Research HighlightsMaking the most of management practices to improve soybean seed protein
By Carol Brown
Protein is the key ingredient in soybean meal for quality livestock and poultry feed in the United States and beyond. But in the last few decades, protein concentration levels in soybeans have declined, even while yield has increased. To keep soybean meal as a viable product for domestic and export markets for American farmers, protein levels need to improve to the amounts they were before or better.
How farmers manage their soybean fields could affect the amount of protein in the harvested seed. Researchers are trying to improve protein concentrations by focusing on how the soybean plant uses those management actions that increase protein levels.
Anna Locke is a research plant physiologist with the United States Department of Agriculture (USDA) at North Carolina State University. She is leading a team of researchers in a two-fold project: Exploring environmental factors that impact soybean seed protein levels and determining the underlying mechanisms within the plant that are affected by those environmental factors.
“If we know more about how the environmental impacts work inside the plant, we might be able to discover different ways to either improve the breeding process to increase protein, or maybe find a new gene — we can use biotechnology to improve seed protein concentration,” said Locke.
With funding support from the United Soybean Board, the research project focuses on how cultural practices and farmer management decisions including fertilization strategies, tillage, irrigation, and seed planting density, change how the crop behaves. The team is testing those specific management factors with a variety of soybean cultivars to see how they impact seed protein.
“We know from lots of other research that seed protein concentration depends on the variety of soybean and that the environment can alter the protein concentration,” Lock said. “Obviously, there are a lot of things regarding the environment that none of us can do anything about, but there are many things that farmers can control in some way.”
The research is being conducted at university- and USDA-owned research stations in North and South Carolina. The team is in the middle of their second year of research, but the first year of study did not cooperate as well as Locke would have liked.
“The fall of 2018 was really damp. We got some results, but they weren’t overly reliable,” she said. “We’re in the process of analyzing the data from 2019’s harvest and I’m optimistic we’ll have useful recommendations that farmers can use.”
Nitrogen movement in the soybean is one of the components the researchers are studying. Much of the seed protein concentration depends on the movement of nitrogen into and around the plant, said Locke. Some soybean varieties are more successful than others with nitrogen fixation, which is the process of capturing nitrogen from the atmosphere, therefore reducing the need for applied fertilizer.
“We’re evaluating how much nitrogen, in different varieties and different management treatments, is coming from the biological nitrogen fixation process compared to an uptake of nitrogen from fertilizer,” Locke said. “We want to see if we can link this to any of the differences in seed protein.”
The team is set to begin work on the upcoming growing season and Locke hopes to add another component to the study this year.
“We want to follow up and refine the crop management recommendations that can increase seed protein, and I want to add an economic analysis,” Locke said. “It costs farmers money to apply fertilizer to get that protein increase, which also affects their bottom line. Will farmers benefit from this expense or will it only affect the value of the soybean down the product pipeline?”
Locke and her research team will continue to study these components, which will hopefully help the farmer’s input costs as well as profit in the long run.
Published: May 6, 2020
This project was funded by the soybean checkoff. To find research related to this research highlight or to see other checkoff research projects, please visit the National Soybean Checkoff Research Database.