When it comes to on-site crop research and big-time farm shows, the Sunbelt Ag Expo boasts the largest around, where major companies and land-grant university scientists annually conduct research trials on more than 250 plots throughout Expo’s working 600-acre farm site.
“Our working research farm is what sets us apart from any other farm show in the country and really the world,” said Michael Chafin, farm manager of the Sunbelt Ag Expo Darrell Williams Research Farm, named in memory of longtime Expo farm manager Darrell Williams.
“We want this to be a place where research is done to find answers that growers can take back to their farms or communities and share it and improve their bottom lines.”
One place where Southeast cotton growers continue to struggle is with their decade-long battle against weeds resistant to well-established herbicides, which threatens conservation-tillage practices throughout the region.
Stanley Culpepper, University of Georgia Cooperative Extension weed specialist, conducts research at the Sunbelt farm site that shows cotton growers can still use conservation-tillage practices and not sacrifice weed control to do it, especially avoiding the problems of their No. 1 weed enemy: Palmer amaranth, or pigweed.
Herbicides continue to be the first line of defense against tough weeds. Most herbicide systems control Palmer by as much as 90 percent, Culpepper said, but Palmer amaranth populations are so high across Georgia that this level of control is not enough, especially in conservation-tillage, Culpepper said. Cotton growers can still use conservation-tillage, but they’ll need plenty of biomass to do.
Producing large cover crops to suppress weeds is nothing new. Culpepper uses a rye cover to show growers how to get Palmer down, but it’s got to be high rye, at least 7 feet tall or better by planting time in the spring. The rye can be rolled down to form a protective mat over the field, one that will stop the sunlight from getting to the Palmer seed that has been there from last year ready to strike. Palmer amaranth seed can’t germinate without sunlight.
Start on limited basis
“Some growers are uncomfortable with this practice and don’t believe they can manage the system. As is the case with all new practices, it is best start off with a limited number of acres, but most growers will actually be surprised how easy this system is to manage and the fact you actually have more flexibility than with most other practices,” Culpepper said.
Fungicides find bigger role on Southeast farms
With the increase in some commodity prices, the introduction of new diseases, and old ones getting worse, Southern farmers see the benefits of what a well-timed fungicide can do to protect yields.
Anyone who grows peanuts knows the need for fungicides, which the crop needs on a consistent schedule seven or eight times a season. But in recent years, Southern farmers have increasingly used fungicides on corn, cotton and soybeans and, it is working for them, Chafin said, and it’s working at the Sunbelt farm site.
“We have had, for the last few years, several trials on using fungicides to protect or even increase yields in corn and to see what well-timed fungicide applications can do to protect corn and cotton against what can be some devastating diseases,” said Chafin.
“Regardless of the fungicides you use, the end result can be economical for growers in certain situations.”
Less than a decade ago, UGA Extension specialists had limited recommendations for treating soybeans and field corn with fungicides, and certainly had none for cotton. “Today, my message to our corn and soybean producers is that each should anticipate and plan for at least a single fungicide application early in reproductive growth (first tassel, late bloom or early pod set),” said Bob Kemerait, University of Georgia Extension plant pathologist.
Where weather favors disease, crop growth is robust, and prices are excellent, “growers are wise to follow up with an additional fungicide application,” he said.
With the cool, wet start to planting this year, Kemerait said, Northern corn leaf blight showed up in early May, the earliest it has ever appeared in Georgia, setting the stage for fungicides in corn.
And where rust is a problem, he said, a single fungicide application on corn can increase yields by 10 bushels per acre; even more for soybeans.
Fungicides making money
“I think in corn and soybeans our growers have reached the stage where they are very comfortable using fungicides to make them money,” Kemerait said.
Where growers may not be comfortable using fungicides, though, is in cotton fields. But that’s changing with the increase in pressure from a disease called cotton target spot caused by Corynespora cassiicola.
“Using fungicides on cotton has kind of come out of left field. But for an increasing number of growers across the Southeast, the use of fungicides to manage target spot is of considerable interest now, but is also approached with uncertainty and a healthy dose of caution,” Kemerait said.
Cotton target spot last year, he said, stretched from Alabama to Virginia, and growers saw advantages to using fungicide in battling it in severe situations, noting that the disease can fast defoliate cotton when it hits early in a season. Fungicides can save up to 200 pounds of lint per acre.
Target spot, he admitted, can help cotton at certain times. A little defoliation late in the season can actually help prevent boll rot in rank-growth cotton, which is most often hit by the disease.
“Growers should scout their fields at the approach of first bloom to determine if target spot is present. From research conducted in Georgia, the optimum timing for an initial fungicide application is sometime between the first and third week of bloom. An additional fungicide application may be needed approximately three weeks after the first application,” he said.
Shooting for high-yield beans
Can Southeast growers, particularly in Georgia, Florida and Alabama, make 70 or 80 bushels of soybeans per acre, or more? Can they do it consistently? Maybe.
“If you don’t try, you aren’t going to get there, but at least we are looking at some things to try and get growers there,” said John Woodruff, retired University of Georgia soybean agronomist.
Woodruff and current UGA Cooperative Extension soybean agronomist Jared Whitaker are using the Expo farm to conduct research trials for high-yielding soybean varieties and cultural practices.
They are using the current UGA recommendations for soybean production in Georgia, but also looking to tweak those recommendations to help those growers who want to swing for the fence with higher average yields.
Interest in soybeans in the Southeast is growing, especially as prices remain higher than in previous years, making the commodity much more appealing to growers. But to really compete with other more established commodities like cotton and peanuts, soybeans need to average high yields to really payoff.
Woodruff notes that soybean growers in Mississippi and Arkansas have in recent years been able to consistently average 10 bushels or more per acre than Deep South growers, mostly by using indeterminate varieties. He thinks this can work for Deep South growers, too. They’ll just have to manage them differently than they are used to.
What are some of the tweaks they are looking at?
1) For early planting, growers need to think about using maturity Group V beans or indeterminate varieties like late MG IV or Early V. For early planting, plan to plant May 10-30 with determinate varieties. Think about using an indeterminate variety for April 25-May 15 planting.
2) Plant in rows 18 inches to 24 inches wide if deep tillage and deep soybean rooting can be attained with planting, and plant to get a final stand of 125,000 to 150,000 plans per acre.
3) Rotate behind corn. Fertilize in fall of the year ahead of soybeans. Plant a rye cover crop. Kill the cover in early March.
4) Pay attention to irrigation to reduce soil moisture stress during flowering and early pod fill.