Corn, Soy Planting: Midwest and Northern Plains Wait for Soil Temps to Rise – DTN

No, you didn’t mix up the calendar pages. It’s mid-April, and some Midwest farmers are watching snow pile up on their fields this week.

As the pace of planting slips further behind schedule, the temptation to plant seeds into frigid, wet soils grows.

“I know the calendar says plant now, but the soil does not,” cautioned University of Missouri plant pathologist Kaitlyn Bissonnette.

With the exception of the dry Southern Plains and mild Southeast, most of the country should not expect much relief soon, added DTN Senior Ag Meteorologist Bryce Anderson.

“The pattern that we’re in is going to continue through the rest of this month and well into May, with the Northern Plains and Midwest having below-normal temperatures and above-normal precipitation,” he explained. “Combine the lingering influence of La Nina with the effect on the pattern of persistent far northern latitude high pressure re-routing the prevailing winds from the polar regions, and you get the kind of features that we have going on.”

Here’s quick review of the many pitfalls that await farmers who succumb to planting in cold, wet soils, courtesy of Extension scientists across the country:

GERMINATION AND SEEDLING PROBLEMS

Seeds, meet your worst enemy: frigid water.

Fifty degrees Fahrenheit is the goal for soil temperatures at planting — but that’s only half the equation. Warm weather for at least a few days is critical to keep soil temperatures up, particularly in the face of moisture. If corn seed takes in cold water in the first 48 hours, a phenomenon known as imbibitional chilling occurs, and can damage and kill a seedling, University of Nebraska crop scientists explained in a CropWatch article. Link here.

After that, corn seeds can wait out cold conditions fairly well, but a good fungicide seed treatment is critical, Bissonnette said. “A lot of seedling diseases require cool and prolonged soil temperatures,” she noted. “Pythium is the biggest risk right now.”

For soybean seeds, the risk of imbibitional chilling drops after just 24 hours, but they are actually more sensitive to cold and may not tolerate sitting in cold soils as well as corn seed, a CropWatch article from last spring reminds us. Link here.

Some farmers are starting to push soybean planting dates, based on solid research connections between early planting and higher yield potential. Link here.

“But from a pathology perspective, you have to balance the yield return of early planting and disease risk,” Bissonnette cautions. Sudden death syndrome is a growing problem for Midwest soybean growers. It infects fields early in the growing season and favors cool, moist soils.

If you’re curious how your corn and soybean seed will handle cold, wet soil conditions, consider this cold germination test from the University of Nebraska. Link here.

CROP SUBSTITUTIONS

From the University of Minnesota, Extension Agronomist Jochum Wiersma warns that the window for small-grains planting is shrinking as April wears on. Link here. Wheat, barley, and oats need cool weather early in the season to maximize yield potential. As planting is pushed deeper into April and May, small grains will be forced to do their early season growing in warmer conditions.

“This forces development along faster and causes the plant to have less time to grow. Plants end up with fewer tillers, smaller heads, and fewer and smaller kernels per head, cutting into our yields,” Wiersma explained.

Growers can “partially offset” this growing yield loss by increasing seeding rates, but some growers may have to rethink their planting plans if the weather continues to keep growers out of the field into the month of May.

Some soybean growers might start to rethink their maturity group selection as spring wears on. But research from University of Wisconsin Extension Soybean and Small Grains Specialist Shawn Conley suggests that dropping to an earlier-maturing soybean variety is only necessary when planting dips into June. Before that, longer maturity group beans can actually help maximize your yield, Conley said. Link here.

Similar research exists for corn seeds, from Purdue’s corn agronomist, Bob Nielsen. He found that, for Indiana and Ohio farmers, the most common hybrid maturities will adjust to a planting date throughout the month of May. Only after that does he recommend considering a faster-maturing hybrid. Link here.

However, for more Northern Midwest growers, an earlier switch to shorter maturities can be necessary, depending on your grain-drying costs, this Michigan State University article notes. Link here.

For more thoughts on how to handle late planting in corn and soybeans, see this trove of research aggregated by Nielsen. Link here.

COMPACTION WOES

Wet soils and farm machinery don’t mix well, cautions this Penn State article. Driving on soaked fields causes rutting and soil compaction. Link here.

High axle loads (10 tons or higher) can cause compaction so deep in the subsoil profile that even thawing-freezing cycles and cover crops cannot repair it easily, Ohio State warns. Link here.

ACTIONABLE INSIGHTS:

  • Check your soil temperature and wait for 50 degrees Fahrenheit with a mild forecast ahead.
  • Your small-grains planting window closes soon.
  • Don’t switch maturity groups for corn and soybeans until planting pushes deeper into May and June.
  • Don’t drive on wet soils and if you must, keep axle loads below 10 tons.

Emily Unglesbee can be reached at Emily.unglesbee@dtn.com

Follow her on Twitter @Emily_unglesbee

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