Oklahoma’s Cotton Crop in Need of Additional Heat Units to Finish Out the Year, After a Cool August

The 2017 cotton crop maturity rate has taken a bit of a hit with the cooler August temperatures, according to recent observations noted in the weekly Cotton Comments newsletter, distrubted by OSU Extension. The month of August closed out at about 19 percent below normal for cotton heat unit accumulation. Nearly all of the daily high temperatures were below normal. Daily low temperatures were normal for most of the month, until the last few days.

Looking back at the same temperature data for August, 2016, the bottom line was that it finished about 10 percent below normal for cotton heat unit accumulation. However, the months of September and October of 2016 provided 444 and 242 cotton heat units, respectively. The long term averages for those months are 427 and 87, respectively. In spite of the 10 percent below normal August in 2016, farmers still managed to finish up that crop very well. One big question remains – what will happen this year?

The Mesonet reported heat unit accumulations for planting dates of May 10 and 20, and June 1, 10 and 20 through August 30 for various locations in the southwestern corner of the state. The total for the various planting dates at Altus range from 2138 for the May10 date to 1500 for the June 20 date. The “normal” or what may be called the “long-term average” (from 1981 through 2010) from August 31st until October 22 (the time cotton heat units approach zero) totals 514. Theoretically, at least there is quite a bit of cotton maturing temperatures still to come. Generally speaking one 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, or late set bolls are a large fraction of the total production, this may be inadequate for good boll maturity. A lot of things can impact cotton maturity besides just heat units (solar radiation, late season rainfall, etc). However, based on the available information, 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 we have a “normal” September and October. If you shift this to areas farther north and September and October fail to deliver outstanding maturity temperatures, some high yielding dryland fields may have a challenge to mature. It appears that the irrigated fields which were planted before the end of May are probably going to finish okay.

Source: www.oklahomafarmreport.com