Biological seed treatment, sulfur, nitrogen, and foliar research

By Dusty Sonnenberg, CCA, Ohio Field Leader, a project of the Ohio Soybean Council and Soybean Check-off

The biological seed treatment market is expanding rapidly. Farmers obviously have questions about the role those biological treatments may play in soybean production and the claims made about the various products. OSU Extension State Small Grains and Soybean Specialist, Dr. Laura Lindsey is conducting research evaluating 9 different biological seed treatments with various active ingredients here in Ohio.

This evaluation is part of a larger research project being conducted by the North Central Soybean Research Program.

“The Ohio Soybean Council funds the Ohio based research through check-off dollars, and the other participating states do the same with their respective check-off money,” Lindsey said. “Overall there are 17 states and over 50 individual field locations involved. The research will continue next year. At the end of the trial, the hope is to have information about biological treatments from 100 locations across the country.”

Dr. Lindsey’s research is being conducted at 6 locations around Ohio and compared 9 different biological seed treatments to a non-treated control. The non-treated control still had fungicide and insecticide seed treatment, but no biological seed treatment.

Some early findings can be documented.

“Initially we have done analysis at our 6 Ohio locations.  We have not seen any of the biological seed treatments statistically improve soybean yield. There has been some gains of 1-3 bushels, but not statistically significant,” Lindsey said. “We are still looking at the data to analyze it in other ways to see if we can find statistically significant differences.”

In another multi-state trial, being led by researchers at Kansas State University, a sulfur and nitrogen study is being conducted. Ohio is participating in this study.

“Nitrogen plays a large role in soybean production. Soybeans need a lot of nitrogen,” Lindsey said. “Applying nitrogen fertilizer to soybeans does not typically do a lot. When nitrogen fertilizers are added to soybeans a yield benefit and economic benefit is not going to be realized at the current cost of nitrogen.”

Fields with a history of soybeans have nitrogen fixation through the relationship with bradyrhizobium japonicum. Bradyrhizobium japonicum is a symbiotic nitrogen fixing bacteria that can cause root nodules to form on soybeans and fix atmospheric nitrogen in a form that plants can use.  

The sulfur study is also a multi-state trial in which sulfur is being soil applied.

“Some locations around the country do see a response to sulfur fertilizer in soybeans. In Ohio we do not see a response to sulfur in soybeans,” Lindsey said. “In other crops, such as alfalfa that has a higher demand for sulfur, farmers may see a response. This is a study we will continue as sulfur may become deficient in the future since we do not see as much atmospheric sulfur deposition. Ohio also did not see a response to the foliar application.”

An additional study is being conducted investigating late timings of fungicide and insecticide applications on soybeans.

“We are looking at foliar fungicide and insecticide applications,” Lindsey said. “We have done studies in the past looking at fungicide and insecticide applications at the R3 growth stage, but not for later applications. This study is looking at both the R3 applications and also the R5 growth stage. From an insecticide standpoint, we are looking at protecting from late season insects such as stink bugs or bean leaf beetles and possible pod feeding. This year’s data is not fully summarized for the study yet. It will likely come out in March.”