Determining when to apply harvest aid materials to cotton has sometimes been described as more art than science. It may not be as straight forward as herbicide application or as certain as spraying a tried and true insecticide to control a specific target pest.
Not to suggest that either of those tasks is without challenge, but timing harvest aids comes with a few more uncertainties. Crop maturity, weather at application time and for the next few days, and product selection all play important roles in harvest aid success.
Texas AgriLife scientists have a few guidelines to improve the odds.
Mark Kelley, Extension agronomist, cotton; Wayne keeling, systems agronomist, AgriLife research; and Gaylon Morgan, state Extension cotton specialist, have developed a harvest aid guide for the Texas High Plains and Rolling Plains.
They agree that: “Proper use of harvest aids can result in earlier harvest, preservation of fiber quality, and fewer seed quality reductions due to field exposure.”
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It’s especially important in the High Plains where weather can play havoc with mature cotton and can “result in considerable reduction in lint yield and fiber quality,” as well as significant lost dollar value of the crop. Open boll picker-type cotton varieties as well as stripper cotton that are less storm proof are even more vulnerable to weather damage.
Harvest-aid chemicals reduce the risk.
Applying those materials at the proper time may be complicated but is critical.
“Premature harvest-aid applications can result in loss of lint and seed yield and reduced fiber quality, which ultimately can result in reduced profits or greater economic losses,” according to the harvest aid guide. “Correct timing of harvest-aid applications can enable producers to obtain optimum yields of high quality lint and seed.”
Even when application is made at the proper time, unexpected problems can occur to put the crop at risk.
“Even when applications are made under ideal conditions, inclement weather or lack of available machinery and/or labor can delay harvest for several days or longer. Delayed harvest timing can have adverse effects on both yield and quality of lint and seed.”
Specialists say Texas High Plains cotton growers face difficult decisions at harvest time “that have profound impact on yield and quality.”
Data from a comprehensive 3-year project (2000-2002) that addressed the fundamental data requirements of stripper harvested cotton in the Texas High Plains near Lubbock offers guidance. The field was planted to a storm-proof variety, Paymaster 2326RR, and the trial included harvest-aid chemical termination with varied harvest dates. Lint yields were reduced with later harvest dates one out of three years. Also, high volume instrumentation (HVI) analyses indicated significant reductions in fiber quality when harvest was delayed. Biggest losses came from length, strength and color grades. Those reductions resulted in lower lint loan values and lower net values per acre.
Planting-seed quality also suffered with later harvest dates and germination percentages were lower in two out of three years. “This is an important consideration for individuals producing planting-seed for companies or for those that retain seed for planting next year's crop.”
Even with a storm-proof variety, the tests show that significant reductions in lint yield, HVI fiber quality, economic returns, and seed quality can occur if harvest is delayed. “Greater losses may be incurred with delayed harvest if a variety with a lesser degree of storm resistance is produced.”
Timely harvest aid applications and timely harvest improve opportunities for yield and fiber quality and greater net returns.
Click here  for the complete 2013 High Plains and Northern Rolling Plains Cotton Harvest-Aid Guide.