Do your greens look tired in hot weather even when you irrigate sufficiently? The answer may lie in the soil gas profile. High temperature and soil moisture results in elevated soil CO2 and decreased soil O2 to levels that can be detrimental to bentgrass on golf course putting greens. Roots need O2 for respiration and give off CO2 in the process. Gas exchange from the soil to the air must occur to allow O2 infiltration and avoid CO2 buildup. That’s why soil aerification is important.
Researchers at Clemson University artificially elevated CO2 in a USGA specification bentgrass putting green to learn more about soil atmosphere effects. They found that root mass and depth decreased by 40% when the CO2 level was raised above 2.5% for 20 days, but turf quality did not suffer visually. When the soil CO2 was raised to 10%, visual quality became unacceptable. The researchers warned that high soil CO2 could predispose turf to other stress factors.