An effective burndown program doesn’t happen by chance. It takes planning and preparation, not just at the beginning, but for what herbicide products will be used the whole season and also what was used on the last crop and next. Doing it right is worth the effort.
From the outset, a cotton crop can be affected by weeds, even to the point of hampering seed germination.
“In some severely weedy conditions, good soil-to-seed contact can’t be achieved, and seed germination suffers,” says Derek Scroggs, LSU AgCenter weed science research associate. “To ensure good soil-to-seed contact, a clean field and planting row are preferred for optimum germination.”
As the drought situation continues across the Southeast, another important reason for starting the season with a clean field is to preserve what moisture there is for the crop itself.
“It is important that the stored soil water and the water from rainfall that does occur be available to the crop and not be transpired by weeds, especially in seasons when rainfall is marginal,” says Phil Bauer, research agronomist for USDA-ARS in Florence, S.C.
“Similarly, winter weeds also compete with the young seedlings for nutrients and sunlight,” he says. “Starting with a clean field allows for better seedling growth by eliminating weeds that will shade the seedlings and take water and nutrients from the young cotton plants.”
Weed And Insect Control
Starting with a clean field generally means giving the crop a jump start on weed competition.
“A clean field allows a plant to germinate in the absence of weeds and utilize all of the factors that compete for sunlight, water, nutrients and space,” says Scroggs.
An effective burndown program allows producers the ability to control difficult weeds early before they are allowed to grow too large.
“An early burndown application of small weed seedlings should be considered when weeds like cutleaf evening primrose and wild radish are present because these weeds are more difficult to control when they are bigger and the cotton is established,” says Bauer.
Scroggs also says that destroying vegetation early helps with early season insect pressure.
“For example, cutworms over-winter on hosts such as henbit,” he says. “If a grower can control henbit and other winter weeds early enough before planting, then a reduction in cutworm numbers can be observed.”
Keys To Effectiveness
As with every production practice, timing is an important part of the burndown process.
“Two key factors are knowing the weed species that need to be controlled and the application timing of the burndown herbicide,” says Bauer. “Timing is important, especially if a cover crop was planted in the fall or if there is a heavy stand of winter weeds. In these cases, burndown applications should be made two to three weeks before cotton planting to keep the winter plants from depleting soil moisture.”
Producers should choose a herbicide or combination of herbicides that will control the most troublesome and abundant weeds that are present in a particular field, says Scroggs, who works at the Dean Lee Research Station in Alexandria, La.
As with any pesticide application, Scroggs says producers should always read the product labels and be aware of any pre-plant intervals or plant-back restrictions that the herbicide product may contain.
Contact Amanda Huber at (352) 486-7006 or firstname.lastname@example.org.