PCG EMAIL SERVICES: Timely planting tips for the Texas Northern Plains
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Wed Apr 29 12:03:01 CDT 2015
Timely planting tips for the Texas Northern Plains
by Ken E. Legé, Ph.D.
With warmer-than-average temperatures and generally very good soil moisture across the high and rolling plains in April, many growers have thought about some early plantings of cotton to get a jump on the season. While conditions appear to be very good for those early plantings, it is always a good idea to analyze the forecast carefully and check the trends in soil temperatures in your area.
There is always a great tendency to rely on the calendar for field activities, but in reality, the cotton plant doesn't own a calendar; instead cotton plants rely on temperature and moisture. We are very fortunate in West Texas and Oklahoma to have the West Texas Mesonet and Oklahoma Mesonet to provide us with up-to-the minute air and soil temperatures for numerous locations across the high and rolling plains.
The first step, and perhaps one of the most important steps a grower takes all season, is to establish a uniform stand of cotton. Having a uniform stand is even more important than the seeding rate in many cases. Beyond choosing the right variety that has good early season vigor and knowing the warm and cool germination of the seed lot you've purchased, studying the weather forecast is key to obtaining a good, consistent stand of cotton.
General guidelines for forecasted temperatures are based on cotton heat units, or DD60s; to calculate, add the high and low temperature for a 24-hour period, divide by 2, then subtract 60. When considering when to plant, the heat unit accumulation for the next 5 days should be at least 16 heat units for adequate conditions; planting conditions are very good if the next 5 days' heat unit accumulation is between 25 and 50, while 5-day heat unit totals that exceed 50 translate to excellent predicted conditions for planting cotton.
As of April 23 in Lubbock, 5-day heat unit totals are in the very good range and soil temperatures have persisted in the mid-60s range; however, the forecast shows a good chance of rainfall on Monday, April 29 and Tuesday, April 30, which will also bring some cooler temperatures. In fact, the low temperatures are forecasted to be in the upper 40s on those days. Cottonseed that are imbibing moisture during germination are particularly vulnerable to cold and chilling injury. Seed subjected to 50 degrees F during imbibition can be severely affected, while those subjected to 41 degrees F during imbibition may not germinate. Accordingly, it is recommended that planting be delayed until that period of cool, wet conditions passes, at which time the forecast and soil temperatures can be re-evaluated.
At Tulia on April 23, the 5-day heat unit total is in the adequate range, but soil temperatures have persisted in the upper 50s. Similar to the Lubbock area, it is advised growers delay planting of cotton until May 1, should the cool front bringing a good chance of rain and cool temperatures does occur. A rapid warm up is forecasted; coupled with the potential additional soil moisture the cool front may bring may drastically improve planting conditions at that time. Growers should continually evaluate air and soil temperatures and the 5-day forecast to make the best possible planting time decision.
Some growers may still find it necessary to plant now due to their own operations' planting logistics, which is understandable. Each individual operation is unique and must weigh the risks and benefits of performing field activities. Just make an informed decision and be prepared to evaluate the stand.
Growers should also keep in mind that rarely does early planting equate to early harvest. In general, those early-planted stands tend to struggle with cool temperatures, early insect infestations, or sandblasting, and end up maturing, at times, at the same time or later than fields planted a week or more after those first planted fields.
For 2015, also note that with the winter and spring moisture many areas have experienced could potentially bring higher numbers of Thrips from the higher numbers of weeds in field borders and bar ditches. These early-season insects could further delay your cotton crop, or at worse, destroy an otherwise uniform stand of cotton that you've worked hard to produce.
Ken E. Legé, Ph.D.
PhytoGen Cotton Development Specialist, Lubbock, TX
806-773-7310; kelege at dow.com
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