Bernd Leinauer, Guillermo Alvarez, Matteo Serena, Elena Sevostianova New Mexico State University Las Cruces, NM
Turfgrass Water Conservation
Seminar Series – Growing Turf When Water is Scarce Department of Crop Science Lab. of Floriculture and Landscape Architecture Agricultural University of Athens
Turfgrass Irrigation Requirement Las Cruces, NM (2005 – 2009)
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EToPrecipitationWarm-SeasonCool-Season
Irrig
atio
n
Water
Conservation
1)Residential potable water consumption doubles in summer compared to winter
2) Approximately 50% of domestic water use in the Southwest is used for landscape irrigation (Devitt and Morris, 2008; Kjelgreen et al., 2000)
Data provided by City of Las Cruces – Water Utilities
Problem
Benefits of Turf
Environmental Recreational Aesthetic
Conservation of urban soils
Low cost surfaces Beauty
Erosion control Physical health Quality of life Dust prevention Mental health Mental health
Heat dissipation Safety Social harmony Noise abatement Spectator
entertainment Compliments trees and shrubs Air pollution
control Beard, 2008
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Cash value of Agricultural Products (incl. Golf) in New Mexico (2001)
NMDA, 2003
NMSU Golf Course: 36.4 ha (irrigated) (9 CS & 27.4 WS) 986 mm/yr Water Requirement (ET): CS: 1350 mm/yr WS: 860 mm/yr (Leinauer and Smeal, 2012)
Lower Rio Grande Valley: Pecan Trees on 11,000 ha Water Requirement (ET): 1000 mm/yr (Samani et al., 2009)
The industry is directly and indirectly responsible for:
• over 20,000 jobs • over $400 million in personal income • over $83 million in tax impacts
Cost of water • Nevada:
– $1.30/1000 gal ($0.35 / 1000l) – 250 millions gal (950 x 106 l) used in 2007 – $325,000 / course
• Arizona: – Golf courses spend $275,000 per year on water – Required: any new golf course must have their own
source of water – Third highest per round green fees (behind Hawaii
and Nevada)
Strategies for Irrigation Water Conservation
1. Artificial Turf 2. Reduce area under
irrigation 3. Irrigation with
recycled/impaired water
4. Use of low water use turfgrass species
5. Accept quality reduction 6. Increase irrigation
efficiency I. Scheduling
a) Climate data b) Soil water status
II. Improve Water Distribution
Strategies for Irrigation Water Conservation
1. Artificial Turf 2. Reduce area under
irrigation 3. Irrigation with
recycled/impaired water
4. Use of adapted / native (low water use) turfgrass species
5. Accept quality reduction 6. Increase irrigation
efficiency I. Scheduling
a) Climate data b) Soil water status
II. Improve Water Distribution
12
K. Bluegrass
Hard Fescue
Prairie Junegrass (Koeleria macrantha)
Alkaligrass (removed)
Cool Season Grasses
Crested wheatgrass (Agropyron crystatum)
Courtesy D. Smeal, NMSU
13 57
14 58
Mean Summer Evapotranspiration Rates of Different Turf Species
ET rate Cool season Warm season
in/wk mm/day 2.0 – 3.5 7.2 – 12.6 Tall Fescue
1.8 – 3.1 6.6 – 11.2 Perennial ryegrass
1.7 – 2.2 6.2 – 8.1 Seashore paspalum 1.6 5.7 Blue grama 1.5 – 2.0 5.3 – 7.3 Buffalograss 1.0 – 2.2 4.0 – 8.7 Bermudagrass 1.3 – 2.1 4.8 – 7.6 Zoysiagrass 1.1 – 1.8 4.1 – 6.6 Kentucky bluegrass
Gaussoin, 2003
Buffalograss - Water Use (Stewart et al., 2004)
• No difference in water extraction between buffalograss and Kentucky bluegrass for well watered conditions
Incipient water stress: • Kentucky bluegrass depleted 50% of soil water
to 30 cm depth (6 days) • Buffalograss depleted 60% of soil water
to 90 cm depth (20 days)
Conclusion 1) Traditional cool season grasses may perform adequately even
with less water than historically been thought 2) “high water use grasses” may perform equal (or better) than
“low water use grasses” at the same reduced amount of irrigation
3) In order to make useful recommendations, regional testing under water limiting conditions is necessary
4) Consider additional stresses, e.g. salinity, traffic
Leinauer, B., V. Gibeault, L. Lauriault, R. Autio, S. Cockerham, R. Kirksey, and S. Ries. 2005. Assessing Establishment Rates and Winter Survival of Low Maintenance Turfgrasses in Two Climate Zones. Intl. Turfgrass Society Res. J. Annexe. 46, 47.
