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 Recharge areas should be seeded to alfalfa. Deep-rooted high moisture use crops, such as alfalfa, prevent the buildup of groundwater, lower the water table, dry out the subsoil and restore the water storage capacity of the soil (Brown et al. 1982). Alfalfa roots to 6 m (20 ft) in four to five years and uses over 760 mm (30 in.) of water per year.

Recharge areas identified during a salinity investigation should be seeded to alfalfa. On average, recharge areas are about three to five times larger than their saline seep. The best time for seeding alfalfa is early spring. If wind erosion is not a concern, alfalfa should be seeded without cover crop because competition with cover crops will reduce the alfalfa stand. If cover crops are needed, reduce their seeding rate to half the normal rate.

Alfalfa should be seeded as shallow as possible into a firm, moist seed bed at rate of about 7 kg/ha (6lbs/ac). It can be seeded using any conventional seeder. Hoe drills often give the most effective results because of good depth control and packing capability. However, in loose soil, disk drills may place the seed too deeply, and in very firm soil, they may leave the seed on the soil surface. Both conditions result in poor germination. Other seeding equipment also produces satisfactory results.

Phosphorus, potassium and sulphur are also important nutrients for optimum alfalfa production. The soil test should be performed to determine nutrient needs. Alfalfa requires 5 kg of phosphorus per tonne of yield (10 lbs/ton). This nutrient is very immobile in the soil, so application prior to seeding is recommended. It should be deep banded in the fall prior to planting alfalfa in the spring. The phosphorus application should meet the alfalfa's requirements for the life of the stand. For example, if the target yield is 1800 kg/year (2 tons/year) and the life of the stand is 5 years, then 45 kg (100 lbs) of phosphorus should be available.

When alfalfa is seeded in a recharge area, it usually takes five years to lower the water table in the associated saline seep. Once the water table is lowered to an acceptable level, the recharge area may be planted to cereal crops for a few years and then back to forage.

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For more information about the content of this document, contact Karen Raven.
This document is maintained by Laura Thygesen.
This information published to the web on February 12, 2004.
Last Reviewed/Revised on August 24, 2017.