Alfalfa

Alfalfa, Medicago sativa, is an herbaceous perennial in the plant family Fabaceae (peas and beans) which is primarily grown as a forage crop which can be grazed by animals or harvested as hay to be used as an animal feed. Alfalfa has a deeply penetrating taproot and the stems of the plant branch from a woody base, growing upright and erect or along the ground. The leaves of the plant are made up of three individual leaflets (trifoliate) which are are narrow and oval or oblong in shape with a smooth upper surface and slightly hairy lower surface. Alfalfa plants produce flowers on racemes (flower stalks) and each raceme possesses 10–35 densely packed purple flowers. Alfalfa produces spirally coiled seed pods each containing 2–6 seeds. Pods may have a smooth or hairy outer surface. Alfalfa plants can reach a height of 120 cm (47 in) and live for between 3 and 8 years. Alfalfa is also commonly referred to as lucerne and is believed to have originated in Caucasus area, north-western Iran and north-eastern Turkey.

Crop Details

Scientific Name: Medicago sativa 

Common Name: lucerne, purple medic (En); alfalfa, mielga (Sp); luzerne (Fr); luzerna (Pt); अल्फाल्फा (Hi).

Alfalfa seed pods

Alfalfa beds in field

Alfalfa plants in bloom

Alfalfa flowers

Close-up image showing trifoliate alfalfa leaf

Healthy alfalfa foliage

Alfalfa ready for cutting

Alfalfa leaves are edible and can be eaten as a leafy vegetable. Alfalfa is used primarily as forage for animals and is cut and stored as hay or silage. As a legume, the plant fixes nitrogen so can be used to increase nitrogen in the soil and is a commonly used cover crop. Alfafa is a good source of vitamins, calcium, iron, phosphorus and potassium.

Besides its use as feed, alfalfa has been traditionally used as a medicinal herb for humans. Its seeds and dried leaves can be consumed as supplements, or sprouted as edible alfalfa sprouts. 

Farmers growing alfalfa should consider the following factors when selecting varieties to plant:

Purpose: Decide why you're growing alfalfa. If it's for making hay, focus on varieties that can withstand time and yield a lot. If it's for grazing, pick types that can grow back quickly after grazing. 

Dormancy & Winterhardiness: Check the dormancy rating of the variety you want to plant. Ratings range from 1 (very dormant) to 10 (not dormant). In places with warm winters and little frost, go for varieties with ratings of 9 or 10.

Disease and Pest Resistance: Choose varieties that can at least moderately resist common diseases like bacterial wilt, fusarium wilt, phytophthora root rot, verticillium wilt, and anthracnose.

Forage Yield: It's a good idea to see if a variety has performed well in your specific region before deciding to plant it. This helps ensure a good yield.

Basic Requirements

Alfalfa is adapted to grow in a wide variety of environments but it requires careful management. Alfalfa grows best in deep, fertile, well-draining soils with a pH between 6.0 and 7.0. Alfalfa has a long taproot and quickly depletes nutrients from the soil. If grown in a soil that is poor in nutrients, the crop may require the addition of copious amounts of fertilizer. The vigorous root system means that alfalfa can tolerate dry periods and still give a good yield.

Seeding

Soil should be well prepared before planting alfalfa seeds. A firm seedbed is recommended to improve the stand by improving seed contact with the soil. This helps seeds retain moisture and prevents new roots from drying out. The soil can be firmed before planting by using a roller. The seedbed should also be free of weeds and kept moist. 

Alfalfa crop has tiny seeds and it's crucial to plant them at the right depth.The optimal planting depth varies depending on the type of soil. On medium and heavy soil, plant the seed 1/4 inch (0.6 cm) to 1/2 inch (1.3 cm) deep, while on sandy soil, plant it 1/2 to 1 inch deep. If there's enough moisture, you can plant the seed shallower, but if the soil is dry, you should plant it deeper. While sowing, cover the seeds with soil that is moist enough to promote germination, but not so much that the shoots can't break through the surface. 

General Care and Maintenance

The alfalfa stand should be kept free from weeds. The easiest way to achieve this when the crop is being grown on a commercial scale is with the use of a pre-plant herbicide. There are several of these product available for use on alfalfa. Fertilizer should be applied in accordance with soil test results. Lime, phosphorus and potash are the most important nutrients for a healthy alfalfa stand.

Harvest

Alfalfa is harvested at different times depending on it's intended use. Alfalfa which is cut between thee late bud and early bloom stage generally gives acceptable yields of high quality feed without reducing the quality of the stand. In contrast, repeated harvest of alfalfa which is till in the vegetative stage of growth leads to a reduced stand. In the first year, alfalfa can generally be harvested twice without any detrimental effect on winter survival; once in summer prior to the flowers emerging, and once later in the year with the date depending on location. Alfalfa is usually harvested by combine and baled as hay or cut for direct feeding to animals.

Alfalfa bales

Harvested alfalfa field

CABI Crop Protection Compendium. 2014. Medicago sativa datasheet. [Accessed 05 November 14]. Paid subscription required

Frate, C.A. & Davis, R.M. (2007) Alfalfa diseases and management In C.G. Summers and D. H. Putnam (eds)., Irrigated alfalfa management for Mediterranean and desert zones. Chapter 10. Oakland: University of California Agriculture and Natural Resources Publication 8296. Available at: http://alfalfa.ucdavis.edu/IrrigatedAlfalfa/pdfs/UCAlfalfa8296Disease_free.pdf. [Accessed 05 November 14]. Free to access

Lacefield, G., Henning, J.C., Rasnake, M. & Collins, M. (1997) University of Kentucky College of Agriculture Cooperative Extension Service Publication. Alfalfa: the Queen of Forage Crops. Available at: http://www2.ca.uky.edu/agc/pubs/agr/agr76/agr76.pdf. [Accessed 05 November 14]. Free to access

Undersander, D., Gray, F., Kelling, K. & Rice, M. National Alfalfa and Forage Alliance Publication. Alfalfa Analyst. Available at: http://www.alfalfa.org/pdf/AlfalfaAnalyst.pdf. [Accessed 05 November 14]. Free to access

Undersander, D., Cosgrove, D., Cullen, E., et al. (2011). Alfalfa Management Guide. American Society of Agronomy, Inc., Crop Science Society of America, Inc., and Soil Science Society of America, Inc. Retrieved from https://www.agronomy.org/files/publications/alfalfa-management-guide.pdf [Accessed 13 March 2024]. Free to access