Nitrogen fertilizer plays a vital role in agriculture by allowing farmers to produce more food on limited acres. However, given the high cost and environmental impact, some farmers are looking more closely at either reducing or optimizing this major crop input. They are not alone.

The future of nitrogen fertilizer use on the farm may rely on an industry directive, scientific research, seed company development and farmer acceptance.

A 2022 report by the International Fertilizer Association and Systemiq, “Reducing Emissions from Fertilizer Use,” states that emissions from mineral fertilizer production and mineral fertilizer account for 6% of all greenhouse gas emissions from the food sector. Subsequently, the IFA established a target to reduce GHG emissions from nitrogen fertilizer use by 70% by 2050.

AgTech Next convened a panel of scientists and fertilizer industry leaders to discuss attainability of this goal.

Nitrogen research center

Scientists at the Donald Danforth Plant Science Center are developing technologies that will decrease the use of nitrogen fertilizer by 12% without the loss of crop productivity.

In 2021, the St. Louis-based research facility established a new Subterranean Influences on Nitrogen and Carbon (SINC) Center of Excellence to address this global challenge. Rebecca Bart, director of the SINC Center, is digging deeper into microbes that can turn nitrogen from the air into a form usable by plants in the ground.

“There are over 100 products out there already available to farmers as soil amendments or seed treatments,” Bart explained. “Most of them really do work, but all too often, when they're used by farmers, they actually don't work.”

She said it is the complexity of agricultural soils and the difficulty of manipulating the microbiome that causes those failures.

“Through the SINC Center, not only are we identifying novel classes of microbes, but we are figuring out what that secret sauce is that's going to allow not only our microbes to work really well, but all of those other products out there as well,” Bart said.

SINC scientists are tracking the flow of nitrogen and carbon across plant roots, discovering novel beneficial microbes, and understanding the genetic mechanisms that influence these interactions. For a beneficial microbe to work, Bart explained, it must “play well with its plant host,” and there is a lot of room for improvement in this area. Still, she said some of the flaw is on the plant itself.

Digging deeper into genetics

“Over at least the last seven years, we've been breeding our plants in the context of excessive nitrogen and fertilizer, giving them everything they wanted,” Bart said. “So, have [plants] been incentivized to do things efficiently? No, of course not. So, there's a ton of room for improvement on the plant side, if we're smart enough to find it.”

Ryan Bond, senior director, Global Proprietary Business Development and Innovation for Nutrien Ag Solutions, agrees.

“On the biological piece, you can design the microbe to fix more nitrogen,” he explained. “I have a lot of movement on the synthetic biology piece, but where's the piece on the genetics?” It may be at the University of Nebraska-Lincoln.

“Creating corn that fixes nitrogen would be a holy grail of helping us get toward these emission targets,” said Daniel Schachtman, director of the UNL Center for Biotechnology.

Schachtman, who conducts work regarding microbiomes, is partnering with a UNL geneticist. “We're trying to combine these two areas of research to identify the right microbes that fit with the right plants.” But it will take time and collaboration to develop commercially available hybrids.

Meanwhile, natural nitrogen-fixing corn hybrids do exist. In 2018, researchers with the University of Wisconsin-Madison, University of California Davis and Mars Inc. shared findings of such corn hybrids in Mexico.

The corn varieties stand more than 16 feet tall and develop up to 10 sets of thick aerial roots that never reach the ground, according to the University of Wisconsin news release.

Under the right conditions, these roots secrete large amounts of sugar-rich gel, providing the energy and oxygen-free conditions needed for nitrogen-fixing bacteria to thrive. At the time, University of Wisconsin-Madison researcher Jean-Michele Arne said development of this hybrid for commercialization was 10 years away.

Farmers need to buy in

No matter if the nitrogen solution comes from new microbial action or corn genetics, it will take farmers embracing the technologies. But there is a disconnect from the scientist to the fertilizer industry to the farmer.

“Why do we have a problem with adoption [of technology]?” Bart asked. “Is it the market? Is it the cost? Is it with carbon credits that we don’t have the ability to actually accurately measure the effects of our technologies? Once those are clearly identified, then scientists can figure out how to overcome the challenges and invent around those problems.”

Reduce nitrogen use up and down supply chain

According to the International Fertilizer Association, much of the 70% reduction in GHG emissions by 2050 can be achieved by focusing efforts within the sector’s current value chains and business models, including the following strategies:

Improving nitrogen-use efficiency. Using fertilizer more efficiently would ensure that a higher proportion of nutrients are taken up by the crops and less escapes as GHG and other forms of pollution. The industry’s 4R framework — applying the right nutrient source, at the right rate and time and in the right place — are examples of the sorts of actions farmers can take to achieve these improvements.

Developing and applying existing technologies and producing new ones. Additional products such as urease and nitrification inhibitors and controlled-release fertilizers have the potential to further help reduce emissions. More research and product development are needed to make these technologies more affordable, and to better understand how they work together and their wider environment impacts.

Promoting wider changes in the agri-food system. This includes farmers growing more legumes (e.g., soybeans) that need less fertilizer, and populations reducing their animal product consumption in countries where it makes sense to do so.