The Darrell Williams Research Farm at the Sunbelt Ag Expo continues to be a major base of on-site research for University of Georgia Extension specialists. During the recent field day, fertility, variety trials and disease and pest management for all major Southern agronomic crops were just a few of the areas covered.

As the yield potential continues to rise for new crop varieties, maximizing plant nutrients becomes a top priority for growers, says Glen Harris, University of Georgia Extension agronomist-soils and fertilizer.

“We do a lot of our cotton fertility research at the Sunbelt Ag Expo site, and this his year we’re conducting some potash and nitrogen studies. Some of you may be wondering what’s left to talk about with nitrogen. It never hurts to have plots like that to remind folks what’ll happen if you don’t have nitrogen. Our research plots are 4 feet wide by 40 feet long, and we have 11 different side-dress nitrogen materials out here to compare,” said Harris at the Expo Field Day on July 10.

Harris says he’s looking at various solid materials, including urea, ammonium nitrate, polymer-coated urea, and urea with a urease inhibitor. Liquid materials include 28-00-5 and 18-00-3 without the sulfur and a material that has an equal amount of urea and ammonium nitrate in the liquid form, he says.

“This is my second year of looking at these, on both corn and cotton, and I believe we’re starting to see some trends. I can say now that a lot of the liquids look more consistent than urea by itself. Hopefully, we’ll have a lot of good information to help guide farmers on which nitrogen materials to use on cotton,” says Harris.

He’s also conducting trials with foliar potassium on cotton. “There are currently a lot of potassium issues in cotton production,” says the agronomist. “We normally spray potassium nitrate, but like ammonium nitrate, it’s getting harder to get. So we’re looking at some alternatives, including potassium thiosulfate, potassium acetate, maybe even some spray grade of potassium chloride which is like urea potash in a spray grade. Some of that work has been done in the past but not recently.”

Harris also will be comparing the materials for burn potential when foliar feeding.

“We’re also comparing lime materials – there’s calcitic versus dolimitic – and there are a lot of byproducts available to farmers that contain lime. There’s wood ash, and one that comes out of a pulp and paper mill that’s recycled paper. We’re looking at that for the first time this year.

Some folks are promoting some high rates of lime – 10 to 20 tons per acre. Personally, that sounds crazy, but I’ve put out a trial this year where we follow Extension recommendations of 1 to 2 tons versus 5 and 10 tons of lime. We’ll take it out long-term with cotton, peanuts, soybeans and corn.”

Researchers also are looking at different forms of calcium on peanuts – gypsum, fine limes and calcium chlorides through the pivot, says Harris.

“There’s a big push towards producing high-yield corn and splitting up nitrogen applications through the pivots. We’re looking at applying the right amount of nutrients at the right time to make 300-bushel corn. We made 270 last year, and we’re shooting for 300 bushels.

“I don’t know if splitting up nitrogen through the pivot will make you more corn, but you will be able to make more corn with less nitrogen because you were more efficient when you split it up. You might be able to make 300 bushels of corn on 300 pounds of nitrogen where if you don’t split it up, you might need 350 pounds of nitrogen. We’re trying to save growers money by being more efficient.”

New peanut varieties evaluated

The Sunbelt Ag Expo research farm continues to be a primary proving ground for new peanut varieties, says John Paulk of the UGA Peanut Team.

“We continue to evaluate new varieties here at the Sunbelt Ag Expo, as they are released, under different tillage and different row patterns and see under which conditions they perform the best. So when these varieties hit the market, you can feel confident in planting them in certain situations,” says Paulk.

The Sunbelt site is a sister test to another one in Tifton where researchers are comparing twin and single row production, he says. “At Tifton, we also throw in the tillage aspect, comparing twins and single rows on conservation and conventional tillage,” he says.

There are several new peanut varieties that are garnering interest, says Paulk, including TUFRunner 511 is from the University of Florida. “It has similar seed size to Georgia-06G, so it’s a larger-seeded runner. It’s about a 140-day peanut, and it’s high-oleic. The variety Georgia-12Y is also starting to make a name for itself and for good reason. It has had phenomenal yields for us. You can tell which peanut is Georgia 12Y when you drive by it. It has an extremely prominent main stem. It looks like a 2-by-6 turned sideways is laid on top of it. We’ve had it in trials for two years now, and I think there was an extremely limited amount of seed available this year. It should be available next year. We’re probably looking at another year down the road on TUFRunner 511.

“Georgia-13M also is in the pipeline. It’s a medium-size, high-oleic runner peanut. It will be a replacement variety for Georgia-09B. It yielded better than Georgia-09B in all trials, and it should be available in 2015.”

Researchers also are looking at a modified boom sprayer in peanut fungicide applications, says Paulk. We’re using a combination of 80-degree and 40-degree spray tips to concentrate a fungicide directly over the row. We’re applying more fungicide right over the row and less in the row. This is our first year of doing this, and we’ll be looking to see how it works out.”

Trials at several locations in Georgia are focusing on peanut row spacings in 30 and 36-inch rows, twin rows, and different seeding rates with the various varieties in our trials, he says. “We’re also looking at peanut rotations with cotton and corn, and we’ve even got soybeans and bahia grass in some of our trials. In addition, we’re taking a close look at inoculants in peanuts.”