Ken Ferrie: 7 Tips To Overcome Moisture Concerns At Corn Planting

Studies conducted by Farm Journal Field Agronomist Ken Ferrie show any hybrid’s yield can vary by 6 bu. to 12 bu. per thousand ears, depending on your management practices. One of the key ones is the quality of your planting pass. 

This season, too little moisture as well as too much moisture are impacting the corn planting process across the country.

A look at the U.S. map below shows that much of the Eastern Corn Belt has sufficient or too much moisture, while portions of Iowa, Nebraska, Missouri, Kansas and eastern Colorado have moisture deficits. Check out the article by U.S. Farm Report's Tyne Morgan: It's Scary Dry in the Western Corn Belt, But a Drastically Different Story in the East This Year

As you navigate soil moisture levels this spring, here are seven tips Ferrie says to consider:

1. A perfect stand needs a perfect seedbed. Here are some of the big-picture parameters to keep in mind: adequate moisture at planting depth; soil temperature of 50˚F or higher; seed-to-soil contact, with no air pockets around the seed; and no residue at planting depth or in the furrow.

2. Plant by temperature, not by calendar. "Seed corn is very sensitive to soil and soil water temperatures that are below 50°F at planting and during the first 48 hours afterwards," says Ferrie. 

He says soil water temperatures above 50°F gives seed cell membranes elasticity, allowing them to stretch and expand appropriately as they take on moisture. 

The opposite extreme occurs when temperatures are below 50°F. Cold seed cells have little elasticity, so as they take on moisture instead of swelling, they tear.

“This is what we call seed chilling, and it can take 7% to 10% out of your corn stand,” Ferrie says. 
This can make for a tough call when planting conditions are perfect but the soil is too cold.

“Your decision depends on how many acres you farm and how many acres you can plant per day — a 10% to 15% drop in ears in April might be the lesser of two evils compared to planting corn in June,” Ferrie says. “But if you want a perfect ear count, avoid seed chilling.”

3. Consider seed quality. “Severe pericarp damage means tears in the embryo axis, and that seed may not germinate if it’s chilled,” Ferrie says. “Moderate pericarp damage means cracks in the pericarp in other parts of the seed. Cracks in the pericarp let water enter faster, increasing the risk of chilling.

"Round seed is most susceptible to pericarp damage; but we see it in all sizes and shapes," he adds. "Seed with cracks in the pericarp performs OK in warm soil, but it might have a problem in cold, wet conditions.”

Planting in cold conditions can cause seed quality issues to multiply. Ideally, plants should emerge in a 48-hour window, within five days.

“If corn takes 30 days to emerge, seed planted spike-down will likely emerge later and produce poor ears,” Ferrie says. “It usually takes 24 to 48 hours for the mesocotyl to make a 180˚ turn and reach the surface, but in cold soil it can take 10 days or more. Seed with poor hybrid vigor and low-cold and saturated-cold germination scores – which we’ve seen this year – will struggle in these conditions.”

4. Plant at uniform depth. Uniform seed depth helps ensure uniform temperature and moisture. It requires a level seedbed.

“Conventional tillage has the upper hand, if you don’t create a cloddy mess,” Ferrie says. “If you use vertical primary tillage in the fall, fracture soil uniformly across the width of the implement because the vertical harrow you run in the spring levels only the surface. Without full shattering, fields that look level on top will feel like speed bumps to the planter.“

In no-till, Ferrie says, level the seedbed with row cleaners.

Strip-till requires applying the right amount of down-pressure to hold the row unit in the ground. ”That will be easier if you stay centered on the strip,” he says.

5. Consider moisture availability. “Never plant corn into dry soil, hoping for a rain,” Ferrie says. “Either plant deeper to reach moist soil, or wait for rain to fall. Getting caught in dry planting conditions tends to occur if you’re not ready when fields dry out or if you do horizontal tillage too far ahead of planting. No-till and strip-till have less tendency to run into dry planting conditions.”

On the flip side, don’t muddy corn into the field. “When it comes to muddying in corn, that is always a red light,” he says “We only mud corn in for insurance purposes.”

The only way to know whether you’re planting into moisture is to stop and dig behind the planter. Ferrie says to do that multiple times in each field.

“Everyone, stop and dig multiple times a day to ground truth that you are staying in the moisture,” he implores. “The trick is to get into moisture and then to hold onto that moisture."

6. Close the furrow. “One secret of not running out of water before germination is to firmly pack soil around the seed with your planter’s closing wheels,” Ferrie says. “Firmly packing soil, with no air pockets, keeps moisture from leaving the furrow so it is present to trigger germination over the next three days.” 

Closing wheels must be centered over the row and stay there. “Replace worn bushings prior to planting season,” Ferrie says. Spoked closing wheels make it easier to close the furrow and avoid smearing soil in moist conditions.

“Be careful not to let the soil dry out,” he adds. “Some spoked wheels have more firming action, which helps prevent the soil from drying.”

7. Avoid sidewall smearing. “Sidewall smearing causes problems with seed/soil contact and root development,” Ferrie says. “It most often occurs in no-till, but it also occurs in conventional tillage if the soil is too wet for the amount of down pressure being used.” 

Slicing across the furrow, you should see no seams or signs of how the seed was placed in the trench. “If cross-sectioning reveals a seam, reduce down pressure and see if it disappears,” Ferrie says.

If you can’t eliminate sidewall smearing without giving up consistent depth, you must make adjustments. “With technology, you can adjust down pressure by the row and by the foot, automatically, as you cross different soil conditions,” Ferrie says. “If you don’t have the technology, adjustments will be for the whole planter and the entire field, so make your settings in the toughest area.” 

Be especially alert for sidewall smearing if you run a high-speed planter. “The faster you go, the more row units want to come out of the ground, increasing the need for more down pressure.” Ferrie says. “If slowing down helps, you may only need to do it in the areas giving you trouble. But if reducing down pressure and slowing down doesn’t help, the field is too wet to plant.”

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