COLUMBIA, Mo. — Tighter corn margins mean Midwest producers will manage nitrogen applications as closely as ever in 2016. For future years, researchers are finding possible answers for corn nitrogen needs from an unlikely ally: Foxtail.
Corn fertilizer costs throughout the region averaged $130-$165 per acre this year, according to budgets developed by crop consultants and university specialists. That includes costs of nitrogen, phosphorous and potassium.
This year’s fertilizer cost is estimated at $148 on central Illinois farmland with high productivity, according to University of Illinois economist Gary Schnitkey. He projected in July that fertilizer costs will decline by $10 next season. That savings comes from slightly lower fertilizer prices and lighter nutrient applications because of lower corn prices, he said.
Some producers are looking to production practices to capture efficient nutrient use. Splitting the spring nitrogen application can result in better utilization when nitrogen is applied at optimum soil temperature and moisture levels.
The additional yield boost from split application can offset the cost of the second field trip, according to Corn Split N, an online decision tool. Nitrogen-saving practices are attractive for both economic and environmental reasons. Better uptake by the plant results in less nutrient runoff potential.
While produ-cers mull their nitrogen needs for next year, researchers at the University of Missouri and in Brazil are searching for grass genes that could reduce corn nitrogen applications in the future. The work focuses on bacterial nitrogen fixation, a process more commonly associated with legumes than grasses.
"The plants don’t fix atmospheric nitrogen by themselves. They need some help," said Fernanda Amaral, postdoctoral researcher in the Bond Life Sciences Center at MU.
Amaral is studying how some genotypes of the grass Setaria viridis – commonly called foxtail – interact with Azospirillum brasilense, a nitrogen-fixing bacteria. "These bacteria are already being used commercially in Brazil to improve crop (legume) plant growth," said Amaral.
She worked on the project with Gary Stacey, an MU professor of plant sciences and biochemistry, as well as researchers at two institutions in Brazil. The research goal was to determine if grasses also used nitrogen fixed by those bacteria. That meant exposing the setaria to a radioactive isotope, a process completed at Brookhaven National Laboratory in New York.
The grass was planted in soil with no nutrients. Then, the researchers used the radioisotope, Nitrogen 13, to track how quickly the grass took up nitrogen from the bacteria. Their results showed the setaria was able to use nitrogen from the bacteria in a robust way.
Amaral is now looking into the plant genetics behind the process. "We have the evidence that the grass plants are using the nitrogen, so we want to know what genes are involved in the process," she said.
She is working on a detailed analysis of the genes researchers think are most important.
After identifying the most important genes, researchers could develop a transgenic setaria grass that best uses the nitrogen fixed by the bacteria. Such work might then be applied to commercially important grasses, like 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," said Amaral.
