5 Steps to Evaluate Corn and Soybean Replant

09:30AM May 29, 2019
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As rain continues to fall across the Midwest farmers might be wondering if corn stands are strong enough to leave, or if it’s time to replant. Farmers who have planted: here’s when and how to get your boots dirty and scout. 

Wait five days after the event that caused the issue to assess your stand to determine what percent of the crop may recover. University of Missouri Extension provides the following steps to evaluate stands:

1.    Find the cause of the poor stand
2.    Check the density and condition of the stand
3.    Estimate yield potential and gross revenue
4.    Determine replant costs, including seed and equipment
5.    Evaluate cost, returns to see if replant is worth it

If you determine replant is needed it’s important to decide if you’ll need to terminate the original crop or just spot replant. Some of that decision depends on crop type and severity of the damage.

“Once you determine what area or areas you’re going to replant, know that with corn it’s better to take out the previous stand,” says Steve Hoffman, president and managing agronomist for InDepth Agronomy. “Soybeans, one the other hand, have good success if you need to patch in and thicken up stands.”
As you know, soybeans are a bushy plant and can often compensate for low stands. This makes spot-replant more feasible. But it’s important to critically evaluate if replant is even needed—in some cases soybeans can withstand lower stands than you might think.

Don’t forget the damage that could occur from late planting dates, too. Check out the chart below from the University of Missouri to get a general idea of yield expectations, but be sure to check with your local agronomist, too.

Mizzou Chart

Alternatively, corn should not be interseeded with already-growing stands. The smaller plants can’t compete with larger plants, causing them to underperform and steal yield from the larger plants. Experts recommend tillage or herbicides to terminate corn stands.

“Tillage is most effective if the surviving plants are emerged,” says Brent Tharp, Wyffels Hybrids agronomy and product training manager. “you need to work it deep, at least 3 inches at an angle, to tear out the plants.”

If you do choose to use a herbicide to kill the plants check plant-back restrictions before coming back in with seed. In addition, certain trait stacks might limit your herbicide termination options.

calculation chart