Early Planting Seed Selection

Seed Selection Tips for Early Planting

Matt Wilde
By  Matthew Wilde , Progressive Farmer Crops Editor
(Joclyn Bushman, Iowa Soybean Association)

More farmers are forgoing the calendar to plant soybeans and corn as soon as weather and soil conditions allow in hopes that earlier planting will boost yield. But, the practice isn't without risk.

For those pushing the planting date envelope, there are several things to consider when selecting seed.

Choosing corn hybrids and soybean varieties with high emergence ratings is a must, emphasize seed industry officials and agronomists. So is adding seed treatments to help seeds and young plants survive in cool, damp soil and fend off diseases and pests.

There are also seed-selection considerations unique to each crop and tillage system. Matt Essick, Pioneer agronomy manager for the Dakotas, Minnesota and Wisconsin, says picking the right seed and traits is vital to maximizing the plant's potential, which is the driver of early planting.

"In my 20 years in the seed industry, I do see early planting as a trend that's here to stay," Essick says. "It seems like we only get so many days to plant when soil conditions are really good. I would hate to pass up a day waiting for a calendar date."

Decades ago, it was common practice to wait to plant corn and soybeans until soil temperatures were well above 50°F to hasten and improve emergence. In much of the Corn Belt, that usually occurred in mid-May or later. (Ideal planting windows vary throughout the country).


Studies show waiting too long to plant can cost yield.

A multistate study led by Shawn Conley, University of Wisconsin soybean specialist, indicates soybean yields decrease 0.2 to 0.5 bushels per acre (bpa) per day when seed is planted after April 25. Soybeans planted in mid-April tend to yield 5 to 10 bpa better than mid- to late-May plantings, Conley explains.

Essick says Pioneer early-corn-planting studies show yield responses between 0 to 17 bpa for mid- to late-April plantings versus early May.

Iowa State University Extension pegs the optimum window to plant corn is between April 11 to May 18, though seeding earlier during the time frame avoids the "slippery slope" of rapidly reducing yield potential.

"Farmers need to balance the (yield) advantage of planting early with the risks," says Emerson Nafziger, a University of Illinois crop-production professor emeritus. Frost damage and imbibitional chilling for corn are two examples. However, he says seed companies have geared breeding programs to offer more seed options to better handle early-season environments, which can include big temperature swings and heavy rains.

"You can't sell seed without expecting that people will plant early," Nafziger says.


Most soybeans planted in the Midwest are indeterminate varieties. In the South, determinate and indeterminate varieties are planted. However, a lot of southern acres have moved to indeterminate varieties.

The onset of reproductive growth results in the termination of vegetative growth in determinate varieties, according to information provided by North Carolina State University. Indeterminate varieties start flowering several weeks before they terminate vegetative growth.

Most soybeans planted in the U.S are indeterminate varieties and photoperiod sensitive. By planting as early as possible, soybean plants absorb more sunlight. That spurs vegetative growth and flowering during the reproductive period. More flowers equal more nodes, which means more pods and soybeans.

Here are three soybean-variety selection tips when planting early:

1. Corey Prosser, LG Seeds sales agronomist in Ohio, says picking high-yielding varieties that emerge and grow fast is best if planting early. Cooler soils early in the planting season can delay emergence.

LG Seeds rates soybeans for emergence and early vigor on a one to nine scale, with nine being the best. Prosser recommends farmers pick varieties on the high end of the scale if they plant early. That's even more important in early-planted, no-till fields and cover-crop acres, he says, which tend to be colder earlier in the season than tilled fields.

"You want soybeans to pop out fast," Prosser explains. "However, just because a variety emerges fast doesn't mean it grows fast. You want both."

2. Select the longest-season varieties suitable for the climate and farm. Hans Kandel, North Dakota State University (NDSU) soybean specialist and agronomist, says planting early -- usually the first 10 days of May in North Dakota -- allows farmers to plant a slightly higher maturity group. He says NDSU studies show for every tenth of a point increase in maturity group, yields increase 0.7 bpa, on average.

"By pushing that maturity, you can gain yield," Kandel says. "In our case, I'm talking about going from a 0.5 to 0.7 maturity group. It depends on where you are at in the state or country, and farmers still have to be mindful of the first fall frost date."

3. Protect seed and seedlings. Most soybean seed is treated that goes into the ground today. For early-planted acres, agronomists recommend the seed treatments include fungicides that protect against early-season diseases such as Pythium, Phytophthora, Rhizoctonia, Fusarium root rot and sudden death syndrome.


Planting corn early can lead to earlier canopy development for improved photosynthetic efficiency and earlier pollination. An earlier start to grain fill could mean less heat and water stress on the corn crop in the midsummer. Less plant stress ultimately boosts yields.

Here are three corn seed-selection tips for early planting:

1. Essick recommends picking hybrids best suited for specific geographies with high-stress emergence scores. Pioneer's rating is one to nine, with nine being the highest. Essick doesn't recommend going below a six or seven for early-planted corn.

"It (corn seed) will potentially have to tolerate some cool, wet conditions," he continues.

In no-till and high-residue fields, Essick encourages farmers to also pick hybrids with high-residue suitability ratings.

2. Prosser says early planting allows farmers to select fuller-season hybrids. "I have farmers that may have chosen 112-day corn in the past, but early planting allows them to pick 114- to 116-day corn," he adds, which typically means higher yields.

3. Pythium is a concern for early-planted corn, Essick says. Seed treatments are critical to protect against that disease and others. No-till fields with more residue can potentially lead to more foliar diseases, too.



-- Learn about Iowa State University Extension planting date considerations at https://crops.extension.iastate.edu/…

-- Follow the latest from Matthew Wilde, Crops Editor, by visiting the Production Blogs at https://www.dtnpf.com/… or following him on Twitter @progressivwilde


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