Consider Previous Crop Before Seeding Alfalfa

Dry growing conditions in 2012, followed by an ongoing drought, have caused some growers to question whether or not to rip up new alfalfa seeding or established stands that were injured. We’ve been telling farmers to manage alfalfa based on winter injury, and honestly, it’s taken longer than usual to see just how much damage has occurred.

Usually at this time of year, our alfalfa is waking up and ready to stretch from its long winter nap. But, our weather has been anything but typical!  Last Sunday a snow storm hit the Dakota, closing Interstate 94 from Bismarck through North Dakota. There’s also snow in the three-day forecast for Alexander, Iowa, home of Latham Hi-Tech Seeds.

Snow that falls in mid-April can’t last long though, right?  We know spring planting season will soon be underway, and we want to do all that we can to help you set up seeding for success. Here are some things to take into consideration if you decide to reseed alfalfa:

  1. Re-seeding if you have winter injury has the potential for autoxicity, depending on age and health of the stand. Autotoxicity in alfalfa is the process by which established alfalfa plants produce a chemical compounds that escape into the soil and reduce competition.  This toxic compound can reduce the establishment and growth of new alfalfa if seeded too soon following the old stand.Take autotoxicity into consideration if you plan to re-seed in seeding that didn’t survive winter. It’s generally not recommended to re-seed or interseed alfalfa especially into a well-established stand that may have winter kill damage or has thinned over time. See this autoxicity risk worksheet to help assess your risk factor.
  2. Seed bed preparation is key. A firm seedbed, before and after seeding, allows for consistent seed depth and good soil-to-seed contact.
    1. If you’re seeding alfalfa where corn was planted in 2012, I would try and reduce particle size, such as disking the ground.  A couple of passes will help the stalks breakdown better. Dry conditions last fall made it difficult to get good residue breakdown, as moisture is important to help disk cut material, and also important in the biology of decomposing old material. This spring, try and reduce particle size, and then incorporate and mix residue into soil from chisel plow or moldboard plow to establish that nice seed bed. As always, we have to consider slopes. Leaving some residue helps prevent erosion, but I like smaller particle sizes as they seem to absorb moisture better from a hard rain.
    2. Once again, I generally prefer smaller residue particle sizes as I believe it also helps get better seed-to-soil contact. Make sure corn stalks are chopped well.  Otherwise, seed can be buried under a large particle of corn stalk or the seed just sits on top of the soil.
    3. Seed alfalfa with a brillion or seeder with press wheels if possible. It helps to ensure best seed-to-soil contact. Although, I know there are lots of growers who have had good luck seeding alfalfa with a grain drill and a drag. Do whatever works best for you!
  3. Take soil tests in alfalfa fields. I’m a big fan of soil testing because it provides a benchmark for soil health and helps us better understand fertilizer needs. One of the biggest concerns with alfalfa production is the soil pH, or its acidity level. If the soil’s pH is marginal, we can begin to correct it more rapidly by applying something Pell lime or something similar. Latham has products designed to handle specific environmental challenges that may be present on your acres, so click here for product considerations ranging from sandy to salty soils.