With corn prices at record highs, many farmers are considering replanting flood-damaged fields, although years of data advise caution with such a decision. Recent yield simulations run by Iowa State University's Department of Agronomy show that while the economics may work out in a perfect situation, replanting carries with it some major risks.

“Corn planted this late has an early frost damage risk of around 40 percent in the southern part of the state (Iowa) and as high as 66 percent in the northern areas,” says Roger Elmore, Iowa State Extension corn agronomist. “An early frost could mean the difference between 130 bushels an acre and 24.”

While this study and statement reflect Iowa's frost potential and yield declines, similar patterns can be applied to other parts of the country.

For Iowa, simulations of yield potential for corn acres planted by July 1 show early season hybrids will be the only reasonable option for anyone who finds it economical, and worth the frost risk, to replant. But planting the early season hybrids creates an additional risk since these varieties are less suited to Iowa’s environmental stresses and disease.

If the weather is perfectly suited to growing corn from now until harvest and land is replanted by July 1, it may be possible to reach yields of 100 to 130 bushels an acre. But grain moisture content could be as high as 37 percent which means yet another additional cost to dry down the harvest, notes Elmore.

For the complete details of the simulation, click here.

Given the high prices of other commodities besides corn, farmers should also consider the benefits of planting soybeans, grain sorghum, various spring and summer annual forage crops, or even leaving the land fallow, he adds.

“The yield potential for corn drops off precipitously every day planting is delayed,” says Elmore. “Our research shows a daily drop off in yield of 2.5 percent. And if you can’t plant before July 1, corn really isn’t an option.”

Source: Iowa State University