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7/17/2015
1
Improving Water Use in the Landscape
MAUREEN THIESSEN
COMMERCIAL ORNAMENTAL AREA SPECIALIST
TENNESSEE STATE UNIVERSITY, UNIVERSITY OF TENNESSEE
Purpose of irrigation
system
To deliver adequate water to plantings such that manual methods
are reduced as much as possible.
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2
Objectives
Identify problems associated with improper irrigation management
Understand landscape and environmental elements that should be considered in
irrigation design
Learn how to account for those elements in irrigation design using appropriate equipment and scheduling
Reasons to be conscientious
about water
Plant health, disease
Root Establishment
Water availability
Environmental conservation
Maintain a professional look
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3
Photo: Savelandscapewater.org
Photo: Forester University
Photo: Turfdiseases.org
Photo: University of Florida
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Cost of
Municipal WaterAlliance for Water Works
27,154 gallons
Cost of
Municipal WaterAlliance for Water Works
6,788 gallons
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Cost of
Municipal Water
One inch of water applied over an acre is 27,154
gallons
One-quarter acre-inch = 6,788 gallons
Within City:
$3.47/1000gal + base
($3.47 x 6.788gal) + ($4.46) =
$28.00 per inch of applied
water per quarter acre
Alliance for Water Works
Outside City:
$6.94/1000gal + base
($6.94 x 6.788gal + $8.92)
$56.03 per inch of applied
water per quarter acre
Johnson City Water Rates (not including sewer)
Scheduling considerationsMother Nature’s Resources
Plant type
Some plants require more than others
Soil
Infiltration - Different soil types absorb
water at differing rates
Water holding capacity - Some soils hold
more water than others
Topography
Weather
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Estimating plant requirements
Do not water entire landscape according to one
plant type’s needs
Separate zones with differing water requirements
Consider rooting depth
Minimum – separate beds and turf
Photo: Alliance for water efficiency Photo: LSU AgCenter
Turfgrass
Area of the landscape with highest density of photosynthesizing tissue -highest evaporative demand.
Up to 1.5 inches a week
More frequent
watering
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Ornamental – trees, shrub
beds
Do not need as much water as turf
Hardier than turf and annuals
Deep rooting
Fewer applications, higher volume
Pictures: Ball Seed
Ornamental – annual beds
Generally shallower root systems, dry out more quickly
Tender foliage
Water more often with less volume
Pictures: Ball Seed
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Water Requirements of Plants
Dry Soils
Box Elder
Redbud
Smoketree
Hawthorn
Walnut
Pines
Quince
Junipers
Photinia
Spirea
Wet Soils
River Birch
Silver Maple
White Ash
Magnolia
Sycamore
Bald Cypress
Japanese Cedar
Forsythia
Hydrangea
Beautyberry
Other considerations
New turf will need more frequent, smaller
applications of water
Reduce erosion, but supply adequate water to
young roots
Gradually increase time between
irrigations to encourage deeper rooting.
New ornamental plantings should be
watered-in, but allowed periods of
dryness to encourage rooting.
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Scheduling considerationsMother Nature’s Resources
Plant type
Some plants require more than
others
Soil
Infiltration - Different soil types
absorb water at differing rates
Water holding capacity - Some soils
hold more water than others
Topography
Weather
Why is the soil important?
Soil types hold different amounts of water and
for different amounts of time.
Water Holding Capacity (WHC) or Field
Capacity (FC)
Soil types absorb water at different rates
Infiltration Rate (IR)
Affects how much and how often you apply
water
Texture, structure, and topography
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Texture – the particles
Three textural classes –
sand, silt, and clay
Proportions of each
class determines ability
and length of time to
absorb and hold water
Sand Silt Clay
Loose, gritty
Very permeable
Easily leached
Low WHC
High porosity
Crumbly
Less permeable
Downward and lateral movement
similar
Higher WHC
Medium porosity
Sticky, moldable
Least permeable
Susceptible to runoff
Higher WHC
Low porosity
http://i3.photobucket.com/albums/y51/wilddog_202/Clayafteryearsoforganicmatter.jpgPhoto: https://ncptt.nps.govPhoto: Salinitymanagement.org
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11
Soil Water-Holding Capacity
Ron Sheffield, LSU AgCenter
COARSE >>>>>>>>>>>>>>>>>>>>>>>>>>FINE
Maximum water it can hold
Moisture content
at wilting (how
tightly water is
held.
