North Carolina State University is continuing its research this year on both foliar feeding of soybeans and  fungicidal seed treatments to determine if these practices will help North Carolina farmers increase their current average statewide yield of 35 bushels per acre.

At this year’s virtual Blackland Farm Managers Tour, Rachel Vann, North Carolina State University Extension soybean specialist, discussed a national collaborative research project examining the value of foliar feeding soybeans, especially in the reproductive growth stages where farmers are already making fungicide and insecticide applications.

The research began in 2019 and continues this year in 20 sites across the United States and in three sites across North Carolina. The research is examining the value of foliar feeding soybeans at the R3 or beginning pod growth stage. In essence, Vann says the research showed in 2019 that there was no impact on soybean yields in 95 percent of the sites when a foliar fertilizer was applied at R3.

“I’ll often get the comment that you didn’t look at these products in high enough yield environments. One of the beauties of doing this research on a national scale is we are very quickly able to capture a wide range of yield environments. In 2019 we had sites with average yield of 27 bushels per acre all the way to sites with average yields all the way up to 82 bushels per acre and greater,” Vann said.

In all of the yield environments, Vann said there was no yield advantage in 95 percent of the sites of a foliar fertilizer applied at R3. The research continues this year to see if the same results will be achieved as last year.

Meanwhile, as North Carolina soybean farmers seek to plant soybeans earlier, they often question if a fungicidal seed treatment is a necessary production tool. Vann and her team are evaluating data from the past five years looking at the benefit of fungicidal seed treatments across 15 different environments in North Carolina.

“We concluded that fungicidal seed treatments did not impact yield. However, these trials were planted from the middle of May to early July. What if we’re planting soybeans in early April? Do weed need a fungicidal seed treatment then?” Vann asked.

North Carolina State began research in 2019 looking at various fungicidal seed treatments across planting dates from early April into late June and across three different soybean maturity groups. At the Beaufort County site in 2019 — when planting dates and maturity groups were averaged together — the fungicidal seed treatment protected the soybean stand an average of 15,000 plants per acre.

In 2020, with the wet and cool spring, Vann said she was anticipating a large impact of the fungicidal seed treatments on soybean stands. However, in the Beaufort County sites and other sites across the state, there was minimal impact on soybean stand this year.

“One of the reasons may be this site has low seedling disease pressure. Another reason is we have a new research planter. In the past, we’ve been using cone drills which dribbled the seed out. But now we have a new vacuum planter that more precisely places the seed and also has more uniform depth,” Vann said.

In last year’s research, two harvested sites showed yield protection of six to seen bushels per acre from the use of fungicidal seed treatment. At one site, there was no impact on yield.

“Last year we saw more of an impact on protecting soybean yield when these fungicidal seed treatments were used at earlier planting dates: Nine bushels per acre at the very earliest late March planting date, six bushels per acre at that middle of April planting date and about a two bushel per acre yield protection at that mid-May planting date,” Vann said.