Heavy rains impacting critical window for burndown, fertilization in Arkansas

The steady and significant rainfall experienced by much of Arkansas in late February and early March is tightening a critical window for fertilizing winter wheat in northern Arkansas counties, and delaying herbicide “burndown” operations in others, agricultural agents and other experts with the University of Arkansas System Division of Agriculture said recently.

Robert Goodson, Phillips County agricultural agent, said most of the ground in his county is currently too wet to either apply fertilizer to wheat fields or apply herbicide to other areas as part of the normal field preparation efforts associated with the approach of spring in Arkansas.

“Finding dry ground to put out fertilizer was almost impossible,” Goodson said. “Normally, burndown applications would have been made with ground applicators. But there has been zero acres sprayed with ground rigs and only a few acres sprayed by air. The ‘wet and warm’ has really given the weeds a head start on growing.”

Matthew Davis, Jackson County agricultural agent, reported similar conditions for growers in his area.

“A lot of acres flooded around the Cache River,” Davis said. “There is some damage to beds that were hipped in the fall and some fields will have to be reworked. We need to be burning down—everyone is ready to drop into the field as soon as it is dry.”

Davis said progress in Jackson County isn’t “behind schedule” when compared to an average year, although things are currently running a bit behind 2017—although that’s not necessarily a bad thing.

“I’d rather have the rain now than in May,” he said, when heavy rains and flooding would have a much worse impact on planted acres, as it did in 2017.

Jason Kelley, wheat and feed grains agronomist for the Division of Agriculture, said the rainfall has made fertilizing winter wheat a struggle throughout the state this year.

“Wheat nitrogen fertilization typically is done beginning in late January through March, with the starting and ending dates driven by crop growth stage,” Kelley said. “So north to south in the state, we typically see some variation in timings.

Kelley said growers typically “split-apply” nitrogen to help diffuse environmental risks, applying nitrogen when crops need it.

“We generally apply the first application at ‘green up’ which would normally be in early February, and then apply the second application three to four weeks later,” he said. “When the initial application of nitrogen is delayed past the ‘jointing’ stage, yields decline. The jointing stage signifies that the plant is going into a rapid reproductive growth stage and has a high demand for nitrogen.”

Kelley said the lack of nitrogen applications in late February has caused some concern among both growers and agronomists. Many growers are hoping to apply the fertilizer before the next wave of rain hits.

“Overall, many wheat fields are yellow, likely due to a lack of nitrogen, but saturated ground and water logged conditions may be a bigger factor for yellow wheat this week,” he said. “Impact on yield is yet to be seen, but growth stages this year are behind where we were last year.”

To learn about Arkansas row crops, contact your local Cooperative Extension Service agent or visit www.uaex.edu.