Water-Holding Capacity
and Retention
Hillel. Introduction to Environmental Soil Physics, 2004.
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Infiltration
Hillel. Introduction to Environmental Soil Physics, 2004.
Soil Texture and Infiltration
Clays have slow infiltration rates but stay wet longer
Sands have quick infiltration rates, and dry out more quickly
Application rate should not exceed the rate of infiltration
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Structure – how the
particles fit together
Aggregation increases
porosity (O2 and H20) and
infiltration
Often altered by construction
Severe compaction
Lack of OM and aggregation
Increased runoff, limited
rooting
Tillage, OM amending, and
mounding, adjust irrigation to
apply more slowly.
Photo: Colorado State University
Scheduling considerationsMother Nature’s Resources
Plant type
Some plants require more than
others
Soil
Infiltration - Different soil types
absorb water at differing rates
Water holding capacity - Some
soils hold more water than others
Topography
Weather
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14
Landscape Topography
Slopes lower infiltration rate
Increased runoff
Lower application rate or divide
total irrigation into multiple
applications
Slopes can cause different areas
of the landscape to be
wetter/drier than others.
Put low lying areas on different
zone
LandscapingNetwork.com
Slope and Soil Texture
Rainbird ® Irrigation Design Manual
7/17/2015
15
Scheduling considerationsMother Nature’s Resources
Plant type
Some plants require more than
others
Soil
Infiltration - Different soil types
absorb water at differing rates
Water holding capacity - Some
soils hold more water than others
Topography
Weather
Weather
Irrigation needs affected by
precipitation, temperature, sunlight
Evapotranspiration – water loss from
landscape to the atmosphere through
evaporation and plant transpiration
Consider season
Make sure your irrigation program
changes throughout the year
Differences in rainfall, temperature,
plant dormancy
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16
Weather
Average Annual PrecipitationTN Climatological Service
Weather patterns can be unpredictable
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17
Scheduling considerationsMother Nature’s Resources
Plant type
Some plants require more than
others
Soil
Infiltration - Different soil types
absorb water at differing rates
Water holding capacity - Some
soils hold more water than others
Topography
Weather
Design
The efficiency of an irrigation system is limited by its design.
Proper zoning
Proper output
Application rate awareness
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Hydrozones
Use zones to separate areas of different
water need, as well as deal with limited
available pressure.
Zones should take into account the plant
type needs and the soil characteristics
Separate areas that tend to stay dry/wet
If you water it differently, tap it differently!
Make sure design pressure of each zone
doesn’t exceed what is available.
Rainbird® Irrigation Basics Manual p.16
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Delivery Methods
Things to always keep in mind
Radius of throw
Operating pressure
Flow rate
Precipitation rate or application rate
Sprinklers
Impact, rotor, gear-driven
High flow (2-16gpm), high pressure requirements (30-80psi)
Bigger radius of coverage (65ft)
Single stream or multistream
Generally used on large, open turf areas
http://recreational-turf.wikispaces.com/file/view/40.jpg/186231979/40.jpg
Rainbird®
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Sprayers
Medium flow (1-5gpm), medium pressure
Smaller area of coverage (10-30 feet)
Come in variety of spray shapes
http://www.hunterindustries.com/irrigation-product/spray-bodies/ps-ultra#
Drip Irrigation
Most precise placement of water - applies directly to root
zone
Much lower flow rate (gallons per hour) and pressure
requirements (10 – 50psi)
http://www.hunterindustries.com/sites/default/files/styles/product_header/public/580x325_product_slider_00-pse-
7.jpg?itok=v1Tt31aM
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21
Drip Irrigation
Consists of tubing – emitter – microsprayer design to deliver
water to individual plants.
