Plains cotton producers preparing for harvest have an updated harvest-aid guide available to help them make the most of this year's delayed crop, said a Texas Cooperative Extension agronomist.

"We have updated the High Plains and Northern Rolling Plains Cotton Harvest-Aid Guide," said Dr. Randy Boman, Extension cotton agronomist based at Lubbock. "The guide is available online at http://lubbock.tamu.edu under the 'What's New' heading, and in the Cotton Section of the web site (http://lubbock.tamu.edu/cotton/ ). "Weathering considerably reduces the dollar value of cotton lint unless producers take steps to protect both yield and quality potential. Even in a normal year, producers who use harvest-aids can speed harvest of a mature crop and protect lint quality and yield potential."

To date, 2007 has not been a normal year for Plains cotton producers. Rains at planting and the cool, rainy weather that followed helped defray irrigation costs, but put the crop slightly behind its "normal" pace of growth.

"Many fields are later this year due to later planting dates and a cooler growing season than what we've had for some time," Boman said.

The U.S. Department of Agriculture's Sept. 12 crop report projects this year's Plains cotton crop at 4.5 million bales from more than 3 million harvestable acres in the region. If this holds true, 2007 could supplant 2006 as the third largest crop, Boman said. Even so, producers will need good open weather in September and October to properly finish many fields, he added.

Regardless of weather, there are several factors that affect the usefulness and performance of harvest-aids from season to season, he said.

"Warm, calm, sunny weather increases harvest-aid performance," Boman said. "Soil moisture should be relatively low, but sufficient to maintain active plant growth without moisture stress. Soil nitrogen levels should be relatively low, and plant leaves should be actively growing and uniformly expanded.

"Plants should have little or no secondary growth, a high percentage of open bolls in the cutout stage and they should have shed some mature leaves."

At the other end of the spectrum, these field conditions can reduce the performance of harvest-aid chemicals:

- Application under cloudy skies at temperatures below 60 degrees Fahrenheit.

- Prolonged wet weather following application.

- Plants still in the vegetative stage of growth, with low fruit set.

- Moisture-stressed plants with tough, leathery leaves.

- Rank, dense foliage and delayed maturity caused by high soil moisture and high nitrogen levels.

- And poor spray coverage, incorrect sprayer application or the wrong application rate.

The 2007 harvest-aid guide explains how to determine crop maturity and discusses desiccants, defoliants and boll openers. It also provides tips on selecting and apply these chemicals, late-season insect management, harvesting a treated crop and ways to prevent sticky cotton and other lint contamination.

The guide also includes a treatment table that can help producers select the right treatment or combination of treatments, based on crop maturity, yield potential and expected weather conditions, Boman said.

"We have also received a few calls about how to estimate cotton yield," Boman said. "Estimating cotton yield is a very risky endeavor, but there are two publications available online for those who want to try it.

"Field Estimation of Cotton Yields, takes a fairly simple, user-friendly approach. A more complicated, thorough treatment of yield estimation is available in an older publication by Dr. Will McCarty, former Mississippi State University Extension cotton specialist. Links to both publications are in the Aug. 31 edition of Focus on South Plains Agriculture newsletter."

That newsletter is online at: http://lubbock.tamu.edu/focus/.