ALFALFA: CHARACTERISTICS, HABITAT, REPRODUCTION, PROPERTIES - BIOLOGY - 2025

The alfalfa (Medicago sativa) is a leguminous perennial erect growth belonging to the family Fabaceae. Native to Asia Minor and the South Caucasus, today it is one of the main forage crops in temperate countries.

Little branched perennial plant that reaches 100 cm in height, trifoliate leaves with obovate leaflets, slightly serrated apex and stipules serrated at the base. Zygomorphic flowers of violet, purple and yellow, the fruit is a legume with yellow kidney-shaped seeds.

Alfalfa (Medicago sativa). Source: AnRo0002

Like most legumes, its roots maintain a symbiotic relationship with certain microorganisms in the soil, such as the Sinorhizobium meliloti bacteria. This association favors the fixation of atmospheric nitrogen, increasing the nitrogen in the soil and its availability in the crop that is used as forage.

The various varieties of alfalfa grown commercially constitute one of the legumes of greatest importance as forage for livestock feed. By containing a high level of proteins and minerals, they favor its palatability and digestibility for a large number of animal species.

On the other hand, the diversity and quality of its nutrients makes it a nutritional supplement for human consumption. Its regular intake helps alleviate disorders related to malnutrition, asthenia, anemia, weakness and other nutritional ailments.

Evolutionary origin

The Medicago sativa species is native to Asia Minor and the South Caucasus, in present-day Iraq, Iran, Syria, Turkey, Afghanistan and Pakistan. Since the Bronze Age there has been a reference to a plant of high nutritional value that was consumed by horses from Central Asia.

During the Medical Wars, in the middle of 490 a. C., it was introduced in Greece through the food provided to the cavalry from Persia. The seed from this forage served to establish the first crops in the Mediterranean basin, mainly destined for animal consumption.

Later it went to the Iberian Peninsula from where it was distributed throughout Europe, and from there to America in the middle of the 16th century. At present, it is a cosmopolitan crop, in addition its sprouts are a highly appreciated food for human consumption for its nutritional and therapeutic properties.

Alfalfa flowers (Medicago sativa). Source: javier martin

General characteristics

Appearance

Herbaceous plant of evergreen condition and erect or slightly decumbent position, branched, usually lives 4 to 12 years. The adult plant can reach a variable height of 40-100 cm and are characterized by the variable hairiness of their surface.

Root

Main root of the pivoting or fusiform type of vertical and deep growth, covered by numerous secondary roots that sprout laterally. In alfalfa, the root is vigorous, long and deep, which allows it to absorb the nutritive elements located more than 5 m deep.

Stem

Herbaceous and erect stem with ascending growth, usually covered with whitish hairs, at the base there is a sublenose and perennial crown. This crown, approximately 20 cm in diameter, has numerous shoot buds or shoots that are located below ground level.

Leaves

The pinnate and trifoliate leaves have obovate, oblong or oblanceolate leaflets, 5-20 mm long by 3-10 mm wide. Whole green leaflets, finely serrated at the apex, appressed pubescence, long and ribbed petiole, with triangular stipules welded to the base.

flowers

Zygomorphic flowers with differentiated calyx and corolla, 6-12 mm diameter violet and yellow corolla, green campanulate pentameric calyx. The flowers are arranged in inflorescences or peduncular racemes in axillary position, with the peduncle longer than the petioles of the adjacent leaves.

Fruit

The fruit is a legume or falcada or spiral pod, curled on itself, delayed indehiscent, brown to blackish when ripe. In its interior the seeds are located in variable numbers (2-6), reniform, 2-3 mm long and with a yellowish seed coat.

Alfalfa fruit (Medicago sativa). Source: Philmarin

Taxonomy

- Kingdom: Plantae

- Division: Magnoliophyta

- Class: Magnoliopsida

- Subclass: Rosidae

- Order: Fabales

- Family: Fabaceae

- Subfamily: Faboideae

- Tribe: Trifolieae

- Gender: Medicago

- Species: Medicago sativa L., 1753

Subspecies

- Medicago sativa subsp. ambigua (Trautv.) Tutin

- Medicago sativa subsp. Urban microcarpa

- M. sativa subsp. sativa L.

- M. sativa subsp. varia (J. Martyn) Arcang.

Etymology

- Medicago: the generic name is a Latin word that comes from the Greek terms «μηδική» pronounced «medicé» and «πόα» pronounced «póa». "Mediké" means "medical" in reference to the Medes, ancient Persian people, and "póa" means "grass", which is translated as "Persian grass". These expressions were Latinized as "medicago."

