It's an innovation that fish and farmers alike can get behind.

For the past four years, Tulane University has been asking inventors to pitch their ideas to help farmers use less fertilizer. Throughout much of the Midwest, excess fertilizer washes off into streams that eventually drain into the Gulf of Mexico, where nitrogen feeds the algae that cause the annual dead zone.

The dead zone — which grew to the largest size ever last summer — wreaks havoc on Louisiana's seafood industry since shrimp, crabs, fish and other species can't grow in areas where algae bloom then die, consuming the oxygen in the water.

The dead zone, also known as hypoxic areas, can be particularly damaging to young organisms, and those that do survive are likely to be smaller, scientists have said.

Over the summer, the four top teams in the Tulane challenge each got 25 acres of corn fields in Tensas Parish to test out their ideas. The million dollar purse was awarded to a group from Cornell University in a ceremony Thursday afternoon.

Cornell said its technology, which they dubbed Adapt-N, tells farmers how much fertilizer their fields really need so they don't spread it on too thick, explained team leader and soil science professor Harold van Es.

"We can make sure that all the nitrogen ends up in the crop," rather than the water, he said.

Judges from six Mississippi River states and farm-heavy Indiana looked at nitrogen measurements at the test sites to make sure fertilizer wasn't being wasted. They also checked the corn yield, since farmers won't want to try a new method if it kills off too many of their crops. Finally, the judges considered how much it costs to implement each of the proposals, said Leah Berger Jensen, Director of the Tulane Nitrogen Reduction Challenge.

All the teams' solutions were economically viable and would be advantageous for farmers, she said.

Farmers don't want to spread fertilizer that just gets washed into the Gulf instead of feeding their plants, Jensen said. And the agricultural sector knows that eventually the government is going to implement measures to limit nitrogen runoff. Right now there are unmet goals and unenforced guidelines, but as the dead zone grows, conditions will change, she predicted.

"At some point stricter regulations will be put into place," Jensen said.

Adapt-N works by helping farmers plan and track their needs.

Farmers input data about the composition of their soil and at the start of each season they include information like their planting date and tilling practices. Adapt-N tracks the weather and let the farmer know when it's time to spread more fertilizer and when the fields have enough without needing to collect samples, van Es explained.

The start-up that licensed Adapt-N was recently purchased by an international agricultural firm, so the software will be available for sale worldwide in time for the next planting season, he continued.

University board member and contest sponsor Phyllis Taylor said she hoped the event would promote research on an issue that hits close to home but also affects populations around the world. The contest sparked an international discussion, with proposals submitted by teams from as far away as China, Brazil and India, said University president Mike Fitts.

"For me, this is an incredible moment in the history of Tulane," he said.

Van Es and others stressed that it will take more than one approach to reduce nitrogen pollution.

Those attending Thursday's awards ceremony at the Tulane River and Coastal Center near the Port of New Orleans included Mead Hardwick, a partner at the family farm in Tensas Parish that hosted the researchers .

In a video of the farm shown at the ceremony, he expressed his excitement about the innovations developed on his land but noted that there's room for even more ideas.

"What's happening here isn't going to solve the problem on it's own," he said. "It's one cog in the wheel."

Follow Steve Hardy on Twitter, @SteveRHardy.