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Soybean continues to be important to many Louisiana farmers, with approximately one million acres dedicated to the crop. The LSU AgCenter uses official variety trials (OVTs) and on-farm demonstrations to provide research that can help growers increase crop efficiency and maximize yield.
In 2024-2025, official variety trials at seven AgCenter research stations included small plot tests for almost 100 varieties. For the core block on-farm variety test program, 21 soybean varieties were entered by seed companies. This test featured 25 demonstrations conducted in 11 different parishes.
“For the maturity group 4.5 to 4.9 core block, the top three yielding varieties had an above average yield for six to seven locations out of eight,” said LSU AgCenter soybean specialist David Moseley. “This indicates the varieties had good yield potential and were stable across locations.”
The on-farm demonstrations were divided by three maturity group sections. Data from these trials were published in the LSU AgCenter 2025 Soybean Variety Yields and Production Practices publication.
“The soybean varieties tend to change year after year, so it’s important to check the new yield book every year to see how the new varieties are performing,” said Moseley.
AgCenter researchers also conducted root-knot nematode resistance screening trials (13 varieties planted in two parishes) where nine varieties yielded between 8-24 bushels higher than the root-knot nematode-susceptible check variety.
In addition, a conventional soybean variety demonstration was conducted in two parishes.
On-farm soil fertility rate and timing trials included:
AgCenter researchers are also looking at a problem called “hidden hunger,” caused by a deficiency in potassium. Healthy looking leaves can fool farmers into believing all is okay.
“In cases of medium potassium deficiency there can be a lack of symptoms, but the plant may still be deficient enough in potassium to lose yield,” said Moseley. “The purpose of this on-farm screening effort is to show people that if your soil test is anywhere near the threshold for deficiency, you need to look at tissue samples, not just an eye test.”
AgCenter researchers are also analyzing randomized potassium (K) application trials to find the most economical rate of potassium application in K-deficient soils, and if in-season applications can capture full yield potential.
It’s part of trials conducted by several universities and funded by a United Soybean Board grant. The national research group is called Science for Success.
“Can you apply in-season and still get the same yield as you would if you applied potassium at planting?” Moseley asked. “Data shows that you can and we’re just trying to verify that data from another state.”
“We’re looking at data for the same thing across the nation, so that gives even more power to the results,” Moseley said.
“For on-farm trials, we have variety trials and fertility trials based on the soil test in different parishes,” Moseley said. “Another one that everyone seems to be excited about is a deer repellent trial in Avoyelles Parish.”
Deer can destroy a soybean field in a couple days. The follow-up tests from 2024, conducted in Avoyelles Parish (in collaboration with other universities), include numerous repellent products — for instance, ones with salts, fatty acids or animal blood — that deer can smell and that taste bad to them.
Planting date trials were another important aspect of soybean research. One study looks at data that points to when plants may flower, as some plants seem to flower earlier than expected.
“We published an article in Agronomy Journal that helps define optimum planting date windows for the northeast, central and southwest regions of Louisiana,” Moseley said. “Planting at these times can help farmers achieve 99% yield potential, depending upon the region and maturity group.”
Another study looked at planting dates and population of soybean plants. In the past, farmers worried if they had less than 120,000 plants per acre there would be a yield decrease, because of too much space between plants, according to Moseley.
“But research year after year shows if you finish with at least 75,000 plants you can still achieve full yield depending on the planting date,” he said.
Moseley and his team of researchers are also looking at different potential harvest aids to complement the commonly used paraquat. “Results from last year help confirm previous LSU AgCenter data that harvest aids did not decrease seed quality or yield when applied at the appropriate growth stage,” Moseley said.
