Establishing a successful spring alfalfa stand takes planning and preparation. The plan to plant alfalfa in a field should be made one to two years in advance of when it is to be seeded. Alfalfa plants prefer better drained fields and soils with a pH between 6.5 and 7.5. The labels of herbicides that are applied one and two years prior to alfalfa seeding should be carefully read as many commonly used herbicides have rotational restrictions for alfalfa seeding longer than 10 months. Ideally a new stand of alfalfa should not follow an old stand of alfalfa due to the potential for autotoxicity.
Soil tests should be taken one to two years prior to seeding alfalfa, and appropriate amounts of fertilizer and soil amendments should be applied prior to seeding to allow for incorporation. Low soil pH (below 6.5) has the potential to limit nutrient availability and thus crop yields; therefore, applications of lime to bring pH up to 6.5 is important for long-term alfalfa production. Two key nutrients that alfalfa uses are phosphorus (P) and potassium (K); therefore, a selected field low in P and/or K should have nutrient levels built prior to seeding, and the use of an aggressive fertilizer program following seeding can be beneficial.
Good seeding practices include helping to ensure excellent seed to soil contact in a firm to hard seedbed that is weed-free. Several different implements can be used to seed alfalfa. Residue management is critical with some of them and depending on previous crop, residue may need to be addressed the prior fall to provide the best spring seedbed. Of all the things that are required to establish an excellent stand of alfalfa, seeding at 0.25 - 0.50 inch deep (0.75 inch on sandy soils) and packing the soil to help ensure excellent seed to soil contact is the most important. If the seed is properly placed, packing a soil too much is difficult. Prior to seeding, a good rule of thumb to help assure a firm seedbed is to walk across the soil and have your footprint not be deeper than a half inch.
When selecting an alfalfa product, make sure you select one with the appropriate fall dormancy and winter hardiness to survive in your geography. Next if you have any concerns with a specific disease or weed, selecting based on disease scores or a Roundup Ready® alfalfa product can help with stand life and productivity. Channel® brand has a broad offering of alfalfa products to fit most needs, from conventional to Roundup Ready® alfalfa to HarvXtra® Alfalfa with Roundup Ready® technology, which provides better digestibility when compared to other alfalfa products harvested at the same maturity.
Seeding rates of a clear stand of alfalfa should be between 12 and 14 lbs/acre of pure live seed with good to excellent seedbeds and planting techniques. Seed should be treated with a fungicide to help keep seedlings healthy and an inoculant that provides the right strains of rhizobium for productive nodule development and nitrogen production.
Companion crops are sometimes warranted; however, they can add significant risk to having a perfect long-term, high-yielding alfalfa stand. Two situations where companion crops make sense are when a forage crop is needed near term as forage production can be boosted on that acre during the seeding year and when a cover crop is needed on some high risk erodible ground. A cover crop, like small grain, should be used only where needed and seeding rate should be reflective of the erosion risk, often between 0.25 - 0.50 times normal seeding rate. Killing the cover crop when it is 4-6 inches tall allows for protection from erosion and strong seedling establishment.
The first production year of a spring-seeded crop should have 20-25 healthy plants per square foot. Given that a percentage of plants die from seeding year to first production year, ideally 30-50 plants per square foot should be present the seeding year.
Management practices for seeding alfalfa. Agronomy Advice. Channel.com. http://www.channel.com/agronomics/Documents/AgronomicContentPDF/ManagementPracticesforSeedingAlfalfa.pdf