Research Highlights

Research Highlights
Achieving soybean seed quality is a combination of nature and nurture

Photo: Ignacio Ciampitti

By Carol Brown

A research team assembled across seven states is collaborating to understand how soybean quality can be improved through best management practices that impact seed composition.

It’s known that soybean seed composition and yield are functions of a combination of genetics, the environment and management practices, but the contribution of each factor is not well-understood. Ignacio Ciampitti, an agronomist at Kansas State University, is leading the team of researchers on a project supported by the United Soybean Board.

“We know that when soybeans have higher yields, 60 to 80 bushels per acre, we see protein levels decline,” Ciampitti said. “While we’re trying to improve yield, we also want to preserve seed quality at the same time.”

Improving or increasing the oil, protein and amino acid composition can increase the value of soybeans.

“We have a deep focus on understanding the quality of sulfur-based amino acids in soybeans,” Ciampitti said. “We are looking at how amino acids are connected to changes in planting date, seed variety, fertilizer and pesticides. If we help soybeans improve nitrogen fixation, can we improve the quality of the seed composition?”

In this third year of the project, the team is conducting a survey to identify farmers’ perceptions of soybean quality. The research team is asking farmers in South Dakota, Kansas, Minnesota, Iowa, Illinois, Indiana and Arkansas to participate in a short survey to help determine factors affecting soybean protein and to help define best management practices for increasing soybean composition quality.

The survey can be accessed here:

Research results

Taking the environmental factors into account, the team found the addition of small amounts of applied nitrogen (less than 50 lbs/acre) improved seed protein and amino acid composition.

Other results from this study include:

  • Diverse crop rotations can improve protein levels.
  • Agricultural practices including no-till, early planting date, lower seed populations, row width, seed treatment, foliar protection and foliar feeding did not appear to affect protein content.
  • Maturity group (MG) selection didn’t influence composition in the northern states but did in the southern states with longer MGs showing a decline in oil and an increase in protein.
Field data collected for soybean studies (2018 growing season) investigating the effect of nitrogen and sulfur application across different US states – yield, protein, and oil distribution (left panels) and amino acid profile in the seed (right panel), all data is expressed in 13 percent moisture basis. Graph: Ignacio Ciampitti

Another strategy many growers practice is treating soybean seeds with a rhizobia inoculant to improve nodulation, nitrogen fixation and yield. However, it was unknown if this practice could improve protein and amino acid quality. To answer this question, the team conducted field trials in four states and across 11 environments. The results showed no effect of seed or additional soil inoculation at V4 or R1 stages on either soybean yield or composition. The team concluded that in soils with previous history of soybean and under non-severe stress conditions, there was no benefit to additional inoculation on soybean yield and seed composition.

A paper on this research was published recently in Scientific Reports Through Nature Research, which can be found here:

Other related publications:

Scientific Reports Through Nature Research: Spatial characterization of soybean yield and quality (amino acids, oil and protein) for United States

Frontiers in Plant Science: Assessing variation in U.S. soybean seed composition (protein and oil)

Published: Apr 16, 2020

The materials on SRIN were funded with checkoff dollars from United Soybean Board and the North Central Soybean Research Program. To find checkoff funded research related to this research highlight or to see other checkoff research projects, please visit the National Soybean Checkoff Research Database.