Paul L. Hollis

August 1, 2007

8 Min Read

Row after row of vigorously growing cotton, peanuts, corn, soybeans and other crops on display at the 2007 Sunbelt Expo Field Day gave little hint of the magnitude of the drought that has plagued the region. But Farm Manager Darrell Williams has seen several firsts this year due to extremely dry weather conditions.

“This is the first time I've had to irrigate the soil just to plant and bed,” says Williams, who has been with the Expo since 1980. “And all of this irrigation has made these crops more expensive to grow, especially considering the cost of diesel. We've used a lot more water this year, particularly for corn.”

Scattered showers finally began to fall in the Moultrie, Ga., area in June, he says, and the timing could not have been better. “The condition of the crops is good now, and everything appears to be on schedule,” says Williams of the Expo's 550-acre working farm.

Another first this year, he adds, is that the Expo has no hay to sell. “We had to water hay this year, and we still have a list of people wanting to buy it, but it's all been sold,” he says.

More than 400 visitors attended this year's Sunbelt Expo Field Day, getting an up-close look at several new varieties of crops in addition to cutting-edge technologies to apply to those crops.

The emerging market for renewable fuels has encouraged the National Peanut Research Laboratory in Dawson, Ga., to continue looking at growing low-input peanuts for use as biodiesel. Biological Science Technician Gordon Bonner says six varieties of peanuts were planted this year to compare cost effectiveness for use as biodiesel — Georgia Green, Georganic, GA 045, GA 03L, FL 07 and DP-1.

To make peanut biodiesel more cost competitive, researchers are utilizing technology such as conservation-tillage and selecting varieties with high tolerance to multiple diseases. The peanuts are managed with a budget of less than $200 per acre. Plots this past year yielded from 900 to 3,000 pounds per acre.

In addition to field production, the team from the National Peanut Lab has completed construction of a small-scale peanut biodiesel refinery, like farmers or small cooperatives of farmers could build. The idea is to bring peanuts from the field directly to the fuel tank at the local level. The new refinery can make 5,000 gallons of B100 annually, enough to run a fleet of tractors and trucks when blended 50 percent with petro diesel. The economics of processing and refining will be examined closely so that farmers and others can adopt the technology with confidence.

The University of Georgia's Extension Peanut Team featured its “Variety Showcase” at this year's Expo Field Day, giving farmers the opportunity to compare 21 varieties planted side by side.

“Growers now have a long list of varieties from which to choose,” says John Paulk, research assistant. “We can choose varieties based on maturity, disease resistance, high-oleic chemistry or growth habit. We have a lot of new varieties with prominent main stems to make digging easier, and we have more compact plants. Georgia Green — first released in 1995 — continues to command the lion's share of the market. We still have more acres in Georgia Green than in any other variety. But it is now the least disease-resistant plant we have.”

With the addition of more disease-resistant peanut varieties, growers want to know if they can plant earlier than the recommended planting window, says Paulk. “We're looking for an answer to this question with a planting date study, planting some peanuts on April 18 and others on May 18. Last year, at one location, we showed a 500-poind yield increase between planting in mid April versus planting in mid May.

“We're looking at this same test at three other locations. We're skipping to the mid-maturing varieties because we don't recommend planting late-maturing varieties after May 20. We're looking at Georgia Green, Carver, AP-3 and several new varieties,” he says.

Reviewing some of the newer varieties, Paulk says AT-215 is from Agra Tech and is considered a possible replacement for ViruGard. “It's an earlier peanut, coming off about 14 to 21 days ahead of Georgia Green. It has better resistance to tomato spotted wilt virus than ViruGard. It has a great growth habit with very vigorous seed. This variety also has a prominent main stem, a dark color and some leafspot resistance,” he says.

Also from Agra Tech are 3081R and 3085RO, he adds. “From the University of Georgia, we have Georgia Greener — with a dark canopy — and GA 066 — with a dark green color and prominent main stem, making it easier to dig. Both are mid-maturing peanuts,” he says.

