Weather Continues to Dominates the Start of the 2019 Cotton Season, Wet Conditions Delay PlantingThu, 09 May 2019 11:50:37 CDT
The weather still dominates the start of the 2019 cotton season. Cooler than normal and saturated fields has prevented the start of planting this year. Dr. Mile Karner in the early 1990’s once said at end of May “Best looking cotton is still in the bag.” Hopefully the weather will start cooperating. As the following state maps show planting conditions are not ideal nor will be until next week. Every field needs to be evaluate at time of planting to ensure that good emergence occurs. This is critical because of seed availability and the shorter planting window replanting may not be an option. (Graphs, charts and tables with additional information included in the original version of this article can be accessed by clicking here to jump to the original story).
Cool wet condition has delayed planting, the following is an excerpt from Cotton Comments Volume 9 edition 1 April 10, 2019. This is usually a late April or early May issue not mid-May.
The optimum temperature for cotton germination is near 85 degrees F°. Cooler temperatures can lead to poor stands or stand failures if the correct conditions align. Under cool temperatures the physiological processes involved in germination can be very slow which can in turn result in slow growth and perhaps increased susceptibility to various seedling disease pathogens.
It is suggested that planting be delayed until 1) mid-morning temperatures in the rooting zone exceed 60 degrees F° at a 6-inch planting depth, and 68 degrees F° at the 2-inch depth; 2) the five-day forecast indicates dry conditions and at least 25 DD60 heat units; and 3) the five-day forecast projects low temperatures above 50 degrees F°.
The standard calculation for cotton DD60 heat units is: ((maximum air temperature, F° + minimum air temperature, F°) / 2) - 60 = DD60 heat units.
Essentially, the average air temperature for the day is determined and the 60 degree F° developmental threshold for cotton is subtracted. The DD60s for each day are then totaled. If one has faith in the local forecast, then the projected high and low for the following several days can be used to calculate DD60s.
Planting conditions for rapid germination and emergence include:
1) high quality seed with good to excellent Cool Germination Test data (>60%)
2) a favorable 5-day forecast
3) minimum air temperature of at least 50 degrees Fº, and maximum air
temperature of at least 80 degrees
4) plant into a firm, moist seedbed about 1 inch deep but not more than 2 inches
Source - OSU S.W. Research & Extension Center
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