Researchers at Iowa State are developing new innovations to help save farmers both money and the environment.

Recent precision farming trials show corn producers could substantially reduce the use of commercial fertilizers by delaying nitrogen application until after the plant emerges from the ground.

“The primary reason is that delaying applications minimizes nitrogen loss during spring rainfalls,” said Alfred Blackmer, professor of agronomy. Nitrogen is an essential fertilizer when growing corn, he said.

Blackmer and three graduate students worked with private farmers in Iowa to conduct research on nitrogen application on corn crops.

“The results of this research will help farmers do a better job of managing nitrogen,” Blackmer said. “It’s to their own benefit that more nitrogen ends up in the crop than in the outside environment.”

Thirteen fields were used in the study. All had grown soybeans the previous year. Nitrogen was applied in various strips at rates of 75 pounds per acre and 125 pounds per acre after the corn plants were three inches out.

Blackmer said the nitrate form of nitrogen, which is usually present in fertilized soils, moves fast in rain and leaches out into groundwater, streams and rivers.

“By applying nitrogen after the spring, when Iowa receives most of its rainfall, water pollution will be less of an environmental problem,” Blackmer said.

The testing strips were harvested by farmland owners and operators who used combines equipped with yield monitors and global positioning system receivers.

Brad Vandewoestyne, graduate student in agronomy, helped coordinate the farmers involved in the trials to set up the experimental designs for their fields.

“By doing these trials we can help farmers understand how much nitrogen to use in their fields,” Vandewoestyne said.

The field trials used several analyses to determine yield differences within the field. Researchers used remote sensing, digitized survey maps, differential elevation maps and maps of electrical conductivity.

The crop profit was equal in strips with both application rates. The average difference in yield over all the sites was about four bushels per acre.

Blackmer said applying fertilizer at a rate of 100 pounds per acre after the plant emerges is a fairly safe range for farmers.

Iowa State has been doing nitrogen research trials for the past ten years. The trials are still being conducted to learn new information to solve environmental problems and keep corn yields profitable.

Vandewoestyne said sharing this information with farmers will help corn growers use fertilizers more effectively and improve the environmental effects of nitrogen.

Blackmer said information found from this particular research is being published in several trade journals and the Iowa State Integrated Crop Management newsletter, which is distributed to farmers and consultants that keep up with the latest farm research.