Irrigation

Water and Irrigation

• IMPORTANT ISSUES: WATER QUALITY AND QUANTITY 

• CONSERVATION

• TURFGRASS AND WATER

• GRASS PLANT IS 80 TO 95% WATER – AT 60% H20 THE PLANT DIES 

Water and Irrigation

• TURGIDITY: ________________________________________________________________________________ 

• TRANSPIRATION RATE DEPENDS UPON ATMOSPHERIC CONDITIONS:

• TRANSPIRATION RATES ALSO VARY WITH TURF SPECIES AND CULTIVAR

Turfgrass Water Needs

• AN ACRE TURFGRASS CAN LOSE IN EXCESS OF 10,000 GALLONS OF WATER TO THE ATMOSPHERE DAILY – HOT, SUNNY, DRY, WINDY

CONDITIONS

• TURFGRASS NEEDS 60 TO 70 GALLONS OF WATER TO PRODUCE 1 POUND OF DRY MATTER

Water Relations in Turfgrass

• WHEN TRANSPIRATION LOSSES EXCEED ROOT ABSORPTION THE FOLLOWING MAY HAPPEN:

Water Relations in Turfgrass

• LESS _____________________

• REDUCED SHOOT ELONGATION

• DECREASED TURGIDITY AND SUCCULENCE

• METABOLIC PROCESSES BECOME SLOWER

Water Relations in Turfgrass

• SYMPTOMS OF DROUGHT STRESS IN TURFGRASS– LEAVES ________________________________ (OVERERHEATED, WEAK OR DAMAGED ROOT

SYSTEMS, LACK OFWATER)--

• NEVER MOW, AERIFY, FERTILIZE OR DO ANYTHING TO TURF IN DROUGHT STRESS!

 

Soil And Water

•  INFILTRATION RATE: THE SPEED AT WHICH A SOIL CAN ABSORB WATER

• INFILTRATION RATE RANGES FROM 0.1 INCH/HOUR IN CLAY SOILS TO AS MORE THAN 3+ INCHES/ HOUR IN SANDY SOILS

 

Soil And Water

• COMPACTION:

• RESULTS IN THE LOSS OF MACROPORES (Soil structure)

• A CONSIDERABLE DECREASE IN THE INFILTRATION RATE OCCURS

 

Soil And Water

• PERCOLATION: THE MOVEMENT OF WATER DOWN THROUGH A SOIL

• SANDY LOAM SOIL 2 FEET IN 30 MINUTES

• CLAY LOAM 2 FEET IN 4 HOURS 

Soil And Water

• SANDY SOIL

Soil And Water

• CLAY SOILS

TERMS TO KEEP IN MIND:

• FIELD CAPACITY:

 

• PERMENANT WILTING POINT:

• AVALIABLE WATER:

From: http://cru.cahe.wsu.edu/CEPublications/pnw0475/pnw0475.html

TERMS TO KEEP IN MIND:

• ADHESION: THE ATTRACTION BETWEEN WATER MOLECULES AND THE SURFACE OF SOIL PARTICLES

TERMS TO KEEP IN MIND:

• COHESION: THE ATTRACTION BETWEEN MOLECULES OF WATER

 

• EVAPOTRANSPIRATION:

Irrigation

• FACTORS WHICH INFLUENCE THE AMOUNT AND FREQUENCY OF IRRIGATION WATER REQUIRED ARE:– GRASS SPECIES AND CULTIVARS – SOIL TYPE – LEVEL OF MAINTENANCE

Irrigation

– PRECIPITATION AMOUNT AND FREQUENCY

– WEATHER CONDITIONS :• HUMIDITY, WIND AND TEMPERATURE

Determining When Grass Needs Water And Application Rates

• WATER WHEN SYMPTOMS OF MOISTURE STRESS APPEAR– COLOR OF TURF---BLUE-GREEN OR

GRAYISH GREEN

– TRACKING REMAINS-FOOTPRINTS OR MACHINERY TRACKS

• SOIL EXAMINATION----– KNIFE OR SOIL PROBE

– TENSIOMETER

From:http://lieth.ucdavis.edu/Research/tens/97/Tensiometer- “pull’ of water moves gauge

