Arkansas soybean planting date, breeding studies seek to optimize production
Aug. 10, 2026
By John Lovett
University of Arkansas Division of Agriculture
Fast Facts
- Planting-date research helps farmers decide whether to plant rice or soybeans first
- Early maturity groups did better when planted later
- Soybean Breeding Program makes advancements in root-knot nematode resistance
(873 words)
Download PHOTOS of Justin Chlapecka and Caio Vieira
FAYETTEVILLE, Ark. — Soybean planting decisions in Arkansas can hinge on everything from soggy spring weather to shifts in the global rice market.
When spring weather limits chances for fieldwork, producers must decide which crop gets planted first: rice or soybeans.
For researchers with the Arkansas Agricultural Experiment Station, the University of Arkansas Division of Agriculture's research arm, understanding how planting timing and maturity group affect soybean yield could help answer a practical question many farmers face every spring.
“We know farmers are looking at the economics and feasibility of all the factors,” said Justin Chlapecka, an assistant professor of agronomy in the department of crop, soil and environmental sciences. “They might have just a two-day window before it rains again in April and might not be able to get in the field for another three weeks. So they’re asking, ‘Should I plant beans, or should I plant rice?’”
At the Northeast Rice Research and Extension Center in Harrisburg, Chlapecka has been researching how planting date and maturity group combine to affect soybean management and yield potential.
Over the past two growing seasons, his work examined six planting dates from late March through early June using soybean maturity groups ranging from Group 3 to Group 5.
“I know we’ve done a ton of planting-date trials, and it may seem like beating a dead horse, but we’re looking at it in tandem with the rice planting-date trials,” Chlapecka said during the center’s Rice and Soybean Field Day on July 30.
The answer, Chlapecka explained, depends as much on economics as agronomics. Early planting generally creates opportunities for higher yield potential. Still, those advantages must be weighed against management realities, harvest timing, crop quality considerations and weather risk, he said.
Soybean response varied by maturity group
Spring weather during the research period made that question even more relevant. Within a week of the second planting date, on April 1, 2025, Chlapecka’s research plots received about 13 inches of rain, creating conditions similar to those many Arkansas producers face in rice-soybean rotations. An 8-inch rainfall this past June also caused issues, he said. The flooding damaged some plots but also highlighted how soybean varieties respond under the same stress conditions farmers commonly face.
“We knew that it was going to fail, but it’s a planting-date study. So, we go ahead and do what we can do,” he said.
While early planting will lead to an earlier harvest date, Chlapecka said early-maturity Group 3 soybean plants performed better when planted later in the season. The later-maturing Group 4 and Group 5 varieties generally demonstrated stronger yield potential when planted earlier.
The findings suggest soybean maturity selection could give producers more flexibility when deciding whether to use limited planting windows for rice or soybeans.
Greater flexibility in soybean planting dates could improve harvest efficiency by reducing pressure to harvest both crops within the same narrow window, he said.
“Especially with hybrid rice, we can maybe push that later and still get the potential we could out of harvesting some of these early beans if the goal is to get beans out of the field first,” he said.
Breeding soybeans for flood and drought tolerance
Even with improved production strategies, weather extremes remain a challenge for soybean farmers.
Through his work in the Division of Agriculture’s Soybean Breeding Program, Caio Vieira, an assistant professor in the department of crop, soil and environmental sciences, is working to develop soybean varieties that can better tolerate the stresses Arkansas producers routinely face.
“The reason we exist is to improve soybean genetics available to Arkansas growers,” Vieira said. “A lot of the work we do is funded through the soybean checkoff money, and that is important because we can target some of the local problems.”
The Soybean Breeding Program produces roughly 200 crosses each year, generating about 20,000 new genetic combinations that are evaluated across Arkansas and the Mid-South.
Using managed flooding experiments, Vieira’s team evaluates soybean responses at both vegetative and reproductive growth stages, searching for genetics that can withstand short-term flooding and rain-dependent conditions without sacrificing yield.
Standing in front of a soybean field divided between irrigated and rain-fed management, Vieira explained how researchers are using new technologies to identify traits associated with strong yield performance.
“Both of these trials have the exact same genetics, but one is irrigated and the other rain-fed,” Vieira said. “We’re using a multitude of technologies, including drones, genomics, and many other things to try to identify what is sustaining yield under rain-fed conditions.”
Building nematode resistance
The Soybean Breeding Program has also sought to develop varieties with resistance to plant-parasitic nematodes.
“Root-knot nematode is probably the No. 1 yield-limiting disease that we have here in Arkansas and other Mid-South locations,” Vieira said.
Supported by the Arkansas Soybean Promotion Board, the U.S. Department of Agriculture and the Mid-South Soybean Board, the program has made significant progress in identifying root-knot nematode resistance, Vieira said.
“Just a few years ago, we had less than 5 percent resistance to root-knot nematode in our germplasm, and now we have 35 to 40 percent of the materials coming with resistance,” he said. “We’re really trying to shift what we have in terms of resistance, and that translates to better yield under nematode pressure.”
To learn more about ag and food research in Arkansas, visit aaes.uada.edu. Follow the Arkansas Agricultural Experiment Station on LinkedIn and sign up for our monthly newsletter, the Arkansas Agricultural Research Report. To learn more about the Division of Agriculture, visit uada.edu. To learn about extension programs in Arkansas, contact your local Cooperative Extension Service agent or visit uaex.uada.edu.
About the Division of Agriculture
The University of Arkansas Division of Agriculture’s mission is to strengthen agriculture, communities, and families by connecting trusted research to the adoption of best practices. Through the Agricultural Experiment Station and the Cooperative Extension Service, the Division of Agriculture conducts research and extension work within the nation’s historic land grant education system.
The Division of Agriculture is one of 22 entities within the University of Arkansas System. It has offices in all 75 counties in Arkansas and faculty on three system campuses.
Pursuant to 7 CFR § 15.3, the University of Arkansas Division of Agriculture offers all its Extension and Research programs and services (including employment) without regard to race, color, sex, national origin, religion, age, disability, marital or veteran status, genetic information, sexual preference, pregnancy or any other legally protected status, and is an equal opportunity institution.
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Media Contact:
John Lovett
U of A Division of Agriculture
Arkansas Agricultural Experiment Station
(479) 763-5929
jlovett@uada.edu