- sativa: the specific adjective derives from the Latin «sativus, -a, -um» which translates to «sativa», that is to say, what is sown, planted or cultivated.

Details of alfalfa flowers. Source: Stefan.lefnaer

Habitat and distribution

The Medicago sativa species is widely cultivated around the world, found in the wild along roadsides or roadsides. Likewise, it has naturalized in savannas and grasslands on dry soils in cold or temperate climates.

It is grown commercially in a wide variety of soils and climates at elevational levels between 700 and 2,800 meters above sea level. It grows on loamy, deep and well-drained soils of moderate salinity or alkaline, since a pH lower than 5.00 drastically limits its development.

It develops in environments with an average temperature between 15-25 ºC during the day, and night temperatures of 10-20 ºC. It is resistant to drought, thanks to its extensive root system that draws water from the deeper layers.

However, it is susceptible to waterlogging that causes root rot and alters the symbiosis with the specific Sinorhizobium meliloti. In fact, its symbiotic activity is also restricted with the soil pH, values ​​lower than 5-6 require the application of agricultural amendments.

Cultivated worldwide, the subspecies Medicago sativa subsp. Is common in the Mediterranean basin. sativa and northern Eurasia Medicago sativa subsp. falcata. In the Iberian Peninsula its cultivation is carried out in large areas of the Ebro valley to the northeast and the Duero valley to the northwest.

Alfalfa leaves. Source: Photo by David J. Stang

Reproduction

Sowing

The commercial reproduction of alfalfa is carried out by means of seeds, it is a fast germination and implantation crop. In case of irrigation, it is established as a monophyte crop, in dry conditions it is customary to associate with another grass such as oats, barley or cut grasses.

For one hectare of sowing, 20-25 kg of seed are required. During the establishment it is required that the land is tilled and mowed, in order to avoid the appearance of weeds during the growth phase.

Sowing is usually established during the fall, while in regions with strong winters, sowing can be done during the spring. The productive life of this species varies from 6-8 years, depending on environmental conditions, variety of the species, crop health and agronomic management.

Driving

Sowing takes place between March and May, so that the plant develops at least three trifoliate leaves before the first frosts. The cool temperature and humidity of the soil during the autumn, favors the nodulation of the nascent root system, guaranteeing the supply of nitrogen during the spring.

A tilled soil is required to provide a stable seedbed with good moisture availability. Sowing is done by broadcast, but if the conditions of the terrain allow it, planting lines can be drawn to facilitate agronomic management. In the case of associated cultivation, it is recommended to alternate one line of grass with two lines of alfalfa.

Soil conditions are essential for the proper development of alfalfa, as it is tolerant to drought, but susceptible to waterlogging. The waterlogging of the soil tends to reduce the availability of oxygen in the roots, which causes a rapid deterioration and subsequent death of the plant.

The vigorous and extensive root system requires deep and well-drained soils, the surface water tables hinder its effective development. Although it grows on sandy loam soils, it thrives well on fine and humid soils, although with less intensity.

Sinorhizobium meliloti on alfalfa roots. Source: Ninjatacoshell

Nutrition

Alfalfa is a forage plant that supplies excellent levels of quality proteins, minerals and vitamins. Its high energy value is related to the nitrogen value as a food supplement or forage.

Of the great variety of components present, the alkaloids betaine and stachidrine, non-soluble fibers and pectin, proteins, saponins and tannins stand out. The amino acids arginine, asparagine, and tryptophan, as well as the minerals aluminum, boron, calcium, chromium, cobalt, phosphorus, iron, magnesium, manganese, potassium, selenium, silicon, sodium, and zinc.

Similarly, caffeic, citric, fumaric, malic, medicagenic, synaptic, succinic and oxalic acids, and the phytosterols β-sitosterol, campesterol and stigmasterol. Apart from pigments such as chlorophyll and xanthophyll, folates, inositol, niacin, riboflavin, thiamine, vitamin A, C, E, K and D in traces, which influence animal nutrition.

Alfalfa plant illustration. Source: Amédée Masclef

Nutritional value per 100 g

- Energy: 20-25 kcal

- Carbohydrates: 2.0-2.5 g

- Dietary fiber: 1.8-2.0 g

- Fats: 0.5-0.8 g

- Proteins: 4 g

- Thiamine (vitamin B ₁): 0.076 mg

- Riboflavin (vitamin B ₂): 0.126 mg

- Niacin (vitamin B ₃): 0.481 mg

- Pantothenic acid (vitamin B ₅): 0.563 mg

- Pyridoxine (vitamin B ₆): 0.034 mg

- Vitamin C: 8.2 mg

- Vitamin K: 30.5 μg

- Calcium: 32 mg

- Phosphorus: 70 mg

- Iron: 0.96 mg

- Magnesium: 27 mg

- Manganese: 0.188 mg

- Potassium: 79 mg

- Sodium: 6 mg

- Zinc: 0.92 mg

Properties

Alfalfa is cultivated as fodder, which is why it is considered a food supplement of high nutritional value for cattle and horses. Its consumption in human food is occasional, however, it is a product rich in minerals, vitamins, proteins and fibers that provide great benefits for health.

