Cotton Emergence, Heat Units, and an Ag Symposium

Howdy!

  This season has been off to a good start, I've been in the field planting a few variety trials and gearing up for this year. I know some folks were planting as early as the first week of March, and others are still planting now. The rain over the weekend was good for a lot of folks, and I hope the weather cooperates with us this season.

  Cotton growth is strongly influenced by temperature, and germination occurs quickest in warm (above 64 degrees Fahrenheit), moist soils with a high oxygen content. Seeds are in a state of suspended animation due to a lack of water and oxygen. Germination begins when the seed tissue absorbs water, activates metabolism and initiates growth. Inside the seed, the cotton embryo has a radicle at one end and a plumule at the other. The plumule will form the stem and leaves, while the radicle will form the roots. Temperatures below 50°F can kill the radical in the soil once the seed has begun to germinate. Cotton plants require more than 100 hours above 64°F to emerge. Germination can begin when the daily temperature is 60°F at the seedling's depth, but growth will be slow. Cotton needs about 50 heat units to reach emergence.

  Heat units (DD60s)are an estimation of the accumulated temperature effect during a day based on the average of the maximum and minimum daily temperatures in degrees Fahrenheit.

             (°Fmax + °Fmin)

DD60=                 2              - 60

  I calculated the heat units for this past week (Sunday to Friday) using online recorded high and low temperature information:

Wharton: 8.5; 15.5; 15; 4; 4; 8.5
Total for the last 6 days= 55.5

Bay City: 10.5; 16; 16.5; 5.5; 6.5; 14.5
Total for the last 6 days= 69.5

Edna: 12.5; 17.5; 14.5; 6; 5.5; 12.5

Total for the last 6 days= 68.5

  Emergence has been a little spotty in places with the cooler nighttime temperatures we've had. If you are worried about stand in a field, plant populations from 13,000 to 26,000 plants per acre with some spacing uniformity are considered viable stands.

  Below I have included a flyer for our upcoming Ag Symposium. This will be taking place in Wharton, Jackson, and Matagorda counties. Contact your local extension office to find out more for each location and to RSVP.

Feel free to contact me if you have any questions or comments, and have a great weekend!

Sincerely,

Kate

Sources:

http://cotton.tamu.edu/General%20Production/Georgia%20Cotton%20Growth%20and%20Development%20B1252-1.pdf

http://cotton.tamu.edu/General%20Production/scs-2005-17%20Soil%20Temp.pdf

https://cals.arizona.edu/crop/cotton/cropmgt/population_evaluation.html

Weather information from Weather Underground's Calendar

For more information check out:

Cotton Growth and Development overview

Cotton Growth and Development

Replant Decision Making

Soil Temperatures for Cotton Planting