The reports of cold-temperature injury are growing as the snowpack recedes and the soils thaw. The damage is widespread throughout most of the region. Golf courses in metropolitan areas of New York and Boston, the Berkshire region, Vermont, New Hampshire, Maine, upstate New York, Ontario and Quebec have reported injury. The injury in some areas is very severe. The patterns of injury reported, and that which we have seen, indicate that several mechanisms were at work this winter. This makes sense considering the scope and long duration of the winter we experienced. Understanding, or even trying to explain, the injury patterns is always a challenge because several variables, including site characteristics (e.g., surface drainage, sun and wind exposure, soil type, grasses etc.) and weather events, ultimately dictate where winter injury will occur and how severe it will be. This is what has been observed so far in the field.
- Damage from direct cold temperature has been more evident this season, and it most likely occurred during one of the flash-freeze events we experienced in January. Temperatures during those events fell 40-50 degrees in a fairly short time, which in itself is often lethal to annual bluegrass. Uncovered areas where turf was directly exposed to very cold temperatures are most prone to this type of injury. This form of injury causes more widespread damage on exposed surfaces rather than only impacting low-lying areas.
- Crown hydration injury patterns are evident in lower swales and pockets. However, this damage can be confused with direct cold-temperature injury. This injury usually develops when freeze/thaw cycles occur as annual bluegrass begins to break dormancy and transition into spring. Turf that has been encased in ice usually has a reduced ability to tolerate cold temperature and is especially prone to this type of damage. This damage typically occurs in low-lying, saturated areas when turf emerging from dormancy is exposed to freezing temperatures after imbibing water from ice and snow melt during mid-to-late winter. Several superintendents feel their annual bluegrass deteriorated during this transitional period. There is a good chance that crown hydration was the mechanism for that injury.
- Anoxia – low oxygen levels – resulting from extended ice encasement or impermeable covers was also responsible for some of the injury that has occurred. The telltale “smell of death” was apparent at many golf courses as the ice layers began to melt and the surfaces were exposed. Under the right circumstances, a dense layer of ice directly encasing the turf or heavy layers of ice and snow lying above an impermeable cover can begin to create anoxic conditions within a 40-day period. Venting programs for covered greens can help reduce anoxic conditions. Anoxia can also affect turf indirectly by reducing the plant’s ability to tolerate other types of winter injury. Many golf courses were under snow and ice cover for 100 or more days this season providing ample opportunity for anoxia damage. We have observed some lower pockets under persistent ice coverage and some isolated areas below impermeable covers that have succumb to anoxia.
So, if your golf course has experienced cold-temperature injury you are not alone. Multiple forms of damage may be present on the same green, which can get confusing. Ultimately, much of the damage in the Northeast region was caused by cold temperature and the susceptibility of annual bluegrass to winter injury. At the writing of this update we are experiencing yet another freeze that was preceded by some very warm temperatures, reminding us that this is not over yet.
Hopefully, a recovery plan is in place or is already underway to restore damaged areas at your golf course. The articles Recovery for Winter-Injured Greens and Recipe for Rapid Recovery from Winter Injury provide information on recovery programs. We urge you to contact our offices if we can help evaluate winter damaged surfaces, help develop an effective recovery program, or look at some steps that can be taken to reduce concerns with cold-temperature damage in the future.
Source: Jim Skorulski firstname.lastname@example.org
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