Transcript
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Water Management and Irrigation
Water Management and Irrigation
• Turf 75-85% of plant is composed of water.
• Turf in northeast 1-2” water/week.
• Some functions of water in the plant:
• transport solvents and nutrients
• Involved with P.S.
• Involved in gas exchange
• Cooling the plant
• Soil is the reservoir for holding water for plant use.
• Soil/plant factors that effect water availability for the plant:
a) soil texture - course soils hold less available water
b) Root depth- plant with a 6"root system has half the water available for uptake as a plant with a 12" root system
d) Infiltration Rates
d) Percolation rates
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Transpiration = water loss from plant
Function - gas exchange
- cools plant
- moves plant nutrients, amino acids etc.
Evaporation = water loss from soil. Effected by:
•turf density
•water content
•soil type
Turfgrass Water Use Rates:
Evapotranspiration = (evaporation + transpiration)
California Department of Water resources
Water use rates effected by a) Turf species b) Light-solar radiation and night c) Fertility N/K d) Mowing heights e) Soil types f) Temperature g) atmospheric conditions:
• relative humidity • atmospheric moisture-fog • rain-precipitation • condensation in form of dew • vapor content of
turf canopy • wind
Water use rates can be reduced with chemicals:
PGR’s and Anti-transpirants
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WATER REPLENISHMENT INTO THE ROOT ZONEI ) Precipitation - two major factors:
1) duration2) intensity
- Infiltration Rates
- Percolation rates
1) Need good clean source ( quality)2) Need a good amount (quantity)3) Need a dependable and properly
designed irrigation system
2) Irrigation:
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IRRIGATION SYSTEMS
Evolution of Turfgrass Irrigation Systems
snap valves- hard to find at night, labor intensive, over or under watering
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Computerized systems
Controlled home, office, or field
Turfgrass BMP’s for
Water Quality and Quantity
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Best Management Practices for Water
• Goals
• Promote water conservation
• Preserve and improve water quality
What are Turfgrass BMP’s for water management?
Water Quality
• Best Management Practices for Turfgrass water
• Pesticide
• Fertilizer
Water Quantity or Distribution Management
a) Irrigation system features and technologies that aid in water
conservation
b) Management Practices that aid in water conservation
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Water Quality
• Best Turfgrass Management Practices for water quality.
Practice IPM
Controlling Turfgrass Pests second edition By:Fermanian, Shurtleff, Randell, Wilkinson, Nixon
• Avoid applying fertilizers and pesticides on hard surfaces such as cart paths and road ways• Avoid applying pesticides or fertilizers close to waterways (Establish Buffer Zones)
AVOID HIGH RATES OF SOLUBLE NITROGEN ON A
FREQUENT BASIS OR BEFORE HEAVY RAINFALL
EVENTS
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Water QuantityA) System conservation features conserve water at the source
Isolation valves to isolate and repair leaks
Water Conservation Features that can be retrofitted to both new and older systems:
Install water meters at point of entry to system
Pr = 96.25 x GPMHS x RS*
* Pr = precipitation rateHS = Head spacing RS = Row Spacing
or
Pr = 34650 x gpmº arc x HS x RS
Be aware of sprinkler precipitation rates
Photo USGA Green Section Record Sept./Oct 2000
Check nozzle wear and output
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Use part circles to avoid watering non turf areas
Utilize correct nozzle sizes
Rain Out Switches
Low trajectory nozzles - reduce evaporation or water loss in wind
Low Volume Nozzles
V.S.
High Volume Nozzles
Less Loss Due To:
• Evaporation
• Wind or Drift
• Runoff
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Computerized systems
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Computerized systems allow for:
Greater efficiency
• Run times
• Flow management optimizes programs
• Cycle and soak options
• Irrigation adjustments (water budgeting) from one location
From Office or Home
From Field
Remote off site• Shut down capabilities
• Water adjustment capabilities
Automatic Shut Down
• Rain events
• Electrical Storms
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Monitor weather
Evopotranspiration Rates
Temperature
Humidity
Wind
Turfgrass water use in the Northeast
Tools Available:
Radio
Internet
Television
Rain gages
Evaporation pans
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weather satellites
Irrigation decisions and Management Practices that aid in water conservation
• “Hard to decide when to irrigate”• Apply the optimum amount without over or under watering!
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a) diseaseb) shortened root systemsc) compactiond) algaee) thin or week turff) in general poor plant health
Overwatering can lead to:
P.M. A.M.
rough>fairway>tee>green
• Compacted soils often require lighter and more frequent applications
IRRIGATION TO REPLENISH SOIL WATER
• CT 1-1.5” water per week• If possible “water to replenish” in early morning
Possible sequence -
>Turfgrass species
>Turfgrass use
> Micro-climates/environments
> Slope
> Compaction
> Forecasts
> Cultural practices
Determining irrigation needs (scheduling):Determining irrigation needs:
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>Light intensity
>Precipitation rates of sprinklers
>Nozzle size
>Soil moisture levels using> tensiometers >soil probes
>Soil type
Determining irrigation needs:
Utilize the correct sprinkler head and precipitation rates for soil type and slope
Determining irrigation needs:
2) Check indicator areas
1) Probe soils daily-check moisture content (moisture tensionmeters available)
Determining irrigation needs:
3) Use of wetting agents localized dry spots
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5)Keep an eye on weather-humid weather cut back-syringe if needed.
