Golfdom, March 2015

research for real superintendents Hosted by Clark Trossell Ph D clarkthrossell@ bresnan net Super Science A gentle breeze pleAse Impact of turf fans on creepIng bentgrass greens By David McCall T he physiology of creeping bentgrass Agrostis stolonifera L var palustris Huds is negatively impacted during periods of stress decreasing the efficiency of many vital functions Optimal creeping bentgrass growth occurs between 50 and 64 degrees Root development slows as the soil temperature rises above 80 with a loss of functionality at soil temperatures above 86 To mitigate environmental stresses to creeping bentgrass turf fans are used on many golf courses to improve airfow and increase transpiration Te objectives of this research were to 1 spatially quantify benefts of turf fans on the overall health of creeping bentgrass putting greens and 2 determine optimal activation timing to maximize creeping bentgrass performance during summer stress Each main plot consisted of an entire green with a unique fan application no fan activate fan at 70 degrees soil temperature and activate fan at 80 degrees soil temperature Six in play creeping bentgrass Penn A1 A4 greens were equipped with permanent 5 horsepower oscillating turf fans TurfBreeze TB 50 Premium 45000 CFM and compared against three comparable greens without fans The study was repeated once with data collection in 2013 and 2014 Fans were activated when daily soil temperature at 15 inches averaged 70 degrees and 80 degrees Once activated each fan ran continuously throughout all data collections Root depth root zone temperature and canopy temperatures were positively impacted by fans regardless of activation date and were strongly correlated to surface wind speed Surface wind speeds of 9 mph can reduce soil temperatures by 4 degrees Impact was most apparent for the frst 40 feet from the fans Surface airfow ranged from 12 mph 20 feet to 36 mph 70 feet compared to 2 mph on greens with no fans Root zone temperature was negatively correlated with two vegetation indices NDVI and RVI which are used as objective measurements of refectance to quantify turf health Using this correlation refectance maps were generated to predict root zone temperatures across entire greens Duration between fan activation dates was 18 days in 2013 and 36 days in 2014 Late season rooting depth were slightly longer when fans news updAtes March 2015 Golfdom 37 Golfdom com photo by DaviD Mccall field data collection of reflectance and environmental parameters on in play greens to quantify the impact of turf fans on putting greens Cisar retires from florida John cisar ph d retired from the university of florida recently after 28 years he received a B a honors in Botany from rutgers university an M s in floriculture and ornamental horticulture from cornell university and earned his ph d in Biological sciences at the university of rhode island cisar began his academic career at the university of florida ft lauderdale research and education center in 1986 as an assistant professor of environmental horticulture he assembled an impressive record of research and outreach in water quality effluent irrigation on nutrient leaching nitrogen and pesticide fate turfgrass nutrition irrigation efficiency soil water repellency soil amendments evaluation of wetting agents evaluation of plant health products turfgrass physiology bermudagrass and st augustinegrass evaluation and management and much more his work has been supported by the usGa the Gcsaa and the florida turfgrass association among many other segments of the green industry cisar has been a frequent lecturer at the Gcsaas Golf industry show delivering seminars and workshops on warmseason turfgrass management irrigation efficiency and soil and water quality his approachable persona and gregarious charisma infected all around him dr ed nangle chicago district Golf association says he will leave a huge void not just in south florida but all around the world in the turfgrass industry although retired from florida cisar remains active in the green industry as a consultant lecturer researcher and advisor and can be reached at cisarturfdoc@ gmail com were activated early suggesting creeping bentgrass may benefit from extra air movement prior to peak summer stress David McCall and Erik Ervin Ph D are at Virginia Tech University and Dana Sullivan is at TurfScout LLC Greensboro N C David McCall can be reached at dsmccall@ vt edu for more information