Soybean Protein 101

 

 

 

 

Have you ever wondered how a soybean plant makes protein? How about ways you can create conditions conducive to boosting protein levels in your fields? Seth Naeve, Ph.D., University of Minnesota associate professor and extension agronomist, explains how it all works.

 

 

A: Protein is partially made of nitrogen. The soybean plant has a symbiotic relationship with bacteria in the soil, which form nodules on the roots of the plant and feed off of sugar produced by the plant. In return for food and housing, the bacteria convert nitrogen from the environment into a form the plant can use. The nitrogen compounds produced in the nodules are then absorbed by the plant, stored in the leaves and later utilized to create protein in the seed. Because of this symbiotic relationship with the bacteria, the nitrogen is basically free for the farmer. That’s one of the good things about soybeans—they have a high amount of protein, which is valuable to end-users. And there’s also value for the farmer because they don’t have to apply nitrogen on their fields to get protein from the crop.

 

 

A: Soil type and climate may be a part of the regional differentiation we see across the U.S.  Unfortunately, those are two things farmers can do little to change. However, there are several things farmers can do to increase protein levels in soybeans. Choosing a high-protein variety and selecting the appropriate maturity group are important – you want to choose plants that will mature under good conditions. Stresses during seed-filling can affect the quality of the soybeans, so minimizing the stresses of insects and disease can have a positive effect on quality. Although farmers cannot change the soil type they have, root health is important for the uptake and metabolism of nitrogen. Building organic matter in the soil will give the plant a bigger reserve of nitrogen to go to when bacteria stop fixing nitrogen at the end of the year.

 

 

A: Protein and oil are the most valuable parts of the soybean, but they’re also the parts that make up the yield of the soybean.