New research links corn genetics with soil microbes to improve nitrogen use
New research shows that corn bred with genes from its wild relatives can help reduce nitrogen loss from farm fields without reducing crop yield. Scientists found that certain corn genetics can influence soil microbes that cause fertilizer nitrogen to escape into water and the atmosphere.
“We're already showing reductions in nitrification of up to 50% in field and greenhouse trials, which is awesome,” said Angela Kent, the study's senior author and professor in the Department of Natural Resources and Environmental Sciences. “We grow 97.3 million acres of corn in the U.S. every year. If we were able to introduce that trait and reduce nitrification by 50% across that whole acreage, that would have huge impacts.”
Nitrogen is essential for crop growth, but much of the fertilizer applied to fields is lost. Nitrifying bacteria convert nitrogen into nitrate, which can leach into waterways. Denitrifying bacteria can turn nitrate into gases, including nitrous oxide, a powerful greenhouse gas. These losses reduce soil fertility and harm the environment.
Researchers discovered that some ancient corn relatives naturally suppress these harmful microbes. These plants release compounds from their roots that keep nitrogen in a stable form in the soil. Modern corn varieties lost this ability during the Green Revolution, when breeding focused mainly on aboveground traits and heavy fertilizer use.
“During the Green Revolution, we started applying so much nitrogen fertilizer that corn didn't really need to compete with the microbes for nitrogen sources in the soil. There's more than enough nitrogen applied to our field to make nitrifiers, denitrifiers, and the corn happy,” said Alonso Favela, the study’s first author and assistant professor at the University of Arizona.
“But if we want to improve the sustainability of the system and lower the amount of nitrogen fertilizers we're applying to the field, traits that suppress nitrification and denitrification become really important,” said Alonso.
To study this, scientists tested special corn lines that contain small genetic segments from wild corn ancestors. Field and laboratory experiments showed some lines reduced nitrification and denitrification by up to 50 percent. These changes were linked to differences in root chemistry that affected microbial activity in the soil.
Importantly, the researchers tested whether these traits affected yield. When crossed into hybrid corn, the nitrogen-saving traits remained active without reducing grain production. This suggests that the trait could be used in future breeding programs.
Reducing nitrogen loss could lower fertilizer needs, protect water quality, and reduce greenhouse gas emissions. With millions of acres of corn grown each year, this genetic approach could have large environmental and economic benefits.
Scientists believe using plant genetics to shape soil microbes may become a key tool for sustainable agriculture. The findings show that improving how crops interact with soil life can help farmers grow food more efficiently while protecting natural resources.
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