Getting a good forage stand can be a tough chore for even the most accomplished growers. Often, the difference between a profitable stand and a thin, weedy one or even a poor stand requiring reseeding boils down to paying attention to details, says Dan Undersander, forage agronomist with University of Wisconsin Extension.
“More than 90% of forage stand failures are due to one of three reasons: low soil pH, loose soil or seeding too deep. Each of these is preventable by the farmer.”
Here are his recommendations for addressing each problem:
● Low soil pH. Alfalfa needs a soil pH of 6.8 and other legumes need 6-6.3. Failure to raise soil pH to optimum levels results in poor germination and slowed seedling growth, which makes the seedlings more susceptible to disease and death. Lime should be applied one year prior to seeding to allow the pH to raise to optimum.
● Loose soil. Soil must be packed around the seed to make good seed-to-soil contact. That allows the seed to take up water from the soil.
“All of us have seen fields where the forage stand was better in the wheel tracks or the headlands – where the soil was packed more firmly around the seed,” says Undersander. “The old-but-good recommendation has been that, if you stand on the field and your shoe sinks more than ¼” into the soil, the soil is too loose for seeding.”
● Seeding too deep. Legume seed should be placed ¼-½” deep in most soils (3/4” in sandy soils). Placing seed deeper may delay or reduce emergence and result in poor stands. Poor seed placement is often visible in new seedings as rows or parts of rows germinate and emerge well while adjacent rows have a poor stand.
“One good test to use when seeding with a drill is to look for seeds on the soil surface after seeding. If the seed is properly placed at ¼-½” depth, some seed will end up on the surface. One should find 8-10 seeds/sq ft on the soil surface. If the number is less, you are likely placing the rest of the seed too deep.”