Farmers with rice fields in Louisiana's southern Vermilion Parish should make sure salinity levels in their irrigation water are safe, even if their soils show low salt levels, LSU AgCenter scientists say.
The LSU AgCenter is recommending that farmers avoid planting in southwest Louisiana fields flooded last year by Hurricane Rita's storm surge if the salt levels in soil exceed 750 parts per million.
“We still feel fairly comfortable with 750, assuming you have good fresh water,” said Steve Linscombe, a rice breeder and regional director for the LSU AgCenter.
Linscombe pointed out, however, that salt levels can vary with soil samples taken at different locations within a field. “When we say 750, that's the most you need to see in that field.”
LSU AgCenter rice specialist Johnny Saichuk said using residual herbicides such as Command might not be a good idea on fields with salt levels near the 750 ppm level.
“I would look at good old propanil, because you know what it's going to do,” Saichuk said.
Linscombe agreed, explaining that chemicals that put stress on a plant, such as Command, could harm crops permanently in fields with moderate salt content.
As for using salty water, Jason Bond, an agronomist at the LSU AgCenter's Rice Research Station near Crowley, said it could be done on a limited basis.
“You can do it if you have to, but don't keep doing it,” Bond said.
Howard Cormier, an LSU AgCenter county agent in Vermilion Parish, said most farmers will face that dilemma. “Most of the water we have, even from wells, will have salt in it,” he said.
Cormier said a U.S. Army Corps of Engineers official told him it could take up to 18 months to flush salt from the marsh. Salt water continues to flow into White Lake at the Schooner Bayou Control Structure, he said.
Bond said soil and water in the area would have less salt if rainfall had been normal this winter.
The agronomist also said greenhouse testing at the Rice Research Station showed rice could sprout in soil with moderate salt levels — around 1,000 ppm — but that it withered after the plants were flooded.
Mark Shirley, LSU AgCenter aquaculture agent, said crawfish farming in Vermilion Parish also has been affected. “The crawfish situation isn't a whole lot brighter than the rice situation,” he said.
Retired farmer Buster Griffin of Henry, La., said he's not sure if he will plant this year. “I'm looking at it hard,” he said.
Griffin's son, Scott Griffin, said he will plant 250 acres to 400 acres of the 800 acres he grew last year. He said some land with low salt levels lacks good irrigation water.
The water quality issue is affecting the limited crawfish production, he said. “We can't keep water in the ponds because of bad water in the canals.”
Farmer Steve Hebert of Cow Island, La., said he will plant roughly half of the 1,200 acres of ground he planted in 2005. He said his soil tested above 900 ppm and even reached 4,000 ppm to 5,000 ppm near Esther, La.
Hebert said some of his fields are barren of any vegetation, including weeds.
“And it's not the winter that killed it,” he said.
Farmer Pat Menard of Henry said he won't plant any of his 200 acres because soil testing showed salt exceeding 3,000 ppm. He's been forced to move his cattle to pasture south of Maurice, La.
“If we can't plant rice this year, we won't have crawfish next year,” Menard said. “So you've got two years with no crawfish.”
Henry Broussard of Henry said he won't plant any of his 300 acres this year either, because his soil tested at 6,000 ppm. He said he had a good catch in his crawfish pond, but it wasn't crawfish.
“We caught two-and-a-half dozen crabs in 15 minutes,” he said.
Farmer Jimmy Domingue, also of Henry, said he'll probably plant 150 acres this year, down 350 acres from last year. Some soil had a 7,600 ppm salt level, he said.
“It took me 15 days to pump the water off from Rita,” he said, adding that his pumps ran 24 hours a day to move 55,000 gallons a minute.
Bruce Schultz is a writer for the LSU AgCenter. e-mail: firstname.lastname@example.org