Nitrogen 101 – Biological nitrogen fixation for plant growth and health

Feb 3, 2023 | How it works

It moves through living and nonliving things, permeating the atmosphere, water, soil, plants, animals and microscopic beings. It is odorless, colorless and tasteless. Like water, it has a repeating cycle upon which life depends. What is it?

Nitrogen, of course! OK, maybe that wasn’t obvious. After all, it’s not every day that most folks ponder the importance of various chemical elements. However, at TerraMax Ag, that’s a common occurrence for scientist and CEO Doug Kremer and director of research Molly Tillman.


The nitrogen cycle: Nature’s process

Nitrogen makes up about 78% of our atmosphere. It is a crucial element in molecular building blocks that make critical things like proteins and DNA. When organisms and their waste decompose, nitrogen is released back into the atmosphere, completing the nitrogen cycle.

Nitrogen is critical to Kremer and Tillman’s groundbreaking work at TerraMax, an innovative ag-tech company that makes microbial inoculants for farmers that promote healthier plants and higher yields at the soil level.


How roots interact with microbes

Plants require nitrogen to make proteins and enzymes just like we do, but they can’t just pull it from the air the way our lungs take in oxygen. Instead, plants rely on microbes in the soil to access nitrogen. This process is called nitrogen fixation.

“Biological nitrogen fixation has been around as a part of ecosystems and plant growth,” says Kremer. “I’m not sure you can put a date on it, but let’s call it eons.”

Even though there’s a ton of nitrogen in the atmosphere, it’s not available as is to plants. It all depends on the soil.

“Nitrogen is typically the primary limiting nutrient to plant performance and crop productivity,” says Tillman, meaning that even if a farmer’s corn plants have all the light and water they need, if the plant can’t get enough nitrogen, the entire crop will suffer.

Soybeans, lentils and certain plants called legumes have nodules on their roots that form a mutually beneficial relationship with nitrogen-fixing microbes. “Leguminous plants evolved the specific relationship with different microbes,” says Kremer. “The real challenge in biological nitrogen fixation is non-leguminous plants. They didn’t evolve with the ability to interact with microbes.”

“More research on the soil microbiome is coming out these days that point to bacteria that live in the soil that can fix nitrogen,” Kremer explains. “The question is, how do you harness those things for nitrogen fixation in non-leguminous plants? And how can we get more nitrogen into the plant by way of nitrogen fixation?”


Too much of a good thing?

A common solution has been to apply nitrogen-rich fertilizer to crops. But there are consequences. When it rains, some of the nitrogen-rich fertilizer washes away. Nutrient overload in waterways causes algae to bloom prolifically, absorbing oxygen in the water and blocking sunlight from reaching creatures and plants under the surface.

“While everyone thinks nitrogen costs a lot today, the production cost is only a portion of the societal cost of applying nitrogen to plants,” Kremer explains. “Other issues have been tied to using applied nitrogen, like pH changes in the soil. It’s only been about the past three decades that we agricultural scientists have given more attention to the nonfinancial costs of using that kind of fertility.”


Nature’s process, perfected by science

Fortunately, there’s a better way to help non-leguminous crops like corn, wheat, and grasses access the nitrogen they need, and it is more cost-effective and sustainable than applying fertilizer. TerraMax products contain select strains of microbes that can effectively pull nitrogen from the air and fix it in the soil around a plant’s root system. “What we’re doing is taking nitrogen from the air and, through our microbes, making it into a form that is available for plants,” says Tillman. “We’re utilizing a natural process to take advantage of what’s already there.”

TerraMax makes nitrogen-fixing products for a wide variety of crops. They focus primarily on traditional soybean inoculants, but also craft solutions for corn, wheat and related grasses. While Tillman and Kremer have rigorous research and data to support their products, the true measure of success is in the field.

TerraMax has documented higher crop yield from corn and wheat to rice and small grains. When plants effectively fix and use nitrogen, they are healthier, which is evidenced by increased protein content in wheat and triticale.

“We are always targeting yield increases,” Tillman emphasizes. “That is the driving force behind what becomes a product. It always comes back to yield increase and return on investment for the farmer.”