By Karla A. Hernandez
SDSU Extension Forages Field Specialist
Planning for the growing season this year has been a little different than in previous years. The winter season seems not to give up and has producers wondering when they would be able to access their fields. Here is a bit of information for those producers that are considering planting alfalfa this year.
Establishment of alfalfa seed require a well-drained soil for optimum production. Achieving a profitable stand of alfalfa is the result of proper field selection utilizing proven production practices to ensure germination and establishment. 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 ALWAYS take soil samples before planting to determine pH and nutrient status of the field. Overall, there are 18 nutrients (macronutrients and micronutrients) essential for alfalfa growth. Some of these nutrients include:
• Phosphorus: helps root growth and increase seeding success. Low fertility soils can be improved with an application of 30-50 pounds per acre of P2O5, depending on soil test results.
• Potassium: research suggests that potassium has little effect or influence on improving stand establishment, however, adequate potassium should be added to meet the needs of alfalfa and even a 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 percent 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. This all depends on weather conditions as well. This year might be safe to say that seeding alfalfa in mid-May might be the best option for producers.
• 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 percent 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.