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Wetting Agents and Moisturein Sand-Based Putting GreensDoug KarcherAssociate ProfessorDepartment of HorticultureUniversity of Arkansaskarcher@uark.eduturf.uark.edu
Hydrophobic Rootzone Publications Since 1883, 1200publicationsNative sandy grasslands(CA, FL, and Australia)Currently, 200 pub’s per 5years. (Dekker et al.)Golf greens – 1964(Dorman et al.)
What CausesLocalized DrySpots?
LDS on Sand-Based Greens Water repelled by“waxy” coatingson sand grains Water droppenetration time:5s - 10m
Cause of LDSOrganic coatings on sand grainsLDSLDSHEALTHYHEALTHY
Wetting Agent Efficacy - Golf Course DePan, NLThis golf course was established on native sandy soils. Whichhalf of the fairway was treated with a wetting agent?Courtesy of Coen Ritsema, Alterra, Wageningen, NL
How Do WettingAgents Work?
Wetting Agent Function Acts as a bridge between waxy sand coatings andwater dropletHydrophobicsand grain WaterdropletEventually leach or decomposed by microbesSand remains hydrophobic: TEMPORARY FIX
Wetting Agent in Action Lower surface tension, less dew formation
Athens, Georgia
Can Wetting AgentsReduce IrrigationRequirements?
Irrigation Frequency &Wetting Agent Effects onLDS and Moisture Distribution
Treatment StructureIrrigation threshold (vol. soil moisture) 1.2.3.4.12%10%8%6%( daily)( 2-3 x / week)( 1-2 / week)( extreme drought stress)Wetting agent (Revolution) 1.2.untreated controllabel rate (6 oz / 1000 ft2 / per month)
35014AA6% moisture8% moisture10% moisture12% moisture12300Irrigation JuneJulyAugust
Irrigation threshold 12% soil moisture (daily)untreatedwetting agent
Irrigation threshold 10% soil moisture (2-3x per wk)untreatedwetting agent
Irrigation threshold 8% soil moisture (1-2 x per wk)untreatedwetting agent
Irrigation threshold 6% soil moisture ( 1 / wk)wetting agentuntreated
Surface Soil Moisture Weekly measurementson a 1 x 1 ft. grid Average moisturevalues Moisture variabilitywithin plots
Surface soil moisture (vol. %)DryWetIrrigation thresholds are displayed in sub-plot receiving wetting agent treatment
Surface soil moisture (vol. %)DryWetIrrigation thresholds are displayed in sub-plot receiving wetting agent treatment
Surface soil moisture (vol. %)DryWetIrrigation thresholds are displayed in sub-plot receiving wetting agent treatment
Are There DifferencesAmong WettingAgents?
Wetting Agent Effects on PuttingGreen Moisture Distribution Commonly-used products tested within the same trialTested during frequent, moderate, and infrequentirrigation frequenciesEvaluated LDS and soil moisture at 3 depths
UntreatedborderareasGCSAA Wetting Agent TrialUniversity of ArkansasFayetteville, ARPicture taken 08/04/08
GCSAA Wetting Agent TrialLDS – August 26, 2009Untreated controlCascade PlusPrimerRevolutionMagnusTricureCascade PlusPrimerMagnusUntreated controlRevolution
Volumetric water content at 3 inch depth (%)25ControlCascade PlusMagnusPrimerRevolutionTricure20AAAB AAABABABC ABCB15BCC10FrequentModerateIrrigation regimeGCSAA Wetting Agent Trial - 2008Infrequent
Effect of Cascade Plus Timing on SeasonLong Control of Localized Dry Spot Label: 2 applications 7 d Has not provided season long control in previousstudiesExperimental timing treatments:
controlMay 9 and 16 /July 9 and 16May 9 and 16May 9 and July 9Picture taken 8/4/08
Other Wetting Agents Warrant ConsiderationAmega Sciences TrialHelena Trial
Summary Points Most wetting agent products tested reduced LDS andimproved moisture uniformity w/o adversely affectingmoisture content Many wetting agent products available Find product resulting in uniform and desirable moisturecontent (get a moisture probe!) Univ. of Arkansas will continue WA research Make wetting agents more effective! Couple w/ reduced irrigation frequency to: summer stress decline surface organic matter content summer disease moss and algae water budget
Acknowledgments
Wetting Agents and Moisturein Sand-Based Putting GreensDoug KarcherAssociate ProfessorDepartment of HorticultureUniversity of Arkansaskarcher@uark.eduturf.uark.edu
(Dekker et al.) Golf greens . Irrigation threshold (vol. soil moisture) 1. 12% ( daily) 2. 10% ( 2-3 x / week) 3. 8% ( 1-2 / week) 4. 6% ( extreme drought stress) Wetting agent (Revolution) 1. untreated control 2. 2 label rate (6 oz / 1000 ft / per month) i n. n. B B B C B B B BC AB B B B A A A A 0 50 100 150 200 250 300 350 May June July August mm) 6% moisture 8% moisture 10% moisture .
