Saltwater Threatens Louisiana’s Citrus Crops

Briny ground water is killing thousands of trees in the fertile citrus groves of Plaquemines Parish--a long, narrow spit of land between New Orleans and the mouth of the Mississippi River.

About 200 farmers grow oranges and other fruit in the parish, bringing in about $3.6 million a year. But experts say the land, where citrus trees have been grown for 300 years, may be unfarmable soon because saltwater is seeping in from the Gulf of Mexico.

Saltwater intrusion has been worsening during the last three decades because of land erosion, the loss of the barrier islands and seeping salt from canals.

The salt is like poison to the trees on Nathan Sims’ 30 acres.

Four years ago, he planted 3,750 trees. Already, 522 are dead, not producing, or dying from saltwater.

As Sims walks among his trees, he snaps off dead twigs--one of the symptoms of saltwater damage. And he points out other signs: the lack of fruit, falling leaves, stunted growth, dead trees.

About 80% of groves in the parish sampled show signs of saltwater damage, extension agent Alan Vaughn said. The salty ground water is just 3 or 4 feet from the surface.

“We have to get the salt away from the root system,” Vaughn said. “It is a very costly problem in Florida and Texas. . . . They can’t economically fight it, so they move the grove. We don’t have that luxury.”

Southern Louisiana is the only part of the state warm enough to grow oranges commercially.

Sims fights a costly battle to keep the saltwater away. He installed a $100,000 irrigation system, piping in water from the Mississippi River to flush the salt out.

He dug deep trenches to channel runoff water. He brought in engineers to advise him. He pumps compressed air into his roots to bring up the soil and puts a fungicide on the roots to protect them from salt.

But he acknowledges that few of his fellow growers can afford to do what he has done.

“I’m not one to quit,” he says.

Experts are working on developing salt-tolerant trees and testing systems of pipes designed to drain saltwater away from the trees before it reaches the roots.

Wayne Bourgeois, an associate professor at the Louisiana State University Agricultural Center’s Citrus Research Station near Port Sulphur, said that if a solution is not found in the next three or four years, the salt will kill the citrus trees.

“We found a way to solve freeze problems. We can find ways to solve insect and disease problems,” he said. “But we’re not sure how to solve this problem in the relatively short time we have.”