Extension notes is written by K-State Extension of Harvey County extension agents Scott Eckert, Susan Jackson and Ryan Flaming. They focus on horticulture and agriculture.
Plenty has been written about concerns over elevated levels of carbon dioxide in the earth's atmosphere, but a Kansas State University researcher has found an upside to the higher CO2 levels. And it's been particularly relevant in light of the drought that overspread the area in recent months.
There was an experiment done at KSU that shows the elevated carbon dioxide that we now have is mitigating the affect the drought has on winter wheat and sorghum and it is allowing more efficient use of water. Between 1958 and 2011, the carbon dioxide concentration has increased from 316 parts per million to 390 ppm.
The research showed that sorghum and winter wheat used water more efficiently as a result of the increased levels of carbon dioxide in the atmosphere, according to K-State agronomy professor Mary Beth Kirkham.
Because elevated carbon dioxide closes stomata (pores on the leaves through which water escapes), less water is used when carbon dioxide levels are elevated. Evapotranspiration is decreased. Due to the increased carbon dioxide concentration in the atmosphere, it now takes 55 milliliters (mL) less water to produce a gram of sorghum grain than it did in 1958. Fifty-five mL is equal to about one-fourth of a cup of water.
This may not seem like a lot of water savings, but spread over the large acreage of sorghum and wheat grown in Kansas, the more efficient use of water now compared to 1958 should have a large impact. Hopefully this information will help you sleep a little easier knowing that some of your crops might not need the all of the moister you thought they needed during this drought.
— Ryan Flaming is a Kansas State Research and Extension Agent for Harvey County. Agriculture is his specialty.