NATCHEZ — Conservation efforts by farmers may be reducing a Connecticut-sized dead zone in the Gulf of Mexico.

A U.S. Department of Agriculture study, released Wednesday, found that the amount of nitrogen leaking into the Mississippi River is 21 percent less than it was in 2009. The study also found that phosphorous leakage was reduced by 52 percent.

The nutrient leakage builds up at the mouth of the Mississippi and forms what scientists call a dead zone each year. This year’s dead zone covered 5,840 square miles, roughly the size of Connecticut.

LSU AgCenter Extension Agent Sara Nuss said the dead zone consists of a high concentration of nutrients from fertilizer. Nutrients zap oxygen from the water, making breathing difficult for fish.

Concordia Parish’s $122 million agricultural industry may be a part of the problem.

“The nutrients leak out of the field, then gets into a ditch, then ultimately end up in the river and go into the Gulf,” LSU AgCenter Extension Agent Dennis Burns said.

But the news isn’t all bad. The study’s results show that farmers are working to reduce the amount of leakage, Natural Resources Conservation Service state conservationist Sarah Haymaker said.

“We need to keep up the momentum by providing scientific and technical expertise that supports conservation in agriculture,” Haymaker said.

Nuss said Concordia Parish farmers have already begun changing the way crops are harvested.

She said the largest cause of runoff is applying an excessive amount of fertilizer.

As a result, many farmers have begun mapping soil texture.

“Different soil textures have different abilities to leach nutrients,” she said. “The nutrients from fertilizer may seep out easier through certain kinds of soil.”

Forgetting to cut the grass may also be a good way to prevent nutrient runoff, Burns said.

“Instead of just a regular dirt ditch, it is beneficial to let grass grow in ditches,” he said. “The grass absorbs the nutrients to a certain extent and prevents nutrients from flowing into the Mississippi River.”