As many of the state's rivers continue to rise, the state's corn and wheat producers are playing a waiting game with Mother Nature before they can assess the damage, said Jim Herbek, grain crops specialist with the University of Kentucky College of Agriculture.
According to the National Weather Service, the Green River at Paradise is expected to crest today, May 6, at 396.9 feet. This is well above the major flood stage of 390. Moderate flooding is expected on the Ohio River at Cairo when it crests today at 49 feet, 9 feet above flood stage. The Mississippi River at New Madrid is expected to crest at 37 feet May 7, which is 3 feet above the flood stage. The Ohio River at Owensboro is expected to crest near the flood stage of 40 feet May 8.
According to the latest crop progress report by the U. S. Department of Agriculture, 83 percent of the state's corn crop was planted and 59 percent has emerged. The crop was well ahead of the state's 5-year average of 59 percent planted and 30 percent emerged because of the dry weather during the last week of March and first two weeks of April.
Much of the state's corn is still relatively small and could easily be completely submerged by 3 to 4 inches of flood water. Most of the wheat is tall enough that it may not be affected as much by flood waters.
Herbek said crops can survive up to 72 hours under water without sufficient damage if temperatures are less than 70 degrees. Warmer temperatures will decrease the amount of time that young corn plants can survive under water.
"Temperatures warmer than 75 to 80 degrees are probably the worst-case scenario," he said.
Depending on a producer's location to a flooded river or tributary and the amount of rain the area received, anywhere from 35 to nearly 70 percent of crops in Western Kentucky are currently under water according to agents with the University of Kentucky Cooperative Extension Service. On average, agents are expecting losses of around 10 to 20 percent to the corn crop. However, in some areas, like Ohio County which has the majority of its corn under water, it's estimated that as much as 60 to 70 percent of the crop could be lost and need replanting.
Producers will not be able to assess any damage to their fields until a few days after the flood waters have subsided. The plants will likely be yellow, but if the growing point is white and turgid, the plant is alive.
For those needing to replant, the optimum planting date is quickly approaching for much of the state. In far western Kentucky, the date is between May 5 and May 10, and for those farther east, it's May 10 to May 15. However, there's still hope for good yields in crops planted after these dates. Much of the crops success will depend on the weather throughout the growing season.
"Last year, much of our crop was planted late, but with the cool summer we had, yields turned out better than anticipated," said Herbek.
More information on flood damage to crops and replanting is available in the UK publication AGR-193: Evaluating Flood Damage in Corn and AGR-195: Replanting Options for Corn. Both are available online at http://www.ca.uky.edu/agc/pubs/agr/agr193/agr193.pdf and http://www.ca.uky.edu/agc/pubs/agr/agr195/agr195.pdf.