Fixation research might help farmers abandon nitrogen fertilizers

University of Missouri researchers are developing a method to reduce farmers' dependence on nitrogen fertilizers, the university said on Friday.

Many farmers use nitrogen fertilizers to improve crop yields and maintain crop quantities. Around the world, growers used over 100 million tons of nitrogen in 2011 alone. Also in 2011, the U.S. imported and produced over $37 billion worth of nitrogen.

The new method also might reduce costs for farmers, eliminate runoff into water supplies, create stronger plants and grow more food for an increasing worldwide population.

“Biological nitrogen fixation — in which bacteria fix atmospheric nitrogen and convert it to ammonium — provides a free way for plants to assimilate and metabolize nitrogen,” Fernanda Amaral, an MU postdoctoral fellow and researcher in the Bond Life Sciences Center, said. “Farmers have long known that legumes like soybeans fix nitrogen because of the symbiosis between the plant and bacteria in the soil. Normally, plants develop nodules on their roots. However, since grass plants that produce food, such as corn, rice and sugarcane, don’t form these specialized structures, that relationship has been trickier to explore in these plants. Therefore, we needed a plant model to help us study how nitrogen fixation naturally happens.

“We wanted to identify the genes responsible for the interaction between plant and bacteria, and mainly the ones involved with the nitrogen uptake,” Amaral said. “By identifying the bacteria that allows plants to take in nitrogen, we may have found a more efficient and eco-friendly way to farm. Setaria viridis grass can serve as a simple model for research and can substitute for grass relatives such as corn and rice. Further studies may explore a similar relationship in those food crops and could lead to a plant-friendly way to promote more sustainable agriculture.”