Researchers at the University of California, Davis, have found a way to reduce the amount of nitrogen fertilizers needed to grow cereal crops. The study was published in the journal Plant Biotechnology.
The research was led by Eduardo Blumwald, a distinguished professor of plant sciences, who has found a new pathway for cereals to capture the nitrogen they need to grow.
Nitrogen is crucial to plant growth, and agricultural operations depend on chemical fertilizers to increase productivity. However, an important part of what is applied is lost, leaching into soils and groundwater. Nitrogen pollution can lead to contaminated water resources, increased greenhouse gas emissions and human health issues.
“Nitrogen fertilizers are very, very expensive,” Blumwald said. “Anything you can do to eliminate that cost is important. The problem is money on one side, but there are also the harmful effects of nitrogen on the environment.”
Blumwald’s research centers on increasing nitrogen fixation, which is the conversion of nitrogen gas in the air into ammonium by soil bacteria.
Legumes such as peanuts and soybeans have root nodules that can use nitrogen-fixing bacteria to provide ammonium to the plants. However, cereal plants like rice and wheat rely on fertilizers in the soil, such as nitrate and ammonium, since they don’t have that capability.
“If a plant can produce chemicals that make soil bacteria fix atmospheric nitrogen gas, we could modify the plants to produce more of these chemicals,” Blumwald said. “These chemicals will induce soil bacterial nitrogen fixation and the plants will use the ammonium formed, reducing the amount of fertilizer used.”
Blumwald’s team used chemical screening and genomics to identify compounds in rice plants that enhanced the nitrogen-fixing activity of the bacteria.
They were able to identify the pathways generating the chemicals and used gene editing technology to increase the production of compounds that stimulated the formation of biofilms. Said biofilms contain bacteria that enhance nitrogen conversion. This resulted in an increment of nitrogen-fixing activity of the bacteria, as did the amount of ammonium in the soil for the plants.
“Plants are incredible chemical factories,” he said. “What this could do is provide a sustainable alternative agricultural practice that reduces the use of excessive nitrogen fertilizers.”
Currently, a patent application on the technique has been filed by the University of California and is pending, as the pathway could also be used by other plants.