Nearly four weeks of torrential downpours are thwarting the yield potential this year's cotton had just a short time ago. Because of adverse weather conditions, preventing further yield and quality losses during harvest and ginning is critical.
“Recent rains have caused farmers to suffer both quality and quality losses of their cotton crop,” says Tommy Valco, cotton technology transfer and education coordinator for USDA's Agricultural Research Service in Stoneville, Miss.
“Cooler temperatures and low humidity should help mitigate current crop conditions somewhat,” says Will McCarty, Extension cotton specialist at Mississippi State University in Starkville, Miss. “Weather has not only affected cotton lint and seeds but has stimulated tremendous re-growth in all fields. Most cotton defoliated before the rains will most likely need some type treatment before picking.”
Valco says, “Cotton growers should wait for complete drying of the fiber and seed before harvesting. It may take seven to 10 days of good drying weather to get to that point, but waiting will help to improve the fiber's color grade by bleaching out the gray color,” says Valco.
These “drying” days, should have low to moderate relative humidity levels, moderate to high temperatures, and lots of sunlight, according to Stanley Anthony, supervisory agricultural engineer and research leader of the USDA Cotton Ginning Lab in Stoneville.
“In most instances, if at least 50 percent of the cottonseed are firm, cotton can be ginned. Adequate sunshine may possibly move the color of the cotton from the current light spot or spotted to white.”
Valco says, “If cotton is harvested while it's still damp, and seed moisture levels are high, that cotton must be ginned with 24 to 48 hours of harvest. In addition, storage will be more difficult, and extra lint cleaners may be needed during the ginning process.”
McCarty suggests growers consider the necessity of having the seed-cotton as dry as possible before moduling and ginning. An application of one of the phosphate materials (Def/Folex) plus paraquat (Gramoxone Max/Boa etc.) or sodium chlorate plus paraquat may be good second treatments for this situation, he says.
For first applications, McCarty says, hormone-type defoliants will generally do a better job removing the young tender regrowth and inhibiting regrowth. For that purpose, he suggests a tank mix of Dropp/FreeFall plus ethepon (Prep, Super Boll etc.) or Dropp/Freefall plus Finish or Cotton Quick. In some situations, a three-way combination of Dropp/FreeFall plus Harvade plus ethepon (Prep/Super Boll etc.) or Leafless (a prepack of Dropp plus Harvade) plus ethephon may be a consideration.
“In most all cases, these primary treatments will need to be followed by applications as stated above. Rates of selected materials should be based on field and weather conditions. The materials and combinations listed are only examples and there are numerous materials and/or combinations that will perform adequately in various respective situations,” McCarty says.
Where weeds top cotton, McCarty suggests that the cotton be defoliated first with materials that will retard re-growth and the weeds be attacked in a follow-up application. “Combinations of defoliants and desiccants in an initial or primary application may lead to excessive leaf sticking and reduce already deteriorated grades.”
If open cotton bolls are harvested too quickly after being exposed to excessive moisture, Anthony says, seed cotton moisture will often be above 12 percent, and the seed cotton cannot be stored either in trailers or modules for more than 24 hours. Module temperatures must be monitored in at least six locations immediately after module formation and every 12 hours afterward for at least six days.
According to McCarty, module temperatures must be monitored in at least six locations immediately after module formation and every 12 hours afterward for at least six days. If temperatures rise more than 20 degrees or reach 120 degrees, gin immediately.
Relatively impermeable polyethylene bagging for bale covers may be a potential problem since excess moisture may be in the cotton.
When ginning any cottonseed that germinated as a result of the recent rains, Stanley says substantial drying may be required to ensure that the gin stand remains operational. In addition, two stages of lint cleaning will likely be required, and if air-type lint cleaners are used, care must be exercised to ensure that substantial quantities of fiber which is attached to the seed coat is not removed. It may be necessary to close the opening in the air jet cleaner to reduce or prevent excessive fiber loss.
“Last year, seed cotton harvested early (Sept. 4, 2001) produced about 85 percent as much cottonseed as expected because of the germinated cottonseed component, and those cottonseed graded 75 instead of the usual 100. Thus, cottonseed value may be about 65 percent of normal,” Anthony says.”