An oncoming cold wave originating in the Arctic regions has Southern Plains wheat growers concerned about possible damage. Concern is heightened because the 2020 winter wheat crop is ahead of schedule in its developing after exiting dormancy. In fact, some key areas of Kansas are well into the jointing phase, which is the very start of the formation of the new wheat head for the upcoming harvest. Comments on social media during Saturday, April 11, pointed that out.
"We had a Kansas Wheat board call yesterday (Friday, April 10), varying conditions across the state," noted Kansas Wheat Growers CEO Justin Gilpin replying to a DTN Twitter question. "Reports of central Kansas 80-90% jointed and most vulnerable. Quote on #Wheat around Salina Wednesday with 80-plus temps, 'Head was 4 inches above ground. It's moving fast now,'" Gilpin said.
An information article from Kansas State University points out that wheat "... rapidly loses hardiness during spring growth and is easily injured by late freezes." In the jointing phase, temperatures at 24 degrees Fahrenheit (minus 4.4 Celsius) for two hours cause moderate to severe damage according to the KSU document. But the temperature damage threshold rises to a value of only 28 deg F (minus 2.2 C) when wheat is fully jointed.
Central Kansas typically has the highest winter wheat yields in the state. This area has overnight low temperatures Sunday night, April 12, into Monday, April 13, forecast in the range of 23 to 27 F (minus 5.0 to minus 2.8 C). This is in the range at where the 80 to 90% of the central Kansas wheat crop that is jointing could be damaged.
The Kansas State document on freeze damage to winter wheat is at this link: https://www.sunflower.k-state.edu/….
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