By Kim Tiber, University of Minnesota
This article was originally published on the UMN Turfgrass Science blog.
Previous work under the Icebreaker study has shown that annual bluegrass on golf putting greens is highly susceptible to winter kill or damage due to ice encasement. During the winter of 2022-2023 carbon dioxide levels were above the upper limit of the sensor for an extended period.
Last winter work began to develop a methodology for further exploring the relationship between carbon dioxide levels and winter kill on annual bluegrass greens. That work continues during the current winter of 2024-2025 as sub-surface air samples will be extracted below ice-encased annual bluegrass on a golf putting green (Figure 1).
These samples will be analyzed in the lab to see if there are compounds present that indicate plant death or if there are toxic compounds present that may be causing plant death or injury. USDA soil scientists are also extracting samples from these plots and using known lab methods to determine carbon dioxide and oxygen levels that can be checked against readings taken by the data logger sensor installed in the same plot.
Ice-making operations began on December 2, 2024 (Figure 2). We are currently just beyond the 60-day mark on days under ice encasement, with the goal of hopefully reaching at least 90 days of ice cover. This winter has been pretty variable so far with some pretty warm temperatures, some pretty cold temperatures and just a little bit of snow here and there (Figures 3 and 4). So far we have been able to maintain continuous ice cover through the warm days and then build the ice back up again when it gets cold enough to make ice, so it can withstand the next warm spell.
Will we make it to 90 days of ice cover this year? Only time will tell. For a more detailed look at the variability of this year’s weather and how it’s impacted ice on these plots check out this Story Map: Annual bluegrass ice encasement 2024-2025.