With rainfall scarce and temperatures reaching for triple digits in late June, the Mid-South corn crop can go one of two ways. It can maintain a good yield potential established in early May, especially if it’s irrigated. Or it can head downhill in a hurry, if it’s dryland corn and rain continues to hold off.

“Compared to the last two years, our corn crop was looking excellent, up until this last week or two of heat,” said Jason Kelley, wheat and feed grains specialist at the University of Arkansas. “We got a lot of early corn in this year, and did not have to replant much like we did the last two years. A lot of that March corn came up to good stands with vigorous growth and good root systems.

“The demand for water has just been incredible. We’re trying to water soybeans up in some instances, get rice flooded up and watering cotton. Some producers may have all those crops, and it’s pretty tough to keep ahead of things.”

Kelley says corn uses a third of an inch of water a day. “If you make a circle every three or four days and put out an inch, you’re just barely keeping up. If you shut the system off for a day, you’re going to get further and further behind. We’re in a very critical time. A lot of the corn has pollinated, but we can still have a lot of kernel abortion if we don’t keep up on the water.”

Between 80 percent and 85 percent of the Arkansas corn crop is irrigated, according to Kelley. Kelley says dryland corn “is starting to go downhill very quickly.

“As a general rule, the irrigated corn is very good,” said Mississippi Extension grain crop specialist Erick Larson. “The crop through May was in a lot better condition than it’s been the last couple of years due to dry conditions. Growers were encouraged by the root development and better plant development in the early stages.

“The exception to that would be the north and northeast parts of the state, which was wet during May. Those areas are going to be quite dependent on rainfall over the next month.”

The irrigated crop “has continued to look good, for the most part,” Larson said. “I expect that the yield potential will be quite high relative to the producers’ ability to irrigate and keep water supplied to the crop. The heat will reduce the yield potential somewhat, but it won’t be a large determining factor relative to yields.”

Meanwhile the dryland crop is starting to falter under the heat. “A few dryland areas have received above average rainfall over the last two weeks, which will help. But by and large, most of the state has been extremely dry.”

If you’re a west Tennessee corn producer, and you had good moisture levels going into the recent run of hot, dry weather, your crop is probably holding up well in late June, according to Angela Thompson McClure, the state’s corn and soybean specialist.

“The early corn is pollinating or has pollinated. We do need some rain to help fill the ears.”

Thompson said some growers have inquired about fungicide on corn, a practice which has shown mixed results. “Fungicide prices have gone down a little and that helped it pencil out. But you have to make so much more corn to pay for the cost of the aerial applicator. But growers who contracted corn at a good price are looking to bump yields just a little, if they can get a reasonably-priced fungicide.”

According to John Kruse, corn and cotton specialist at the LSU AgCenter, “if growers aren’t irrigating their corn, there are going to be dramatic differences in yield this year. We came into February with plenty of moisture. There was a little bit of concern about timely burndown, but then it just got drier and drier. Now we’re well into pollination and beyond.”

April and May “have been quite dry,” Kruse said. “Dryland corn is curled up every day, and has a pale cast to it from inadequate nitrogen. For irrigated corn, growers have done an overall good job of keeping up with the water requirements. Irrigated corn is going to be in pretty good shape, but his dry weather did affect pollination to some degree, so I just don’t know how that’s going to play out in yield at the end of the year.”

According to USDA’s Crop Progress report for the week ending June 20, about 75 percent of the nation’s corn crop is listed in good to excellent condition, with only 5 percent in poor condition. That’s on par with conditions this time last year.

e-mail: erobinson@farmpress.com