University of Illinois Outlines Planting Dates for Highest Corn and Soybean Yields

While Illinois crop producers are encouraged to plant in mid-April, data shows waiting for dry conditions will not dramatically reduce yields.
While Illinois crop producers are encouraged to plant in mid-April, data shows waiting for dry conditions will not dramatically reduce yields.

Data released from the University of Illinois on April 26 showed that 42 percent of corn and two percent of soybean crops have been planted as of April 24.

While the optimal times to plant for both crops appear to fall in mid-April, Illinois Crop Scientist Emerson Nafziger claims that farmers who are waiting for drier field conditions may not see a large yield penalty.

“We’ve run 35 corn planting-date trials in central and northern Illinois over the past nine years, with four planting dates at each site beginning in early April and going through late May or early June,” Nafziger stated.

After April, Nafziger predicts corn yield losses of about four percent by May 10. The losses increase to eight percent by May 20, and 14 percent by May 30.

For soybeans, the yield loss is predicted to be seven percent by May 10, about 10 percent by May 20, and approximately 16 percent by May 30.

“While letting both crops planted on time is beneficial, we shouldn’t lose sight of the fact that yield losses for delays into and even past mid-May are not so large that we need to give up hopes for a good crop if we aren’t done planting by the end of April,” Nafziger continued.

Neither soybeans nor corn tends to suffer dramatically from planting in early May. However, Nafziger still encourages the planting of corn before soybeans to give the soil an opportunity to warm up.

More details on Nafziger and the University of Illinois’ findings can be seen on http://bulletin.ipm.illinois.edu/?p=3564.