With harvest approaching, it appears the yield potential for this year’s corn crop is on the decline, said Chad Lee, extension agronomist with the University of Kentucky College of Agriculture, Food and Environment.

Early indications pointed toward a bin-busting year for Kentucky corn growers, but some of the state’s corn is beginning to drop ears due to a lack of rain during grain fill.  Inadequate rainfall during this crucial growth stage can cause weak development of the shank, which transport nutrients from the stalk to the ear.

“The ears look beautiful, but they are light weight,” Lee said. “The corn is basically running out of water during the critical seed fill stage.”

This is especially true in southern counties in the central and western parts of the state. The U.S. Drought Monitor listed the majority of these counties as in a moderate drought.

“Corn planted from Bowling Green west along the Tennessee state line is in need of rain now,” Lee said. “Rains on Sunday, July 27, provided some relief to northern tier counties, so corn growing from a line between Owensboro to Elizabethtown is in pretty good shape, but they will need additional water in the next five days.”

UKAg meteorologist Tom Priddy said there’s not a widespread rainfall event for the entire state forecasted in the next several days, and it appears the next chance for southern counties to see rain is Thursday.

The National Agricultural Statistics Service rated 34 percent of the Kentucky corn crop in fair to very poor condition for the week ending July 27. However, if no significant rain event occurs, Lee expects more of the crop to decline.