocking keel. When western honey bees are used to pollinate alfalfa, the beekeeper
stocks the field at a very high rate to maximize the number of young bees. As a solitary but gregarious bee species, it does not build colonies or store honey but is a very efficient pollinator of alfalfa flowers. A smaller amount of alfalfa produced for seed is pollinated by the
alkali bee, mostly in the
northwestern US. It is cultured in special beds near the fields. These bees also have their own problems. They are not portable like honey bees, and when fields are planted in new areas, the bees take several seasons to build up. It is known that members of this species pollinate up to 65 different species of plants, and it is the primary pollinator of key dietary crops, such as
cranberries,
plums,
apples,
onions, and alfalfa.
Varieties Considerable research and development has been done with alfalfa. Older
cultivars such as 'Vernal' have been the standard for years, but many public and private varieties better adapted to particular climates are available. Private companies release many new varieties each year in the US. Most varieties go dormant in the fall, with reduced growth in response to low temperatures and shorter days. Traits for insect resistance have also been introduced from
M. glomerata and
M. prostrata, members of alfalfa's secondary
gene pool.
Genetic modification Genetically modified alfalfa includes
Roundup Ready Alfalfa (RRA), which tolerates
herbicide. In 2005, after completing a 28-page
environmental assessment the
United States Department of Agriculture (USDA) granted RRA nonregulated status under
Code of Federal Regulations Title 7 Part 340, which regulates, among other things, the introduction (importation, interstate movement, or release into the environment) of organisms and products altered or produced through genetic engineering that are plant pests or that there is reason to believe are plant pests.
Monsanto had to seek deregulation to conduct field trials of RRA, because the RRA contains a
promoter sequence derived from the plant pathogen figwort mosaic virus. The granting of deregulation was opposed by many groups, including growers of non-GM alfalfa who were concerned about
gene flow into their crops. Organic growers were concerned that the GM alfalfa could cross-pollinate with their organic alfalfa, making their crops unsalable in countries that ban the growing of GM crops. The District Court ruled that the USDA's environmental assessment did not address two issues concerning RRA's effect on the environment, and in 2007, required the USDA to complete a much more extensive
environmental impact statement (EIS). Until the EIS was completed, they banned further planting of RRA but allowed land already planted to continue. The USDA proposed a partial deregulation of RRA but this was also rejected by the District Court. On 21 June 2010, in
Monsanto Co. v. Geertson Seed Farms, the Supreme Court overturned the District Court decision to ban planting RRA nationwide as there was no evidence of irreparable injury. They ruled that the USDA could partially deregulate RRA before an EIS was completed. The Supreme Court did not consider the District Court's ruling disallowing RRA's deregulation and consequently RRA was still a regulated crop waiting for USDA's completion of an EIS. In July 2010, 75 members of Congress from both political parties sent a letter to Agriculture Secretary
Tom Vilsack asking him to immediately allow limited planting of genetically engineered alfalfa. However the USDA did not issue interim deregulatory measures, instead focusing on completing the EIS. Their 2,300-page EIS, published in December 2010, concluded that RRA would not affect the environment. Three of the biggest natural food brands in the US lobbied for a partial deregulation of RRA, but in January 2011, despite protests from organic groups, Secretary Vilsack announced that the USDA had approved the unrestricted planting of genetically modified alfalfa and planting resumed. Secretary Vilsack commented, "After conducting a thorough and transparent examination of alfalfa ... APHIS
[Animal and Plant Health Inspection Service] has determined that [RRA] is as safe as traditionally bred alfalfa." About of alfalfa were grown in the US, the fourth-biggest crop by acreage, of which about 1% were organic. Some biotechnology officials forecast that half of the US alfalfa acreage could eventually be planted with GM alfalfa. the
American Farm Bureau Federation, and the Council for Biotech Information warmly applauded this decision. Christine Bushway, CEO of the
Organic Trade Association, said, "A lot of people are shell-shocked. While we feel Secretary Vilsack worked on this issue, which is progress, this decision puts our organic farmers at risk." The Organic Trade Association issued a press release in 2011 saying that the USDA recognized the impact that cross-contamination could have on organic alfalfa and urged them to place restrictions to minimize any such contamination. However, organic farming groups, organic food outlets, and activists responded by publishing an
open letter saying that planting the "alfalfa without any restrictions flies in the face of the interests of conventional and organic farmers, preservation of the environment, and consumer choice". In addition to
House Agriculture Committee Chairman
Frank Lucas, Senator
Debbie Stabenow (Chairwoman of the
Senate Agriculture Committee) and Senator
Richard Lugar strongly supported the decision, respectively stating that it would give growers "the green light to begin planting an abundant, affordable and safe crop" and give farmers and consumers the "choice ... in planting or purchasing food grown with GM technology, conventionally, or organically". In a joint statement, US Senator
Patrick Leahy and Representative
Peter DeFazio said the USDA had the "opportunity to address the concerns of all farmers", but instead "surrender[ed] to business as usual for the biotech industry". In March 2011, the non-profit Center for Food Safety appealed the deregulation decision, which the District Court for Northern California rejected in 2012. == Safety concerns ==