April 16, 2012
Cotton acreage has rebounded in Alabama in recent years, but it’s anyone’s guess as to where it may go this year, especially considering the competition from other crops such as corn, soybeans and peanuts.
Looking at current commodity prices, the state’s farmers have some difficult decisions to make, says Dale Monks, Auburn University Extension cotton agronomist.
“We had about 200,000 acres in 2009, 350,000 acres in 2010, and 460,000 last year, but I don’t have a good number for this year. My opinion has been that it’ll go up, but I’m not certain,” he says.
The state yield was 762 pounds per acre in 2011. “Basically, this tells me we had some tremendous yields out there, but we also had areas that suffered through severe drought. Anytime Alabama’s average yield gets over 700 pounds per acre, that means we have some tremendous cotton out there,” says Monks.
Staple, micronaire, strength and uniformity looked good, for the most part in 2011, he says.
“If you look at our cotton compared to some other states, our mic was in a better range than some.”
Whether or not growers were located in the path of rainfall patterns meant all the difference last year, says Monks. “Rainfall patterns really were the make-it or break-it for the crop last year. There were about three big storms that came through in late July or early August. That band of showers, from east to west, is what made the crop in central Alabama. If you were just outside those bands, your crop might have been half of the ones inside the bands.”
With dry conditions in the state last year, it was a late crop from the beginning, he adds.
“But because of the heat and dry weather during the summer, the maturity rate increased, and the crop caught up with itself by the end of the season. Some growers in Alabama made as good a crop as they’ve made in years, while others made very poor yields.”
It’s expected that growers will be comparing commodity prices up until planting time.
“Will prices continue to hold up, and how will it compare to other crop choices?” asks Monks.
“Corn and soybeans are competing with cotton in north Alabama’s Tennessee Valley. With peanuts, we’re not really into crop rotations in some areas — six years in and one year out isn’t a rotation. We’re just hoping that something bad doesn’t happen next year in peanuts. We’ve seen some good prices on peanuts, to the point to where they were competing with other crops.”
As far as cotton variety selection, growers need to look at all the data, including OVT’s, on-farm data, and information from the various companies. Local and regional experience with a variety also should be a guide, says Monks.
Everyone has own process
“Some people plant what others tell them to plant, and others plant based on the data and what others are telling them. Everyone has their own process of deciding what to plant, and all we can do is present the numbers to you.
“If you can’t have multiple years of data, then the next best thing is to have multiple locations within the same year. At least you’re comparing similar environments over different soil textures.”
Researchers and Extension specialists in Alabama continue to evaluate conventional cotton varieties, says Monks, and it’s expected there will be some options from public breeders available to growers this year.
Assessing the major cotton pests in Alabama cotton, Monks lists the usual suspects — gylphosate-resistant Palmer amaranth pigweed and stink bugs — and a relatively new threat, corynespora leaf spot.
In contrast to most other field crops, leaf spot and blight diseases have never impacted cotton yield. And leaf spots such as stemphylium, cercospora and alternaria — which are fairly common on cotton grown on lighter Coastal Plain soils — are typically associated with a potassium deficiency, says Monks.
“If it’s a leafspot, we usually say it’s due to low potash on the plant, and that’s the right diagnosis for a lot of these problems. The thing about the corynespora is that the target shape of the spot is really not connected to a fertility problem. It is a true leaf spot, where the plant starts shedding leaves, causing yields to go down.”
Corynespora leaf spot has damaged cotton in southwest Georgia for the past four to five years. With early disease onset, yield losses of 100 to 200 pound per acre have been noted. This past summer, it was found on cotton from the Florida Panhandle up the Tennessee Valley.
Researchers have found that leaf spotting and early leaf shed were heavier in no-till or strip-till cotton, in fields where cotton followed cotton. Frequent showers and/or irrigation, along with high nitrogen fertility levels, also may have contributed to increased disease.
Individual leaf spots have a distinct “zonate” or “target spot” pattern with alternating laight and dark brown bands.
Limited information concerning factors that influence the onset and severity of corynespora leaf spot in cotton complicates the development of effective control strategies.
In fields where significant disease was seen in 2011, cropping corn, peanuts, soybeans or summer grazing should reduce the carryover of inocula.
If rotation isn’t an option, high-risk fields should be deep turned to bury residue from the previous cotton crop and then planted to a less susceptible cotton variety.
For cotton following peanuts or corn, tillage likely will have little or no impact on disease development. In irrigated cotton, growers should water according to crop needs to avoid creating the wet environment that would favor rapid disease spread.
Fungicides have been used with some success to prevent corynespora leaf spot-relate premature defoliation, but their value in protecting cotton yields has been difficult to define.
“In most cases, the fungicide needs to be applied before the disease gets on the plant, which is difficult to do,” says Monks.
Quadris, Headline and Twinline are all labeled for leaf spot diseases on cotton.
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