Wet forecast intensifies seeding decisions

With periods of freezing and thawing over the winter and long-range forecasts for above-normal precipitation, forage planting this spring will present challenges for growers in the Upper Midwest. However, farmers can take several measures to manage such challenges to achieve the best stands possible.

Lynn Grooms

Grooms Communications

Lynn Grooms of Grooms Communications is a freelance journalist specializing in agriculture.

First, consider timing and field conditions. Shelby Gruss, Iowa State University (ISU) Extension forage specialist, suggests planting alfalfa soon after the last killing frost so that it has time to establish and gain a competitive edge over other plants for sunlight and weed suppression. In their article, “Alfalfa Seeding Recommendations,” Gruss and Joshua Michel, ISU field agronomist in northeast Iowa, note that planting alfalfa too early can expose young stands to damaging frost, while planting too late can lead to greater potato leafhopper and weed pressures.

According to the National Oceanic and Atmospheric Administration’s (NOAA) Climate Prediction Center (CPC), the outlook through March shows above-normal precipitation in the Upper Midwest. It’s the same story for March through May. Wet springs stress alfalfa and small grains. However, paying attention to 30-, 60- and 90-day forecasts helps because forecasts can change, says Kevin Jarek, regional crops and soils educator for the University of Wisconsin Extension.

Alfalfa and small grains in well-drained fields with good fertility, excellent tilth and pH levels greater than 6.8 will probably do fine. Alfalfa can be planted even in wet conditions in those types of fields. Farmers sometimes refer to those as Tier 1 fields. Tier 2 fields have poorer drainage, are not quite as fertile or may require a pH adjustment. If wet conditions pose a problem in Tier 2 ground, the farmer may consider planting less-expensive alfalfa seed or move seeding to Tier 1 ground if alfalfa seeding is absolutely necessary, adds Jarek.

Given forecasts for a wet spring, he recommends farmers plant fungicide-treated seed. In addition to protecting seed from soilborne and seedborne fungi, seed treatments suppress blights that can arise later in the plant’s growth stage.

Gruss recommends planting disease-resistant alfalfa varieties. While such varieties are more expensive, stands will be healthier for a longer period. Farmers can evaluate varieties using the National Alfalfa and Forage Alliance’s annual “Alfalfa Variety Ratings – Winter Survival, Fall Dormancy and Pest Resistant Ratings for Alfalfa Varieties” publication or use their online searchable database. When selecting a variety, prioritize those rated highly resistant to the disease or pest of concern. A highly resistant rating means only about 50% or more of plants are resistant, so this strategy helps hedge risk rather than eliminate disease or pest pressure.

Small-grain considerations

Farmers who are considering planting small grains for forage can plant early in the spring. Margaret Smith, forage agronomist at Albert Lea Seed in Minnesota, says spring-seeded small grains with good cold tolerance can be planted as soon as farmers can get into the field. No-till planting into light crop residue allows for earlier planting. Small-grain seeding rates for forage production are the same or slightly greater than for grain. Seeding rates can be increased 10% for forage production. There is less time for tillering when planting spring-seeded small grains compared to winter grains, so farmers need to start with a slightly higher planting rate when planting in the spring to achieve an economic optimum number of seedheads.

Smith shares the accompanying Table 1, which shows the optimum seeding rates for small grains in the Upper Midwest.

The University of Minnesota Extension also provides a general formula for calculating seeding rate:

Seeding rate (pounds per acre) = [(desired stand in plants per acre) / (1 - expected stand loss)] / [(seeds per pound) x (percentage germination)]

Calculate the seeding rate for each seed lot and calibrate the drill accordingly.

The University of Minnesota Extension provides this example for calculating wheat seed planting rate:

Desired population = 1.25 million plants per acre at harvest
Historic field stand loss = 10%
Seed lot germination = 95%
Seed lot seed count = 15,000 seeds per pound
Calculate:
1. 15,000 x 0.95 = 14,250 viable seeds per pound
2. 1,250,000 seeds x 110% = 1,375,000 viable seeds needed per acre
3. 1,375,000 seeds divided by 14,250 seeds per pound = 96.5 pounds per acre seeding rate, or 28 seeds per square foot

As much as 20% of small-grain seeds may not germinate. Different bags may not contain seeds from the same seed lot, so one can’t necessarily depend on a standard seed count; this is why farmers should use average- seeds-per-pound calculations, says Smith.

Once a farmer decides which seeds and at what rate to plant, they need to consider planting methods such as no-tilling, traditional tilling, broadcast seeding or precision planting. In 2020, Michigan State University (MSU) researchers wrote an article that focused on a study about how optimum seed depth, seed-to-seed spacing and row spacing can affect yields.

Led by Manni Singh, MSU cropping systems specialist, the research team compared wheat planted with a conventional drill versus a precision planter. They were looking to see if the metering system on a vacuum planter could achieve more uniform seed placement (depth and singulation) compared to a conventional drill.

The researchers found that based on first-year data, the precision planter could increase seed depth uniformity to as much as 60% and plant-to-plant spacing to as much as 20%. This led to a 10% yield increase when compared to the conventional seed drill. One of the most important benefits of the precision planter when compared to the drill was its ability to control seed depth and precise metering, especially when planting as many as 1.5 million seeds per acre, the research team wrote.

Preliminary research showed that using a precision planter can increase yields, but that alone might not be enough to make farmers replace their old drill.

“It all comes down to cost-benefit, so a detailed economic analysis would be warranted,” the article states. “If the industry can come up with a planter that does an excellent job with singulation, depth control, row spacing and can plant multiple crops, farmers will be more willing to pay for it.”

Several European-based companies have developed precision seed drills, with some drills significantly reducing seed rates. Please see the links below for more information.

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