6)Hold off on irrigating as long as possible-however, soil hard to re-wet once it dries out
4)Water as close to daylight as possible
-this reduces time of leaf wetness -reduces over watering if sprinkler sticks
Determining irrigation needs:
Wilt Signs• Loss of turgidity• Turns blue in color• Foot printing
WATER MANAGEMENT:WILT / HEAT / DROUGHT *
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Heat stress
Two types:
1. IndirectIn general when air and soil temperatures exceed 86ºF for extended periods• result reduction in root and shoot
growth• increase in respiration and reduction
carbohydrate production
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Damage from golf carts driving on water stress (wilted) turf
Photos USGA Green Section Record
2. Direct• Occurs with rapid increase in
temperature i.e. 104º F for short time
• Most common type of direct is scald
•Scald (Direct Heat Stress)Hot sunny daysRapid heat build up >104 ºFStanding water or in some cases
in extremely saturated thatchRapid loss of oxygen Death within hours
Turf may be killed by combination of:• excessively wet soils• high day and nighttime temperatures• mechanical injury from mowers when mowing
under wet conditions
Scald on bentgrass tee photo: Peter H. Dernoeden PH.D USGA Green Section Article March April 2006
Understanding Wet Wilt by Peter H. Dernoeden PH.D
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Wet Wilt•Bridges Direct and Indirect•Transpiration loss greater than uptake but water is in soil. •Occurs when limited root system.
Conditions favoring wet wilt:•Water on surface or in thatch absorbs heat from sun•Soil temperatures in putting greens on hot sunny days may be hotter than air temp.•Water logged soils
•High temp and humidity with extended precipitation
Annual bluegrass putting green damaged by spiking in the heat of the day during a wet wilt event Photo: Peter H. Dernoeden PH.D
USGA Green Section, March April 2006 , Understanding Wet Wilt
Syringe for wilt:Dry wilt•Transpiration greater than water uptake by roots•Hot, dry, windy, bright days
Wet Wilt•Transpiration loss greater than uptake
•Saturated or waterlogged conditions
•Limited root system.
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Syringing - light application of water to cool off plant and slow transpiration rates. No wetting or soil water replenishment.
Syringing to alleviate wilt
TGIF- The necessity of hand watering greens
http://www.youtube.com/watch?v=kw9ufwNLr7Q
Aerate to relieve compaction and increase water infiltration to the rootzone
Irrigate in early morning to reduce water loss due to evaporation and wind
Raise mowing heights > increased root growth > increase water availability
Utilize a well balanced fertilizer plan for the turf species being grown
Designate naturalized areas for lower maintenance and water use
Management Practices to reduce water input under dry conditions and water conservation
Rackliffe and Troll (1982)
Management Practices continued:
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Utilize wetting agents to improve water infiltration
Through Irrigation systems
Sprayer
or
granular
Hose
Management Practices continued:
Wetting AgentsSurfactants = chemicals that cause a physical change at the surface of liquids.
Thus SURFice ACTive AgeNTS
Surfactants include- wetting agents, spreaders, stickers, emulsifiers, detergents, dispersants etc.
Management Practices continued:
In Turf
• Most wetting agents - Non Ionic- (No Charge-thus they will not react with other ions in the soil)
• All contain a water-soluble hyrophilic group attached to a oil-soluble (lipophilic group)
Characteristics and Terminology
Wetting agent molecule Water soluble
group (polar) hydrophilic
OIL-Soluble Hydocarbon group (non polar) hydrophobic
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H+ H+
O-
•Polarity- i.e. water is dipolar (both negative and positive ends)
•Water will not bond with non polar molecules- in fact water would be repelled by non polar substances
•Most organic matter is non-polar
• Non Polar portion of the wetting Agent will bond with non polar portion organic matter
• Polar portion of wetting agent will bond with water
Sand particle
Water-repellent organic coating with non polar ends that repel water
Wetting Agent polar end attracts water (hydrophilic)
H HO
H HO
H HO
H HO
H HO
H HO
H HO
•600 Golf Course Superintendents
• 87% use wetting agents as part of regular maintenance program
• 11% use them in “certain situations”
Four primary purposes:
• 42% relieve localized dry spot
• 32% to aid in water management
• 11% improve soil drainage particularly on non-water repellent soils
• 9% improve pesticide and fertilizer performanceSource Golf Course Mgt. June 2004, Keith Karnok Ph.D. University of GA
Survey
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Other uses:
• Relieve surface tension of water
• Remove morning dew
• Suppress poa annua seed head (early 90’s)
• Reduce run-off
• Summer stress reduction
• Water usage reduced
Water drop without wetting agent
Water drop with wetting agent applied
Low contact angle
High contact angle
• Numerous Wetting Agents
• All vary significantly
• Different label rates
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