Wednesday, November 15, 2006

Field Assessment of Winter Injury on Creeping Bentgrass and Annual Bluegrass Putting Greens.

David Minner, Federico Valverde, Deying Li, Nick Christians, and John Newton. iowa state university, horticulture hall, ames, IA 50011

Some level of winter injury occurs every year on putting greens and fairways in Iowa and other golf courses north of the transition zone. The purpose of the research was to quantify the relative injury on putting greens as it relates to snow cover, ice formation, desiccation, crown hydration, and freeze/thaw cycles. This study was conducted at the Iowa State University Horticulture Research Farm and at Veenker Memorial Golf Course, both in Ames Iowa. The species evaluated were creeping bentgrass (Agrostis stolonifera L.) and annual bluegrass (Poa annua L.). Ten possible winter scenarios; dry/open, wet, ice continuous, snow continuous, impermeable tarp + ice,  ice removal, ice/melt freeze, snow removal/melt freeze, evergreen turf cover, and evergreen turf cover with snow removed, were created on two Iowa putting greens in Jan, Feb and Mar of  2003, 2004, and 2005. Dry weight yields of plant samples recovered in the greenhouse were used to indicate the amount of winter injury. Creeping bentgrass was not killed under any treatment. Continuous ice cover for 66 days caused creeping bentgrass bleaching but never resulted in any turf kill or decline in creeping bentgrass cover. Poa annua was susceptible to winter injury under ice covered plots.  The formation of ice may be more important than the duration of ice cover in predicting Poa annua winter injury when ice is present.