Dr. Kevin W. Frank and Dr. J.M. Vargas, Jr.
The winter of 2013-2014 will be remembered for many years to
come. The ice storm of Dec. 21-22
knocked out power for thousands and coated everything, included exposed turf, in
ice. Following the ice storm there was a
brief warm-up Dec. 28-29 immediately followed by a Polar Vortex, a blizzard,
and then another brief warm-up from Jan. 10-13.
The weather events resulted in thick ice sheets forming on many putting
greens with the most severe conditions appearing to be from the Lansing area eastward.
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| Ice from a putting green. |
The primary cause
of death to turfgrass under ice sheets is from oxygen depletion and toxic gas
accumulation from soil microbial respiration. The warmer the soil is when
the ice forms the faster the oxygen is depleted by the microbes and the sooner
toxic anaerobic gases like butanol and ethyl butyrate will form. These gases are what superintendents often
refer to as the smell of death and unfortunately many, including myself, have experienced this smell in the last week. The day
estimates for Poa annua survival under ice range from 45 to 90 days and for
creeping bentgrass from 90 to 120 days.
Currently many putting greens have been covered in ice for greater than
60 days. We have sampled Poa annua under
a 2 inch ice sheet at the Hancock Turfgrass Research Center at MSU weekly for
the last three weeks. Last weeks samples
from 58 days under ice (5 days after sampling) show that ½ of the plugs sampled appear to be dead but we will continue to monitor and sample. Some superintendents have started reporting
similar results in the last week.
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| Poa annua samples, 58 days under ice, 5 days after sampling. |
Many superintendents have been active in trying to clear
snow and remove ice throughout the winter but it has been a nearly impossible process due to frequent snowfall and very cold temperatures that make melting
or physically removing ice very difficult. This might be the winter that Mother Nature dictates turf life and death no matter what actions were taken by superintendents. Unfortunately winter is not over and the upcoming warm temperatures and
melt that will arrive can be just as calamitous especially to Poa annua
greens. Poa annua loses its cold
temperature hardy proteins and begins to take up water quickly as temperatures
warm. As snow melts and water collects
in low lying or poorly draining areas, if the temperature drops below freezing
and ice forms it can crush the swollen crowns of Poa annua plants killing them. The damage resulting from freeze/thaw cycles is typically referred to as crown hydration injury. Despite efforts to squeegee water from
low spots on greens it is difficult to remove all the water and completely prevent crown hydration injury. It has already been a very taxing winter and unfortunately spring doesn't look like it will be any easier. We will continue to update the situation as
spring arrives.
