John Grymes | 4/20/2006 1:17:16 AM
Much of South Louisiana is enduring a drought that traces back as much as a year or more.
"Parts of the state have been suffering for quite some time," said Jay Grymes, LSU AgCenter climatologist. "In the southern third of Louisiana, the dry spell goes back to the beginnings of 2005, and even sections of northern Louisiana have been dealing with dry weather over the past 12 to 15 months."
Grymes pointed out that in Baton Rouge, 12 of the past 14 months have had below-normal rainfall. The only two exceptions were August and September, which correspond to hurricanes Katrina and Rita. Much of south-central and southeastern Louisiana is showing a similar drought trend for the past year.
"Without the hurricanes, it could have been 14 consecutive months of below-normal rainfall," Grymes said. "This past March was one of the driest – if not the driest – Marches on record for a large portion of South Louisiana, and this extremely dry spring weather has persisted through the first half of April, as well."
Grymes said he is concerned about the next six weeks to eight weeks, because spring rains, which generally recharge soil moisture, haven’t happened.
"Vegetation that roots deeply won’t find much moisture," the LSU AgCenter climatologist said. "The deep soils are much drier than normal for this time of year. Typically, the soils during March and April are well-wetted, but current estimates suggest that soil-water content is running at 20 percent or less of spring norms."
Grymes said the effects of dryness now could be more serious in late May and June.
"We know La Niña is likely to be a culprit," he said.
The climatologist said La Niña is defined by a region of cooler-than-normal waters extending thousands of miles across the central equatorial Pacific Ocean.
This "cold pool" of Pacific waters causes changes in the atmospheric jet stream that flows above it. As the jet stream flows eastward, the La Niña effect is to divert winter and spring storm tracks northward over the United States. The common result is less rain over the Gulf Coast states.
"LSU research suggests that well-developed La Niñas lead to drier-than-normal winters and springs over South Louisiana in 80 percent of these events," Grymes said. "The South Louisiana drought of 1998-2000, which ranks among the most severe droughts of the 20th Century for that region, was largely a function of a prolonged La Niña."
The general consensus is that La Niña will remain intact into the summer, Grymes noted. That means current patterns of below-normal rainfall are likely to continue for the next several weeks at least.
"In fact, extended-range projections indicate that Louisiana rainfall over the next one to two months has a 70 percent to 75 percent chance of running near-normal to below-normal," he said.
"To turn things around, we need more than just normal rainfall, we need a run of wetter-than-normal weeks," Grymes added, cautioning, "But that’s just not in the cards."
There is never a good time for a drought, but very dry weather in the spring is particularly difficult, said LSU AgCenter horticulturist Dan Gill. Many plants are sending out new spring growth now, and drought stress can lower plant vigor and reduce growth.
"Spring is a major planting time, and newly planted trees, shrubs, lawns and bedding plants are particularly susceptible to drought stress since they do not have well-established roots systems," Gill said. "Home gardeners need to pay particular attention to any new plantings and make sure that they are provided with adequate water."
He said even established trees, shrubs and lawns will benefit from irrigation when the weather is severely dry, and it’s best to water deeply and thoroughly once or twice a week using sprinklers or soaker hoses.
"For newly planted trees, shrubs and bedding plants, watering two or three times a week may be necessary," he said.
Lawns need attention, too, said LSU AgCenter horticulturist Dr. Tom Koske. He recommends mowing lawns at a higher cutting height that is still within recommended limits.
"This allows for deeper roots," he said. "Try not to stress the turf any more than needed. It’s fragile."
Koske also recommends holding off on applying fertilizer until the soil has enough moisture to sustain growth.
"Now, the dry grass can’t use any fertilizer," Koske said. "Irrigate at least some to avoid severe wilting to avoid turf loss."
Farmers, as well as homeowners, are feeling the effects of limited rainfall.
On top of what producers went through with hurricanes last year, a drought is another issue fraught with financial difficulty, said Dr. Kurt Guidry, an economist with the LSU AgCenter.
"With all the difficulties surrounding 2005, many producers are in delicate financial situations and really needed 2006 to be a much-improved year," Guidry said. "If the drought continues to move through the growing season, the potential for high cost of production and low yields will affect producers both in terms of revenue and costs."
Going into the season, most producers’ cash-flow projections were modest, even assuming average to above-average conditions, the LSU AgCenter economist said. If the drought continues, it is "going to be a situation to cause additional financial difficulties for some of these producers."
With even a little rain at the right time, however, the drought could have minimal effect on yields, Guidry said.
"We’re still early in the growing season," he said, suggesting the drought may force some producers to move to other crops. "However, any unplanned change in either the producer’s revenue or cost projections could substantially affect potential profitability."
The drought also means recovery will be longer for rice fields that were flooded by the storm surge from Hurricane Rita in September 2005.
"A drought will just prevent salt from rinsing out of the soil," said Dr. Johnny Saichuk, LSU AgCenter rice specialist in Crowley.
Saichuk said earlier estimates were that the affected soil could recover in about 18 months, but that projection assumed normal rainfall.
Rice farmers aren’t alone in facing a difficult season if the dry conditions continue, Saichuk said.
"That’s not going to affect just rice," he said. "That will affect just about every commodity."
Crop consultant Chuck Greene said he’s spending as much time this spring empathizing with disillusioned farmers as advising them on agricultural practices.
"We’re in a bad situation," he said. "We’re so low in our water table that we’ve got saltwater coming up in our bayous. Every day the concern over salt increases more and more."
Sugarcane farmers would like to see 2 inches to 3 inches of rain "to set the fertilizer and get the cane to grow," said Dr. Ben Legndre, LSU AgCenter sugarcane specialist. "But at this time of the year we typically like to see drier weather."
The sugarcane specialist said that across the sugarcane-growing region, rainfall has been only about one-third of normal.
"We’re awfully dry," he said.
"The cane is rather stressed, and early growth is being delayed," Legendre said. "But it’s not critical yet."
Jay Grymes at (225) 578-6870 or email@example.com
Dan Gill at (225) 578-2222 or firstname.lastname@example.org
Tom Koske at (225) 578-2222 or email@example.com
Kurt Guidry at (225) 578-4567 or firstname.lastname@example.org
Johnny Saichuk at (337) 788-7547 or email@example.com
Ben Legendre at (225) 642-0224 or firstname.lastname@example.org
Rick Bogren at (225) 578-5839 or email@example.com