Long term alfalfa productivity depends on successful stand establishment.
By: Karla Hernandez, SDSU Extension, Forages Field Specialist
Achieving a profitable stand of alfalfa is the result proper field selection utilizing proven production practices to ensure germination and establishment.
Establishment of alfalfa seed requires a well-drained soil for optimum production. Poor soil drainage can cause problems with soil crusting which may cause poor soil aeration, micronutrient toxicity, and ice damage during winter.
It is important to remember to take soil samples before planting to determine pH and nutrient status of the field. There are 18 nutrients (macronutrients and micronutrients) essential for alfalfa growth. Some of the most important macronutrients include:
- Phosphorus: helps root growth and increase seeding success. Low fertility soils can be improved with an application of 30 to 50 lbs per acre of P2O5, depending on soil test results.
- Potassium: research suggests that potassium has little effect or influence on improving stand establishment, however, enough potassium should be added to meet the needs of the alfalfa and/or companion crop.
Failure to successfully establish alfalfa could be expensive causing issues with production soil erosion. Some considerations for planting alfalfa include: (1) seedbed preparation; (2) seeding dates; (3) seeding depth and rate; (4) whether or not to seed with a companion crop; (5) 100% alfalfa seedings vs. alfalfa-grass mixtures.
- Seedbed preparation - having a firm seedbed is a critical step to ensure good germination of alfalfa seed. Firm seedbeds will reduce the possibility of planting too deep and will help hold moisture closer to the surface. Packing the soil will help to insure a firm seedbed and good soil moisture retention.
- Seeding dates - determining when to plant alfalfa depends on several factors such as soil moisture and cropping practices. For best results in South Dakota alfalfa should be seeded between mid-April to mid-May.
- Seeding depth and rate - seed should be covered with enough soil to provide moist conditions for germination. Seed placement of ¼ to ½ inch deep is appropriate on most soils at rates from 10 to 25 lb seed/acre.
- Seeding with or without a companion crop - seeding alfalfa with a companion crop such as annual ryegrass, oats, spring barley, or spring triticale can help to minimize weed competition during establishment. However, planting alfalfa without a companion crop allows producers to harvest more alfalfa with higher quality in the seeding year.
- 100% alfalfa seedings vs. alfalfa-grass mixtures - pure stands of alfalfa will produce the highest quality forage and for that reason has the highest demand from the dairy industry. Other producers whose animals’ nutrient requirements are lower may be interested in using alfalfa/grass blends to take advantage of improved persistency while still meeting the nutrient requirements of their livestock. Alfalfa-grass mixtures also offers some advantages such as reduced weed pressure and soil erosion.