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Forage: Alfalfa Production

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Publication Number: IS0844

Alfalfa, the queen of hay crops, is a deep-rooted perennial legume that needs a deep, well-drained soil, and it seems to do best on deep loams with open, porous subsoils. Good surface and internal drainage are necessary if alfalfa is to thrive. Soils that are droughty, soils with restriction layers within three feet of the surface, and soils that stay wet during the winter and spring should never be planted to alfalfa.

On good soils and with proper liming, fertilization, weed control, and other good management, stands of alfalfa have been maintained in Mississippi for several years without replanting. Even under conditions where the crop has to be established every two or three years, alfalfa can still produce a profitable hay crop. Research shows that, with good management, annual yields of 5-6 tons of hay per acre can be harvested. This is a total of four or five cuttings per season. You should average 3-4 tons per acre, a total of three cuttings per season, for at least three years before reseeding is needed.

Most alfalfa in Mississippi is grown by dairymen. In recent years, the number of horses has been increased and this has provided a market for higher quality hay than most that is presently produced in Mississippi. Alfalfa hay does have quality that is needed for horses. It is also a popular hay for beef producers in areas where the hay is available.

Lime and Fertilizer Requirements
Alfalfa does best on soils with a pH of 6.5 or above, containing a high level of plant nutrients. Take soil samples to determine the lime, phosphate, and potash needs. Most Mississippi soils need lime, and you should apply it before or during seedbed preparation. If no soil test is available, apply two tons of lime per acre, except on the black prairie soils, and 500 pounds of 0-24-24 or its equivalent per acre at planting time. Apply the equivalent of 2 to 3 pounds per acre of actual boron with establishment fertilizer or apply it alone as Solubor. This much fertilizer should carry fall-seeded alfalfa through the first summer. However, you should take soil samples by the second harvest and additional potash may be needed, especially on sandy soils. Thereafter, annual applications of 500 pounds per acre of 0-15-30 or its equivalent plus 2 to 3 pounds of actual boron will usually be needed. On good alfalfa-growing soils, it may be best to apply this fertilizer after the first harvest since the first harvest is usually rank and may be more subject to lodging with earlier applied fertilizer. Also, applying fertilizer after the first harvest helps carry more potash into fall growth. This potash helps the plants to be more winter hardy the following winter. Take soil samples annually to determine specific fertility needs.

Alfalfa produces adequate nitrogen for its use where soils are properly limed and fertilized and the seed are inoculated with the proper culture at seeding time.

Select a good variety and seed as early as September 1 and no later than October 15. Spring seeding is not always successful in the South because of weed competition, but usually a fall seeding competes with the weeds. See MSU-ES Information Sheet 1168, Forage Types, Varieties, Planting Dates, and Rates, and Information Sheet 1083, Inoculating Forage Legumes, for more information.

Alfalfa Weevil Control
You must control the alfalfa weevil to prevent economic loss and stand reduction. The acceptable method of control requires the use of one or more recommended insecticides applied early, based on the number of larvae per stem. To determine larval numbers, scout fields weekly (starting in mid-February). If larval populations reach 1 to 2 per stem, apply an insecticide using 10 to 20 gallons of water per acre.

For the major part of the area where alfalfa is grown in the southern region, Furadan 4 Flowable has become an accepted chemical for controlling the alfalfa weevil. It provides contact and systemic controls, has long residual effectiveness against alfalfa weevil larvae, and can be effectively applied earlier than other insecticides. There is a 7-day waiting period before grazing or cutting for each 1/2 pint (.25 lb) of Furadan 4 Flowable used per acre. It usually takes one pint (.5 lb) per acre to provide contact and residual control, depending on weevil population. If weevil larvae damage reappears on regrowth following harvest, temperatures should be warm enough to get good control with a material such as malathion. For a list of other insecticides, refer to MSU-ES Information Sheet 722, Control of Insects Attacking Forage and Pasture Crops, available at your county Extension agent's office. Read all labels that come with the chemicals, and follow directions given on the label.

Cutting Management
Let alfalfa seeded in the fall reach 10 to 25 percent bloom the first spring before harvest. However, if lodging starts to occur, it may be best to harvest somewhat earlier. The following cuts should be made at 10 percent bloom or before the new crown buds at the base of the plants reach a height to be clipped when harvested. The time period between harvests usually ranges from 30 to 40 days. In the second and succeeding seasons, the first harvest may be taken in the full bud stage, with other harvests being made at 10 percent bloom or before crown buds advance. Always allow the last growth in any season to grow and store the full amount of food reserves in the tap root before being killed by freezing temperatures. This provides the energy for the new plants to grow the following spring. Usually the last cut should be made no later than mid-September in north and no later than mid-October in south Mississippi. After complete kill by cold, the remaining frosted growth may be removed by harvesting or grazing.

Chemical Weed Control
Controlling weeds is sometimes a major problem in growing alfalfa, especially on early fall and spring seedings. Weeds can emerge in such numbers that they reduce the alfalfa stand. In some cases, you can get a more uniform and productive stand of alfalfa by using herbicides to prevent weed problems. However, most seedings made between September 1 and October 15 will not require a herbicide to control weeds.

There are several preplant and postemergence herbicides for weed control in alfalfa. Current information on chemical weed control can be found in the forage section of MSU-ES Publication 1532, Weed Control Guidelines for Mississippi, and in Extension Information Sheet 945, Forage Weed Control in Pastures. County Extension agents can assist with this information when needed.

The information given here is for educational purposes only. Reference to commercial products or trade names is made with the understanding that no discrimination is intended of other products that also may be suitable.

By E. Lamar Kimbrough, Ph.D., Extension Agronomist, and Douglas M. Gaydon, Ph.D., Extension Entomologist

Mississippi State University does not discriminate on the basis of race, color, religion, national origin, sex, age, disability, or veteran status.

Information Sheet 844
Extension Service of Mississippi State University, cooperating with U.S. Department of Agriculture. Published in furtherance of Acts of Congress, May 8 and June 30, 1914. Ronald A. Brown, Director

Copyright by Mississippi State University. All rights reserved.

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