Least loss to evaporation
Higher installation cost, more likely to clog, but most
efficient
Keeps foliage from getting wet
http://www.hunterindustries.com/irrigation-product/micro-irrigation/micro-sprays#
https://rainbird.com/landscape/products/dripEmission/XeriBugEmitters.htm
Drip Irrigation
Filters and pressure regulators especially important
Some filters are pressure – regulating
Kits are available with included valve, filter,
pressure regulator components
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Precipitation Rate
Proper timing needs to take into account precipitation rate
For one given flow rate:
0.24” per
hour
0.32” per
hour
0.48” per
hour
0.96” per
hour
1X 4X2X1.3X
Know your precipitation rate
Rotating heads
usually do not adjust
flow rate for variable
arcs
Adjust GPM in your
calculations
accordingly
Always check
performance charts
7/17/2015
23
Know your precipitation rate
Matched Precipitation rate
(MPR) nozzles usually
available as “series”
Can also be variable /
adjustable arc nozzles
GPM is adjusted according
to arc to keep precipitation
rate constant.
Common in spray bodies
Always check performance
charts
Know your zone
precipitation rate…
Check performance chart data
BE CAREFUL – rotor performance data often based on
half circle operation
Therefore, divide precipitation by 2 if using 360˚ rotation
S
S
S
𝑃𝑅 =96.3 𝑋 𝐺𝑃𝑀
𝑆2𝑃𝑅 =
96.3 𝑋 𝐺𝑃𝑀
0.866 𝑋 𝑆2
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Know Your Precipitation
Rate…
AWS Irrigation
Controllers
Need to maintain flexibility
You/client are the irrigation manager, not
the clock
Consider user-friendliness, especially for homeowners
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Weather and
Location
Sensors
Rain
Soil Moisture
More sophisticated scheduling exists using ET data along with other weather parameters
Generally require weather station
Example: Hunter® ET System
When is the best time?
Efficiency
Midday irrigation offers cooling,
but is the most inefficient time of
day due to evaporative loss
Nighttime irrigation has greatest
chance for disease development
Early morning hours (5-9) allow time
for foliage to dry
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How Often?
Plant age
How established are the roots?
Consider season
Do not use one irrigation program for entire year
Differences in rainfall, temperature, plant dormancy
How Much?
Season
Imagine cost of 1” per week
for 52 weeks per year…
Rooting depth and establishment
Canopy Cover
How dense is the canopy, or
leaf area, of the area to be irrigated?
Turf vs. woody vs. annual
New plantings vs. established
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Remember
Design the system so water is placed uniformly and efficiently
Remember to consider plant type and establishment, soil type and condition, sloping, shading, and time of day.
Observe irrigation system performance after installation and routinely, adjust accordingly
Explore available technology that accounts for rain and existent soil moisture.
Reference Material
“Fertilization and Management of Home Lawns.” Publication 1038. University of Tennessee Agricultural Extension Service. <https://extension.tennessee.edu/publications/Documents/PB1038.pdf>.
Wells, Wayne. “Establish and Manage Your Home Lawn.” Publication 1322 Mississippi State University Cooperative Extension. http://msucares.com/pubs/publications/p1322.pdf.
“Growing Tree Fruits Successfully.” Online Presentation. Oregon State University Extension Service. http://extension.oregonstate.edu/lane/sites/default/files/documents/tree_fruit.tf_specialists.pdf.
Stein, Larry, and Welsh, Doug. “Efficient Use of Water in the Garden Landscape.” Texas A&M AgrilLife Extension. http://aggie-horticulture.tamu.edu/earthkind/drought/efficient-use-of-water-in-the-garden-and-landscape/.
Sheffield, Ron, and Thomas, Dan. “Irrigation Basics for Landscape Contractors.” Irrigation Contractor Class Manual. LSU AgCenter.
Sheffield, Ron. “Irrigation Basics of Irrigation Contractors.” LSU AgCenter. http://www.lsuagcenter.com/en/our_offices/departments/Biological_Ag_Engineering/Features/Extension/Agriculture_and_Environment/Irrigation/Irrigation-Basics-for-Irrigation-Landscape-Contractors.htm>.
Smith, Bryan W. “Irrigation.” Series on Landscape Irrigation Basics. Clemson University Extension. http://www.clemson.edu/extension/hgic/plants/other/irrigation/.
7/17/2015
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Questions?
Contact Me:
Maureen Thiessen
Area Specialist
Commercial Ornamentals, Eastern Region
423 – 798 – 1710
Greeneville County Extension Office
Thank You!