KEY POINTS

• The first 28 days of a corn plant’s life are critical to its final yield potential.
• Attention to GDUs, seeding depth and soil conditions help crops start strong.
• Make sure corn plants have sufficient fertility in the root zone by the V2 to V3 stage.

The first 28 days after planting are critical to building a corn crop’s yield factory in the growing season. “We know slower emerging corn plants make fewer bushels than early emerging plants. That’s been proven,” says AgriGold Agronomist Leslie Lloyd. “If you get off to a slow start, you can still produce an average to above-average crop, but it’ll be an uphill battle.”

He offers advice for optimizing the first 28 days, positioning farmers to unlock the full potential of their acres.  

Let GDUs guide planting decisions

Each season, Lloyd says corn farmers are faced with a dilemma: Planting early usually pays dividends in yield, but it also comes with an elevated risk of cool, wet soil leading to uneven emergence.

“Farmers have less room for error this season, so it’s even more critical not to make mistakes like planting a day too early or when the field is too wet,” Lloyd says. “Pay attention to details and err on the side of caution.”

To mitigate risks associated with early planting, Lloyd advises paying attention to the accumulation of growing degree units (GDUs). “It takes about 120 GDUs for a corn plant to emerge,” Lloyd explains. “If you’re debating whether to plant, look at the GDU accumulation for the last three days and the next three days. If it’s not accumulating the 120 GDUs that corn plant needs, don’t plant.”

Don’t plant too shallow

When it comes to emergence, a farmer wants the time from when the first plant shoot emerges to the last one appears to be as short as possible. How do we get more of those plants out of the ground early? “A lot of that comes down to planting depth,” Lloyd says.  

“Farmers go to huge expense with their planters to get perfect everything in terms of seed singulation and drop for ideal spacing,” Lloyd says. “But what the planter cannot do is set to the ideal depth when you first pull into the field for things like variation in tillage, field size or crop rotation. As planting technology advances, we often forget the basics, like the fact soil temperatures and moisture are more uniform deeper into the soil.”

Farmers aren’t making a mistake by planting deeper, Lloyd says, referencing his studies on the topic. “A far more common mistake and reason for replanting is planting too shallow,” he says.  

“There’s a lot of temperature fluctuation in the top 1.5 inches to 2.0 inches of soil,” Lloyd says, noting he’s used infrared thermometers to precisely track temperatures at various soil depths. “But soil temperatures at a depth of 2.5 inches to 3.0 inches are relatively consistent.”

Make sure soils are dry enough and scout fields for issues

Another major planting consideration is making sure fields are sufficiently dried out. “Saturated soils aren’t just sticky and difficult to plant; they also prevent the corn seed from getting the oxygen it needs,” Lloyds says. “Low oxygen creates anaerobic conditions for the corn seed, leading to replants.”

Anaerobic conditions associated with cold, wet soils can also foster seedling diseases like phytophthora and rhizoctonia. When scouting for those threats, Lloyd encourages farmers to carefully dig up a few plants and examine root development. “Roots should be crisp, white and clean when you cut them with a knife,” he says. “If not, you may have some root issues that are difficult to outgrow.”

Farmers, especially those in the Upper Midwest, should also be on the lookout for corkscrewing resulting from imbibitional chilling that can occur when a cold rain or cold snap comes soon after planting.  

Feed corn the nutrition it needs, where it needs it

“A fast, uniform stand is critical. And then keeping that stand growing uniformly until V6 [around the 28-day mark] is important,” Lloyd says. “That’s where fertility comes in.”

Farmers need to make sure corn plants have sufficient fertility by the V2 to V3 stage, before they hit the V6 stage when it’s setting the number of kernels around, according to Lloyd.

Nutrient placement also matters. “More and more farmers are moving to strip tillage and strip fertility, getting the nutrients where the corn roots are located in the first 28 days,” he says. “That’s a win for the environment, a win for the pocketbook and a win for the development of the corn plant.”

“Achieving uniform emergence and then feeding it correctly in that first 28 days goes a long way for corn crops,” Lloyd observes. That goes beyond nitrogen. “Our research and tissue sampling protocol underscored the importance of nitrogen, phosphorous, potassium, sulfur and zinc to plant development.”

Lloyd encourages farmers to do trials on their farms, which can provide critical insights. “Reach out to your local AgriGold agronomist for help getting your corn crop off to a strong start,” he says.