Currently available technology and cultural methods can be used by growers to reduce inputs and increase income in cotton production, contends David Wright, University of Florida Extension agronomist.

“One thing we can do in the Southeast is to use starter fertilizer,” says Wright. “We've found that we get a good response to starter fertilizer on sandy soils. This is more of a soil response than the varietal response we usually see in cotton. If you apply a high-enough side-dress rate of nitrogen on sandy soils, you'll still get an increase with starter fertilizer.

“If a grower is farming on loamy soils, and he's using a minimal rate of side-dress nitrogen, he still can get a response to starter fertilizer, especially if he's trying to minimize nitrogen inputs for the cotton crop. Starter fertilizer may be a way of minimizing the side-dress nitrogen while still getting a response to the starter.”

Producers also should pay careful attention to nitrogen rates and timing, says Wright. Research has shown that top yields are achieved by applying nitrogen at about the first square stage, he adds.

“In years when we've had hard lock, we've reduced it by 41 percent by applying three to four ounces of this material after squaring. We also have increased boll numbers by up to 15 percent in some years. Also, yield increases have been as high as 35 percent, but there's still a lot of work to be done on this material.”

“We've conducted research where we stressed the plant up until the third week of bloom and then applied nitrogen. Generally, we've seen no yield increase from those late nitrogen applications. If you're in the third week of bloom, and you have a good crop set, our data from several years has shown that you don't increase yields. In many cases, we may decrease yields and cause more hard lock,” says the agronomist.

Cotton also can respond to sulfur, especially in sandy soils, he adds. “If the clay layer is 10 inches deep or less, we usually don't see a response. On the sandier soils, however, we do see a response. We've seen increases of one bale by adding 35 to 40 pounds of sulfur. We've used several forms of sulfur, including ammonium sulfate and even gypsum, which is used in peanuts as a source of calcium.

“Two-hundred pounds of gypsum will supply 35 to 40 pounds of sulfur. We've seen one-bale increases with the use of gypsum in cotton production.”

Conservation-tillage can also be used by growers to reduce inputs and increase income in cotton production, notes Wright.

“Conservation-tillage is being adopted on a wide scale by Southeastern cotton growers. We've seen strip-tillage with Roundup Ready technology resulting in economic increases of as much as $20 per acre.

“In the deep South, where we have sandy soils, we see a lot of sand blasting in conventional cotton production systems. We lose stands and are forced to replant. Generally, we've seen equal or better yields when comparing conservation-tillage systems to conventional systems.”

Cover crops, he continues, are very important to the success of conservation-tillage systems. “Often times, we use previous crop residue or winter weeds. It's very important, after you get into a system, to consider managing a cover crop. Where we have used a wheat cover crop and allowed it to head out, we've seen a difference in the soil temperature of as much as 25 degrees. This is the temperature underneath the mulch as compared to the surface of the conventional planting system.

“This leads to cooler plant temperatures by as much as five to six degrees. This results in much less stress on the plants. In addition, we've seen increases of as much as 40 percent in the soil moisture content of conservation-tillage systems. With these heavy mulches, we've seen yield increases of as much as 15 to 20 percent.”

Turning to more recent technology, Wright says he and other researchers have been working with the Harpin Technology (Messenger) for the past four years with positive results.

This technology, he explains, activates several plant pathogens.

“In years when we've had hard lock, we've reduced it by 41 percent by applying three to four ounces of this material after squaring. We also have increased boll numbers by up to 15 percent in some years. Also, yield increases have been as high as 35 percent, but there's still a lot of work to be done on this material.”

e-mail: phollis58@mindspring.com