By Jamie Martin
Scientists have discovered that corn bred with genes from its wild ancestors can reduce nitrogen loss from fields without affecting crop yields. The research highlights how plant genetics can influence soil microbes that control how fertilizer nitrogen behaves in the soil.
“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.”
In modern agriculture, large amounts of nitrogen fertilizer are applied to corn fields. While this supports crop growth, about 40 percent of the nitrogen is lost. Some microbes convert nitrogen into nitrate, which washes into rivers and lakes. Other microbes turn nitrate into gases, including nitrous oxide, which contributes to climate change.
The researchers found that wild corn relatives naturally limit the activity of these microbes. When certain genes are active, plant roots release compounds that slow nitrification and denitrification. This keeps nitrogen in the soil longer and improves fertilizer efficiency.
To test whether these traits could work in modern corn, scientists studied special breeding lines containing small pieces of wild corn DNA. Field trials showed some lines reduced nitrogen-converting microbes by up to 50 percent. Laboratory tests confirmed that these effects were linked to changes in root chemistry.
A key concern was whether these traits would reduce yield. When the nitrogen-saving traits were crossed into hybrid corn, yields remained unchanged. The trait also proved to be dominant, meaning it worked regardless of which parent plant carried it.
“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.
These findings suggest farmers could one day grow corn that naturally conserves nitrogen, reducing fertilizer costs and environmental damage. This approach could help protect water quality, lower greenhouse gas emissions, and support long-term soil health.
Researchers say managing soil microbes through plant breeding represents a new direction for agriculture. By using ancient genetic traits, future crops may become more efficient and sustainable while continuing to meet global food needs.
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Categories: National