Sunbelt Expo Field Day showcases bumper crops

Many of the farmers, Extension specialists and researchers attending the annual Sunbelt Expo Field Day in Moultrie, Ga., were finding it difficult to contain their enthusiasm over what is being called one of the best cotton, peanut and corn crops in many years in Georgia.

While a lot still could happen between now and harvest, most observers at the field day were cautiously optimistic. "It’s the best peanut, cotton and corn crops I’ve ever seen at this point in the season," says Steve M. Brown, University of Georgia Extension cotton specialist.

"Some of the cotton crop was drowned out from the rainfall in June, and we have cotton at several different growth stages, but it’s a pretty good crop," says Brown. "We had some late cotton, but we’ve made up for much of that. We have the whole range as far as growth stages, with some cotton moving rapidly toward cut-out and some that is pre-square. But generally, the crop is moving ahead nicely and it looks great. Rainfall can make a world of difference."

Brown says the agricultural statistic service’s estimate of about 1.43 million acres of cotton in Georgia appears to be on the mark. "Some farmers left cotton and planted more peanuts, and others went in the opposite direction," he says.

In addition to cotton, visitors to this year’s Sunbelt Expo Field Day got an up-close look at more than 130 varieties of other crops, including peanuts, corn, sorghum and soybeans. The field day is a preview to the Sunbelt Agricultural Exposition, set for Oct. 14-16.

Cotton research at the Expo site includes looking at several fertilizer materials, says Glen Harris, University of Georgia Extension agronomist. "It’s interesting," says Harris. "With all of the rain we saw in June, we’re getting more questions about replacing lost fertilizer and about foliar feeding. It seems as though when Bt cotton first came on the scene, we stopped foliar feeding. Now, it’s slowly coming back."

Harris is conducting several foliar feeding trials at Expo, with both nitrogen and potassium. "A number of materials are available for foliar feeding potassium. We’re also looking at various rates and timing of sulfur, either at planting or side-dress at 10, 20 and 30 pounds per acre.

"We also continue to look at boron products. Our experience has been, that pound-for-pound, boron is boron. But we’ve seen slight differences in how boron is elevated in the leaf," he says.

In reviewing the growing season, Harris says he has seen a lot of "yellow cotton" this year. "That makes sense if the grower hasn’t side-dressed yet. Or, the nitrogen might be there, but the plant isn’t taking it up. I’m most worried about the grower who’s coming up short, and he’s at about the third week of bloom. That’s the time when we don’t like to put any more nitrogen on the ground — we prefer to go to foliar feeding.

"If a grower needs to make up 10 pounds of nitrogen or potassium, he can probably handle that. But if he’s very far behind that point, it’ll be difficult to make it up with foliar feeding."

Harris makes the following recommendations for replacing leached nutrients:

o Nitrogen is the fertilizer nutrient needed in the largest amounts by cotton and is also the most leachable. Consider increasing your side-dress nitrogen rate by 25 percent to replace lost preplant nitrogen. Re-sidedressing may be warranted but needs to be done before the third week of bloom to be effective. Foliar nitrogen can be effective anytime during peak bloom or shortly after.

o Potassium is not as leachable as nitrogen but can leach under extreme conditions in sandy soils. Additional potash can be applied with side-dress nitgrogen (easier with granular than with liquid) or with foliar applications. It may be easier to rely on foliar applications of potassium if you develop a problem compared to nitrogen.

o Sulfur is about as leachable as nitrogen. But unlike nitrogen and potassium, it’s not easier to foliar feed. Therefore, sulfur needs to be applied in preplant or side-dress applications. If not, a gypsum application with a high-clearance buggy may be your only chance of recovery.

o Boron is highly mobile in Georgia soils. With more Bt and stacked-gene cotton, some growers are applying boron in preplant or side-dress applications. Preplant boron applications this year are highly susceptible to leaching. Side-dressed boron is a more preferred soil application method. Boron foliar feeds very well and may be worth the trip alone if none has been applied or if leaching of preplant boron is suspected.

University of Georgia researchers also are looking at the problem of hardlock in cotton. Hardlock, says Extension plant pathologist Bob Kemerait, occurs when the cotton bolls open but the lint fails to fluff.

"With mechanical harvesting, that cotton basically is lost," says Kemerait. "For a long time, we in Georgia lumped hardlock into a form of boll rot. Florida researchers have looked at the problem, and they feel that it might be caused by a fungal pathogen. And they’ve reported great success from spraying Benlate."

Georgia researchers will be looking at three locations this year to see if they can get similar results from spraying a fungicide, he says. "Benlate no longer is available, but we’ll be using a similar material — Topsin M. We’re also looking at different chemical classes. We’ll start spraying at bloom and make some economical decisions on what’s best for growers. We’ll see if we get similar results to those in Florida," says Kemerait.

Cotton diseases seen most commonly during the early part of the 2003 growing season included shore shin, caused by Rhizoctonia solani, and wet weather blight, caused by Ascochyta gossypii, says Kemerait. Both diseases tend to be more severe where rainfall has been abundant early in the season.

"Thanks to our nematode roundup last year and the good efforts of our county Extension agents, we’re seeing more interest this season in managing nematodes in cotton. Growers are asking more questions about control, and we’re also finding that growers are more diligent in collecting nematode samples."

Within weeks following planting, Kemerait says he saw six to seven fields with serious root-knot nematode damage. "Nematode awareness is increasing among cotton growers as it should. It’s a major issue, and growers are more prepared to take the necessary steps with nematicides and with rotation to control nematodes."

The University of Georgia peanut cultivar demonstration at Expo includes 15 released varieties and three experimental lines, says Extension Peanut Specialist John Baldwin.

"I never would have thought five years ago that I’d see this many varieties," says Baldwin. "We have our standard varieties like Georgia Green, C-99R and ViruGard, and we have some Virginia varieties. We’re trying to get a handle on how some of these newer varieties will compare to the standard. We followed the Tomato Spotted Wilt Virus Risk Index for the most part, but we planted on April 30 to put a little pressure in the test."

Phorate insecticide was applied in-furrow, and the peanuts were strip-tilled into wheat stubble, in single and twin rows.

"We used Roundup to kill the wheat and then used Prowl and Valor pre-emergence, immediately after planting. We watered in those herbicides. These peanuts had no at-cracking sprays. We came back later with Cadre. Our main weed problems at this site are nutsedge, morningglory and pigweed. This is probably the best weed control we’ve seen since we began working here in 1987."

The peanuts, says Baldwin, will be rated for disease resistance, especially to tomato spotted wilt virus.

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