Shane Osborne, who will handle Oklahoma cotton issues following retirement of long-time Oklahoma State University cotton specialist J.C. Banks, says cotton has begun to recover from a slow start.
"Most cotton planted prior to May 15 in Southwest Oklahoma is close to or has reached the pinhead square stage, which is a welcome sight due to its slow start,” Osborne says.
"As usual, a crystal ball would have helped many of us wait until mid-May to plant; however, fears of fleeting moisture trumped the lack of ideal temperatures leading to a substantial numbers of acres being planted the first week of May. It is amazing how a few night time temperatures below 50 degrees can make a two-week old stand of cotton look six days old.
Osborne says farmers were reminded of how valuable warm weather is to a healthy vigorous stand of cotton. “Fortunately, we won’t see 40-something degree nights again until harvest. Since May 20 we have had some ‘cotton weather’ and most fields have kicked into high gear. The first 10 days of June have been somewhere between 95 and 103 degrees.
He says three issues come to mind with cotton growing well: "Fleahopper control, plant growth regulators and irrigation timing.
He focuses on plant growth regulators and irrigation timing.
“The earliest recommended application of a PGR should not occur until matchhead square stage, about seven to 10 days after pinhead square, and only if you expect soil moisture conditions to remain favorable for the next 10 days” he says. “If soil moisture is insufficient, there will be no need for a growth regulator.
“Typically, we don't depend on a yield increase from use of a plant growth regulator; however, PGR's do promote earliness and often earliness pays in the fall. Since there are multiple products and rates to choose from I recommend calling or coming by our office to discuss PGR questions.
"That brings us to irrigation. If you have the ability to irrigate, consider some key things to keep in mind on when to start. First, we should dispel the myth about stressing cotton to help it flower. Nothing could be farther from the truth or more counter-productive.”
Osborne says stressed cotton will flower earlier. “But it is more important to understand that cotton's yield potential quickly spirals downward when flowering is initiated by stress rather than natural development. So what does that mean for scheduling irrigation, or the value of timely rainfall in dryland production?
"The key is to understand when yield potential is developed. Although cotton's greatest demand for water occurs at peak bloom, development of yield potential occurs much earlier. We need to understand the relationship between the number of nodes above white flower (NAWF) at first bloom and cotton's overall yield potential.
He says the number of nodes above white flower is greatest at first bloom and begins to decrease shortly thereafter. “Since each node on the plant represents a fruiting branch, any management practice that limits the number of NAWF above our first white flower essentially limits yield potential.”
Osborne says August in southwest Oklahoma is the latest farmers can expect a bloom to develop into a productive boll. “When cotton experiences significant moisture stress between the pinhead square and bloom stages, the NAWF will always be less than optimum at first bloom, resulting in a reduced number of fruiting branches and overall yield potential.”
He says NAWF at first bloom should be in a healthy range (7to 8). At less than six, yield potential is reduced.
"Since we know it takes approximately 21 to 25 days for a cotton plant in pinhead square stage to reach bloom, our timeline has been established,” Osborne says. “Once the plant reaches bloom the yield potential has already been set. Therefore, it is critical to maintain good soil moisture within this important three week period to protect yield potential.”
He says if cotton is at the pinhead square stage and soil moisture conditions become poor within seven to 10 days, growers should be prepared to irrigate, even if they have a limited supply of water.
“To discuss any of these topics, feel free to call or come by the office," Osborne says.
Osborne works at the OSU Southwest Research and Extension Center south of Altus, Okla., on HW 283. The office telephone number is 580-482-2120. Osborne's cell telephone number is 580-471-7815.
TALKIN' COTTON is produced by North Texas, Oklahoma and Kansas Cotton, the cotton industry, which supports and encourages the production of cotton in the Rolling Plains of North Texas, Oklahoma and Kansas. For more information on the cotton scene, see ntokcotton.org and okiecotton.org. For comments or questions on Talkin' Cotton, contact firstname.lastname@example.org.