Hail-bearing thunderstorms sweeping across the Hoosier state this month beat up young crops. And while some corn and soybean fields look down for the count, farmers should not let their emotions cloud their management decisions, said Purdue University agronomists.

Corn and soybean plants can regrow lost leaves and tissue with minimal yield reduction, said Shawn Conley, Purdue soybean specialist. Unless stems are snapped off or more serious damage has occurred, growers should not need to replant, he said.

“A soybean plant can withstand a significant amount of leaf defoliation caused by hail damage early in the growing season,” Conley said. “Our research shows that up to about the R1 stage of crop growth - or when that soybean plant starts flowering - you could lose almost every single leaf on a plant and still have 100 percent yield potential.

“When we get damage to the nodes and stems breaking off, however, we tend to see some yield loss. For example, if you walk into a soybean field at the V2 growth stage and 20 percent of the nodes are removed, you’re looking at only 3 percent yield loss. If 40 percent of the nodes are cut off, that’s 7 percent yield loss.”

At the V2 - vegetative two - stage, soybean plants have four nodes and two three-leaf clusters, or trifoliates. During the later reproductive one (R1) stage, the plant has multiple trifoliates and is starting to bloom.

Were the 2006 crop further along in development, hail damage could be worse, Conley said. Many corn and soybean crops are smaller than normal because farmers were unable to plant on time this spring. Again, weather was the main culprit.

It is natural for farmers to feel frustration and anger when crops are damaged by weather, said Bob Nielsen, Purdue corn specialist. Producers need to control their urge to do something, he said.

“Be patient. The crop could recover,” Nielsen said. “Most of us, because we’re human, overestimate the field damage. Usually the damage ends up being less serious than what it appears to be.”

Even if crop damage is significant, it might be too late for farmers to perform a quick fix, Conley and Nielsen said.

“We’re getting so late in the season that we’re pretty much stuck with the yield potential we have out in the field,” Conley said. “A lot of that depends on where you are located in Indiana. The farther south you are, and in those areas where you can double crop beans following wheat harvest, you can replant and still have decent yield potential.

“As you move into the northern counties, the yield penalty you’d experience by tearing up those fields and replanting is much greater than the loss you likely could have from the hail damage itself.”

Conley recommends farmers contact their crop insurance representative about the feasibility of replanting.

As the season progresses, hail-damaged crops could be susceptible to weeds that grow through damaged plants, Conley said. In those situations farmers might consider an additional herbicide treatment. Injured crops are not at higher risk of disease, unless plant tissue remains exposed, he said.

“Continue to scout those fields and look for problems,” Conley said. “What we’re most likely to see are delays in crop maturity at the end of the season in those hail-damaged fields.”

For additional soybean management tips and information, log onto the Cool Bean website, located at www.coolbean.info

Corn growers with damaged fields can read Nielsen’s publication, “Hail Damage in Corn: Moving Beyond Grief to Damage Assessment.” The publication can be downloaded at www.agry.purdue.edu/ext/corn/news/articles.01/Hail_Damage-0606.html

This farm news was published in the July 5, 2006 issue of Farm World, serving Indiana, Ohio, Illinois, Kentucky, Michigan and Tennessee.