Iowa State agriculture researchers believe they have the answers to cut back on excess nitrogen fertilizer in the environment. Now, they just need to convince Iowa farmers to use their new techniques.

At a seminar held Wednesday, Alfred Blackmer, professor in agronomy, said new research shows if farmers spray nitrogen fertilizer on their corn fields in the spring rather than the fall, they will significantly reduce the amount of fertilizer used on the field.

“There is about 1 million tons of nitrogen being dumped on fields every year,” Blackmer said. “With the new tools, we think it’s possible for farmers to reduce their input by possibly one third, without any significant loss of yield.”

Nitrogen fertilizer costs Iowa farmers about half a billion dollars a year, and right now most of them can’t afford it because of the poor market prices, he said.

Blackmer said new techniques, including the late-spring test for soil nitrate and the corn stalk test performed at the end of the season, are helping farmers estimate how much nitrogen is needed for the field.

The late-spring test measures the amount of nitrogen in the soil before the corn begins to absorb it. Blackmer said it is taken when the corn reaches 6 inches and reveals how much nitrogen is available for the crop.

“Use of this test should help corn producers manage nitrogen to increase their profits while reducing environmental degradation,” he said.

The corn stalk test is performed at the end of harvest on the lower stalks left in the fields.

One of the main reasons Blackmer is concerned about fertilizer is the damage caused to the environment by the excess.

The excess fertilizer gets washed into the Mississippi River and sent down to the Gulf of Mexico. There, the fertilizer causes low-oxygen levels, or hypoxia, in the water and kills off much of the aquatic life in the area, creating a “dead zone.”

It is estimated Iowa and Illinois are responsible for 35 percent of the nitrogen dumped into the river each year, he said.

“If we make [fertilizer] much more efficient, we will decrease the environmental concern,” Blackmer said.

Dana Diennes, field project manager, is conducting an environmental study along with a team of scientists. They are trying to prove nitrogen application in the spring works as well as application in the fall.

“We have to show the hard economic benefits to the [farmers] in order for them to change,” Diennes said. “They have little or no room to take risks with their crops.”

He said three main reasons farmers won’t change their fertilizer methods are they can’t count on good field conditions in the spring, co-ops and other nitrogen dealers offer huge discounts in the fall, and they worry about compacting soil hurting the yield.

Through education and research, the professors hope to change the farmers’ minds.

“We are in the third year of the program,” Diennes said. “We have already seen a significant reduction of nitrate compared to the farmers’ normal practices.”