Determining When Grass Needs Water And Application Rates

• MOISTURE METERS WHICH MEASURE ELECTRICAL RESISTANCE BETWEEN ELECTRODES

• http://www.sowacs.com/sensors/gypsum.html• NEAR INFRA RED REFLECTANCE

• http://www.sensortech.com/main_pages/moisture/infrared.htm

• TIME DOMAIN REFLECTOMETRY• http://www.sowacs.com/sensors/tdr.html

Determining Turfgrass Water Needs

• EVAPORATION PANS IN A SUNNY LOCATION

•

Determining When Grass Needs Water And Application Rates

• ESTIMATE OF THE EVAPOTRANSPIRATION– http://ag.arizona.edu/azmet/et1.htm

• COOL SEASON TURF GENERALLY REQUIRES ABOUT

________________________________________________________________________________

• http://www.soils.wisc.edu/wimnext/water.html

 

• How should irrigation be applied?

• A ___________ IRRIGATION APPLIED IN __________________ TO AVOID RUN OFF ONCE OR TWICE A WEEK – BEST IN SOILS WITH ADEQUATE WATER

HOLDING CAPACITY AND DEEPLY ROOTED TURFGRASS

 

• SANDY SOILS SHOULD BE IRRIGATED AT LEAST TWICE A WEEK, OFTEN DAILY WHEN ET IS HIGH- – SAND ONLY HOLDS ABOUT 0.1” OF

WATER/ INCH OF SOIL!

 

• DAILY WATERING IS NOT USUALLY RECOMMENDED---SHALLOW ROOTING OFTEN RESULTS.

– However, on sandy soils daily irrigation is often required through warm dry periods.

• If site specific ET data isn’t available, irrigation to replacement of 75-80% of open pan evaporation is usually adequate for most cool season turf.

Determining Irrigation Needs

• PROPER AMOUNT OF WATER: IS THE SOIL WET TO A DEPTH JUST BELOW THE MAJORITY OF THE ROOT SYSTEM ? – THIS IS USUALLY 4 TO 6 INCHES

• PLACEMENT OF CONTAINERS TO COLLECT

WATER FROM SPRINKLERS----DETERMINATION OF PRECIPITATION RATE

• http://www.bae.ncsu.edu/programs/extension/publicat/wqwm/ag508_6.html

Time of Day to Irrigate

• BEST TIME:

• NIGHT----DISEASE PROBLEMS MAY DEVELOP IF THE GRASS IS DAMP OVERNIGHT (LWD)

Other Water Application

• SYRINGING: LIGHT WATERING LASTING NO LONGER THAN A FEW MINUTES– GENERALLY DON’T WANT TO

______________________________________– BEST PERFORMED EARLY AFTERNOON;

MOST USED ON GOLF COURSE TURF 

 

Some Basics of Sprinkler Irrigation

• Length of irrigation cycle is dependent on soil type.

• Generally, ___________________________ are more effective than one long cycle.

• Many sprinkler types are available to homeowners. (soaker hoses, oscillating, impact, etc)

Some Basics of Sprinkler Irrigation

• Average precipitation rate with average water pressure is around 0.5” per hour.

Test…

• The more hose you put out, the greater the pressure loss… so you must increase watering time in areas where more hose is needed to reach sprinkler.

Some Basics of Sprinkler Irrigation

• Precipitation rate at the edge of the pattern is generally ________________________________ for most types of sprinklers.

• Wind greatly effects distribution pattern of all above ground sprinkler systems.

Some Basics of Sprinkler Irrigation

• In ground systems should be designed with ________________________________to assure even distribution of water.

Head to head coverage

Some Basics of Sprinkler Irrigation

• http://www.rainbird.com/

• http://www.toro.com/landscape/irrigation/index.html

• http://www.arrosage.com/

• http://jessstryker.com/

Effective Coverage and Coefficient of Uniformity

• Older impact type sprinklers actually have about the ___________________________, however these heads are rarely used anymore.

• Rotor driven sprinklers are the most commonly used sprinklers, especially on large sites. Rotor driven sprinklers also have a ________________________________________

• Pop up fixed spray heads generally have a lower ________________________________________. However, they are still commonly used on many residential sites due to their low cost.

Fixed spray head performance.

Fixed spray head performance.