Necessary Heat Unit Accumulation for Cotton Maturity Continues to Lag Behind into SeptemberTue, 12 Sep 2017 12:08:44 CDT
In the latest Cotton Comments newsletter published by the OSU Southwest Oklahoma Research and Extension Center, cooler than normal temperatures are reported to have been encountered during the first 11 days of September. The first 11 days of September generated about 136 cotton DD60 heat units compared to 199 for the 30-year normal (1981-2010).
Overall, temperatures have been recorded below normal for the last 40 days or so, compared to Oklahoma’s 30-year average. With warm weather being forecasted, though, cotton farmers can hope the remainder of the season will continue with good to excellent weather that will enhance maturity for late planted fields.
The total heat unit accumulations for the various planting dates at Altus range from 2275 for the May 10 date to 1637 for the June 20 date. The “normal” or the “long-term average” (from 1981 through 2010) from September 11th until October 22 (the time cotton heat units approach zero) totals 332.
Theoretically, there is still quite a bit of cotton maturing temperatures still to come.
“Generally speaking,” contributing author and research director Randy Boman writes, “we can still have fairly good maturity in cotton crops with the lower yields typically encountered in dryland production when the heat units total out to 2000 or so. If really high yields are present, or if late set bolls are a large fraction of the total production, this may be inadequate for good boll maturity.”
However, he cautions that a lot of things can impact cotton maturity besides just heat units, such as solar radiation, late season rainfall, etc. Based on the available information, though, it appears that dryland cotton planted as late as June 20th around Altus that has up to 2 bale/acre potential may still be okay, assuming a “normal” September and October transpires.
Farther North, if September and October fail to deliver outstanding maturity temperatures, some high yielding dryland fields may have a challenge to mature. But, it appears that irrigated fields which were planted before the end of May are probably going to finish okay.
“These are only my thoughts and as usual, only time will tell,” Boman disclaimed. “We need to recognize that we didn’t have any ‘maturity busting’ temperatures (low temperatures less than 40 degrees or so) until after October in 2016, perhaps we can dodge that bullet again in 2017.”
Take a look at this week’s Cotton Comments newsletter, to view graphs illustrating the above information, by clicking or tapping here.
Source - OSU Southwest Oklahoma Research and Extension Center
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