What is in this article?:
- It's never too early to start considering the factors that dictate the use of plant growth regulators in cotton.
- Past research has shown that there's no interaction between plant growth regulator and nitrogen application strategies on yield and fiber quality.
KNOWING THE AGGRESSIVENESS of your cotton variety and environmental conditions during the production season are important in making plant growth regulator application decisions.
Though it’s early in the cotton growing season, the factors to be considered when deciding when and how much plant growth regulator to apply are already at play in many fields.
Past research has shown that there’s no interaction between plant growth regulator and nitrogen application strategies on yield and fiber quality, says Dale Monks, Alabama Cooperative Extension System cotton specialist.
“Those are two separate issues, but you’ve got to consider the variety you’re growing, and you’ve got to know your nitrogen status before you can begin your PGR application. If we wait until first bloom before we decide how we’re going to manage that plant, it’s too late if it’s an aggressively growing plant. It’s hard to slow down,” says Monks.
But in parts of the Cotton Belt, some growers are putting extremely high rates of PGR on taller, aggressive cotton varieties, he says. “You have to start early, and the nitrogen level of the crop does come into play. But it’s not a good idea to attempt to control plant height with nitrogen. Put out nitrogen for yield, and then deal with plant height based on the variety and conditions. Look at the status of the plant and how it’s growing,” says Monks.
Plant growth regulators include traditional mepiquat or mepiquat chloride products. “Whenever you use a generic product in an effort to save money, check the formulation. Is the formulation 4 pounds per gallon or 2 pounds per gallon? It my be cheaper, but then you have to use twice as much. Some generics are not formulated quite the same,” he says.
Most growers, says Monks, know where they will have problems with rank cotton, and they try to control it.
The amount of nitrogen applied to cotton certainly is a factor, he adds. “The problem last year is that we had a lot of sidedress applications that went out really late. We just couldn’t get into the field. In the Wiregrass region of Alabama, it was rainy and cloudy for 59 days straight, and we all know that cotton responds to sunlight.
“And it’s not just daylight – it’s the quality of sunlight that we’re looking for. Last year, we ended up not being able to get into the fields, and some of those nitrogen applications went out late. Where some went out early, we weren’t sure what was left after all the rainfall. When you’ve had water standing for a few days, do you assume it’s all gone? Do you put out the full load again or part of it?”
Monks notes that even in a year of excessive rainfall in areas, Alabama growers still made good state yield average in 2013 of about 820 pounds.
“We’re in an era now where the new cotton varieties are in the ‘elite’ level. In Alabama, if we get the rainfall, it’ll take our yields up. If we have had the rainfall with clear skies in 2014, we could easily hit over 2 bale/acre yields, just like in 2013.”