Photochemical analysis has made it possible to determine the presence of essential vitamins of group A, D, E and K, including the entire family of group B. In fact, each vitamin provides a particular benefit, hence its importance for health in general.

Vitamin A favors the formation of epithelial cells, the protection of the skin and the strength of the bone system. For its part, vitamin D regulates calcium in the bones, protecting against rickets. Vitamin E has antioxidant principles, being an essential element for the production of hemoglobin.

Alfalfa seed sprouts. Source: pixabay.com

Medicinal

In herbology, the leaves, seeds and shoots of this species are used for their medicinal and therapeutic properties. Indeed, alfalfa is commonly used for its alkalizing, antiarthritic, antibacterial, anticolestaemic, antispasmodic, antidiabetic, anthemorrhagic, antipyretic, antirheumatic, aperitive and antiviral qualities.

Its consumption is indicated for the treatment of kidney diseases, bladder infections, inflammation of the prostate or to increase diuresis. In the same way, it is consumed to regulate cholesterol and diabetes levels, control asthma, stomach discomfort and rheumatic discomfort such as arthritis and osteoarthritis.

Sprouts are typically eaten fresh as a source of vitamins A, C, E, and K, as well as the mineral elements calcium, phosphorus, iron, and potassium. In addition, it is attributed anti-anemic, anti-inflammatory, diuretic, digestive, galactogenic, emmenagogue, hemostatic, lipid-lowering, vitamin, restorative and remineralizing properties.

This plant acts as a powerful diuretic, which together with its anti-inflammatory effect makes it an effective remedy for treating urinary disorders. In this case it is recommended to relieve cystitis or bladder disorders, nephritis or inflammation of the kidney, prostatitis or inflammation of the prostate duct and prevent the presence of kidney stones.

Similarly, it acts as a powerful cleanser and detoxifier. Indeed, its high content of coumarin has shown its effect in restructuring the skin, being ideal for preventing acne, eczema, dermatitis and psoriasis.

Forage

As an animal feed supplement, it is a legume that is distinguished by its high nutritional value and high productive capacity. Its high nitrogen content, due to the ability of symbiosis with the Rhizobium in the soil, results in a species highly desired by livestock.

The cultivation of alfalfa allows to increase the animal load, improve the weight gain of the animal and the milk production performance. In addition, it constitutes a safe source of high quality forage, harvested and stored as a forage reserve, maintaining its nutritional quality.

References

1. Alfalfa (2019) Web Consultas Healthcare, SA Recovered at: webconsultas.com
2. Clavijo Villamizar, E., & Cadena Castro, PC (2011). Production and nutritional quality of alfalfa (medicago sativa) planted in two different environments and harvested at different phenological stages. (Degree Thesis) University of La Salle. Faculty of agricultural sciences. Animal husbandry program. 35 pp.
3. Maddaloni, J. & Ferrari, L. (2005) Forage and Pastures of the Temperate Humid Ecosystem of Argentina, 2nd Edition. INTA. 542 pp. ISSN: 987-9455-49-5.
4. Martínez, R., Nebot, E., Porres, JM, Kapravelou, G., Moral, AD, Talbi, C.,… & López-Jurado, M. (2015). Medicago sativa L: improvement and new aspects of its nutritional and functional value by bacterial co-inoculation. Hospital Nutrition, 32 (6), 2741-2748.
5. Medicago sativa. (2019). Wikipedia, The Free Encyclopedia. Recovered at: es.wikipedia.org
6. Odorizzi, AS (2015). Genetic parameters, yield and forage quality in alfalfa (Medicago sativa L.) extremely without rest with variable expression of the multifoliolate character obtained by recurrent phenotypic selection. (Graduate Thesis) National University of Córdoba. Faculty of agricultural sciences. 167 pp.
7. Piñeiro Andión, J. (2011). Alfalfa and its mixtures with grazing grasses. Pastures, 16 (1-2), 133-141.
8. Rojas-García, AR, Torres-Salado, N., Cancino, SN, Hernández-Garay, A., Maldonado-Peralta, MDL Á., & Sánchez-Santillán, P. (2017). Yield components in alfalfa varieties (Medicago sativa L.). Agrociencia, 51 (7), 697-708.