USDA has a numbered peanut variety — C7241915 — that is nematode resistant as well as being highly resistant to tomato spotted wilt virus, says Paulk.

Also featured at the Sunbelt Expo Field Day were more than 30 soybean varieties, including a test comparing early planted soybeans with traditionally planted beans. “With an early system, we plant Maturity Group III and IV soybeans in late April. Traditional soybeans are planted in mid-May,” says John Woodruff, University of Georgia agronomist.

Growing Group III and IV soybeans much like corn has produced yields in the 50 to 60-bushel per-acre range in the Delta and in the upper Southeast, but Woodruff is shooting for even higher yields. He is also looking this year at various sunflower varieties.

“The oilseed market is very attractive, with soybeans trading at well above $8 per bushel and oilseeds like sunflower trading at about 18 cents per pound, about two times what it has been in the past 10 years. Oil is in high demand in Southeast Asia and throughout all parts of the world. There is also much interest in biodiesel,” says Woodruff.

To compete with other crops for irrigated land in the Southeast, growers would have to yield better than 50 to 55 bushels per acre with soybeans, he says. “We're looking at the early system soybeans as a possibility as well as traditional beans planted grown with intense management.

“One of the problems with traditional soybeans is that even if you do everything right to make high yields, they tend to lodge. Then, the plant sheds a lot of leaves and aborts a lot of fruit. If you plant varieties that do not lodge and combine that with high inputs, you have a better chance of making 66 to 70-bushel yields. We're making 65 bushels with our best effort but we want to do better,” says Woodruff.

The University of Georgia Extension Cotton Team is looking at several aspects of production at the Expo farm, including fertilization and insect control. “The name of the game in cotton production is nitrogen, but nitrogen prices are up, and we're seeing shifts away from certain products like ammonium nitrate,” says Glen Harris, Extension soil fertility specialist.

With more granular urea replacing ammonium nitrate as a broadcast sidedress source, a major focus is on reducing volatilization losses using urease inhibitors, says Harris. Nitrification inhibitors and other additives to reduce nitrate leaching also are available, and some of these products contain both urease inhibitors and nitrification inhibitors, he says.

“Not only is this going to be confusing to growers, but it is also going to take some time to determine exactly which of these products work under which conditions,” he says.

There's some interest, says Harris, in slow-release or polymer-coated materials designed to release nitrogen throughout the season. “The idea behind these materials is to put it all on at planting so you won't have to come back and sidedress,” he says.

Insect control research is focusing on stink bugs and cotton aphids, says Extension entomologist Phillip Roberts. “We're participating in a regional stink bug project along with other Southeastern states. There are two objectives. One is to better define the time during the growing season when cotton is most susceptible to stink bugs. There are certain times of the year when bolls are more susceptible, and we've made a lot of progress in understanding that critical window,” he says.

Some of that research is being incorporated into new thresholds for treating stink bugs, says Roberts.

“We're also looking at cotton aphids. In 2006, there were questions about whether or not we should have treated for aphids. We haven't yet seen a yield response from treating for cotton aphids, but we're looking at various timing,” he says.

Discussing the National Peanut Research Laboratory's Irrigator Pro scheduling system was Staci Ingram. “Irrigator Pro for peanuts has been around for many years,” says Ingram. “By taking minimum and maximum soil temperatures, and based on where the crop is physiologically, you can determine when and how much you need to irrigate your peanut crop.

“The Georgia Cotton Commission asked use to develop a model for cotton, and because corn is grown in rotation with cotton and peanuts, we also developed a model for corn. When we monitor soil temperatures, we use soil moisture sensors placed in the soil at 8, 16 and 24-inch depths so we can determine the actual soil moisture levels at those different depths for the root zone. We use meters to tell us the readings at different depths, and we put those readings into the software which recommends whether or not to irrigate,” she says.

About the Author(s)

Paul L. Hollis

Auburn University College of Agriculture

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