From near virgin cotton country in northwest Texas to century-old farms in the Deep South, rotating cotton with corn continues to yield more pounds per acre and strong corn production on the side.
New cotton growers like Mike Friemel, Groom, TX, are seeing both crops flourish more on land where cotton was recently unheard of. In Mississippi, Alabama and other southern regions, primary cotton producers enjoy near 15% better cotton yields in a cotton-corn rotation program. There are also benefits to cotton, and from a soybean-cotton rotation.
Friemel, a long-time irrigated corn and wheat producer, has had cotton in his rotation more than six years. Like many growers in the northern Texas Panhandle region, he added the fiber crop after seeing dwindling groundwater sources and higher pumping costs due to escalated energy prices. What he gained was a high-producing, high-quality crop and better corn yields to boot.
He had more corn for 2007, due to higher prices, but still likes how it benefits his cotton.
“We really like this rotation,” says Friemel, whose crops are grown under a strip-till system and center pivot irrigation, including some half-mile pivots. “We flip the crops every year. Before, with continuous corn, we were running short on water, faced rootworm problems and other situations that wouldn't allow us to maintain a 180-200-bu. yield needed to make irrigated corn work here. We were seeing only 160 bu.”
By adding cotton to the rotation, his corn yields are back up to 200 bu., thanks to a clean field following cotton. And his cotton averages 2-2½ bales/acre (900-1,100 lbs.), and some acres were expected to yield three bales for 2006.
“The corn really helps our cotton production,” says Friemel. “The cotton uses the nutrients and moisture left behind in the profile. There is usually 3-4 ft. of moisture in the profile following corn.
Friemel grows Roundup Ready (RR) cotton and was mostly 100% RR Flex in 2007. His corn has been about 25% RR, but he plans for none in 2007. “We'll have zero RR corn this year,” he says. “There is just too much volunteer corn that comes up in the RR cotton. It's too expensive to control it.”
About 25% of his cotton is Bt, while about 60% of the corn has Bt characteristics.
“We really don't have much of a bollworm problem,” says Friemel, “but if one occurs, we want to be able to get everything sprayed that needs it. Having a portion of the crop in Bt cotton means we have less insecticide to apply and helps us manage such problems.”
The RR cotton helps prevent a grassy weed buildup leading into the next corn crop. “That's a real plus for corn behind cotton,” he says.
The value of rotation is also high in the Midsouth, where Steve Martin, Mississippi State Extension economist, says a solid cotton/corn rotation is certainly no joking matter.
Martin says cotton rotated with corn every third crop will yield 8-15% more than continuous cotton.
For typical 600-800-lbs./acre dryland continuous cotton, that adds an extra 120 lbs. with a 15% yield increase. For the 1,000-1,100-lb. irrigated crop, that's up to 165 lbs. more.
Better yields are also seen for soybeans or rice rotated with cotton.
“Rotations depend on the soil type,” says Martin. “In our sandier soils, corn and cotton or milo and cotton are preferred. In our heavier clay soils, a corn rotation with rice or soybeans perform best. People who don't grow rice usually stick with a Midwestern-type rotation of corn and soybeans.”
Martin notes that higher corn prices will likely bring more cotton rotated with corn.
Alabama studies of cotton rotation patterns are nothing new at Auburn University. In fact, the “Old Rotation” study, conducted continually since 1896, is the oldest continuous cotton experiment in the world, and the third oldest field crop experiment on the same site in the U.S. It's included in the National Register of Historical Places.
Its long-time experiments explore the value of rotating cotton with other crops with or without a regional nitrogen-restoring winter legume, crimson clover,in the system.
In a recent study, continuous cotton planted with no legume yielded about 400 lbs./acre. But cotton rotated after corn and the winter legume yielded about 1,000 lbs. The addition of 120 lbs. of nitrogen (N) in the study bumped yields to 1,140 lbs.
Corn yields were also increased with the additional N, up from 109 bu./acre to 136, and 123 bu. over a three-year period. When rotated with soybeans, cotton yields were similar to those from the corn rotation. Beans had a three-year average yield of 47 bu./acre.
In a Cotton Incorporated study in conjunction with the University of Missouri, yield response to N was evaluated in cotton-corn and cotton-soybean rotations. There were positive yield benefits from both.
Cotton Incorporated says plots following soybeans with 0-25-lb.-N/acre applications had greater percentage yield increases than cotton with the same rates following corn or cotton. But the optimum N rate after each crop was still in the 75-100-lb.-N/acre range.
Crop rotation helps to manage nematodes and diseases. And crop rotation can be a significant component of a weed management program, say University of Georgia weed scientists. Good cotton production requires better weed control than either corn or soybeans.
Crop rotation enables growers to use different herbicides on the same field in different years. Georgia scientists say growers can reduce or prevent the buildup of problem weeds by rotating cotton with other crops and selecting an herbicide program for the rotational crop that effectively controls weeds difficult to control in cotton.
Overall weed population should be lower. Crop rotation and properly planned herbicide rotation can also help avoid herbicide-resistant weeds.
When selecting an herbicide program for crops that will precede cotton, Georgia scientists encourage growers to read the label carefully.
Friemel concludes that overall, his cotton-corn rotation more than complements each crop. “I've heard it called a ‘euphoric’ rotation,” he says. “I'm not sure about that. But I do think cotton behind corn is all positive.”