Water Use vs. Drought Resistance
Drought avoidance: Ability to avoid tissue damaging water deficits
Drought tolerance: Ability to endure low tissue water deficits
Water Use (ET) is not synonymous with the plant’s ability to resist drought
o Seashore paspalum o Tall fescue
o Deep root system o Reduced leaf area (rolled,
folded leaf blades) o Leaf orientation and extension o Dormancy
o Hardiness to low tissue water deficits
o Dormancy
o St. Augustinegrass
o Kentucky bluegrass o Bermudagrass o Buffalograss
Irrigation = (ETo x 0.7) / DU
Strategies for Irrigation Water Conservation
1. Artificial Turf 2. Reduce area under
irrigation 3. Irrigation with
recycled/impaired water
4. Use of adapted / native (low water use) turfgrass species
5. Accept quality reduction 6. Increase irrigation
efficiency I. Scheduling
a) Climate data b) Soil water status
II. Improve Water Distribution
GCM, June 2011
Turfgrass water use or irrigation (in)efficiency?
• Mecham (2004): Summary of uniformity data from over 6800 irrigation audits (Utah, Nevada, Colorado, Arizona, Texas, Oregon, and Florida)
• Average DU of 0.5 • The amount of irrigation water
doubles compared to what “the grass plant needs” to maintain an adequate quality level
August 2005 August 2009
August 2011
The natural progression of a modern sprinkler system
A. New Sprinkler Technology
• No significant technology change since valve-in-head (except streaming heads?). Most changes have been in irrigation design (nozzles, more heads, shorter throw) and scheduling
• Sprinkler system’s distribution uniformity affected by pressure, flow rate, nozzles, wind, area size, shape … etc.
• New heads and nozzles may address certain problems, but not all
Hunter MP Rotator
Toro PrecisionTM Series
Test Again
Microirrigation
(Subsurface –) Drip Irrigation
Line source (Precision porous pipe)
Point source (Netafim, Toro)
Hybrid (KISSS)
Subirrigation
Cellsystem
ECS
Pat System, Purr-Wick System
B. Subsurface Irrigation
• Extensively used in agriculture
• Slow to reach acceptance in turf
0.70
1.03
0.650.70
1.04
0.64
0.51
1.11
0.56
0.33
0.73
0.43
0.00
0.20
0.40
0.60
0.80
1.00
1.20
2004 2005 2006
Irrig
atio
n /
ETp
Cal Sp USGA Sp USGA Dr ECS
Average Irrigation June - August
- 53%
- 30%
- 33%
SUBSURFACE DRIP IRRIGATION (SDI)
• Emitter spacing - depth • Soil type • Grass type (rooting depth) • Water pressure • Elevation changes
fits all shapes
golf courses use drip irrigation on bunker faces
Seashore paspalum NTEP variety trial Subsurface drip irrigated with saline water
November 2009
Summer 2009
Bermudagrass NTEP variety trial Subsurface drip irrigated with saline water
Summer 2009
November 2009
August 2012
Drip Sprinkler
3 years of potable irrigation @ 50% ETo
Bermudagrass
Seashore p.
Research perspective - Conclusions
1) Subsurface drip irrigation can be used to irrigate turf efficiently
2) also in combination with saline water 3) is a viable alternative to traditional sprinkler
systems if installed, monitored, and maintained properly
4) http://ucanr.edu/sites/turfgrassfieldday/files/153341.pdf
Maintenance + Operation
Filtration
Subirrigation
Reasons for not gaining market acceptance: • Lack of urgency to conserve water • Cost • Considered to be “unproven” technology • Considered technology predominantly for
tees and greens (how much water can you conserve on 2.5 to 3.5 ha when 40 ha are irrigated?
• Performance questionable on sloping design
A. Soil Sensors
• Powerful tool as it relates directly to plant available soil moisture
• Accuracy can be affected by salinity • Dielectric sensors not only measure
moisture but also temperature and estimate salinity
Remote Sensing
Colony West #9
Color NDVI <0.73
0.73-0.75
0.75-0.77
0.77-0.79
>0.79
690 heads using an average radius of 97’ (30 m)
Based on these two heads which are ~97’ (30 m) apart
17 heads running
Typical irrigation
Colony West #9
Color NDVI <0.73
0.73-0.75
0.75-0.77
0.77-0.79
>0.79
690 heads using an average radius of 97’ (30 m) Based on these two heads which are ~97’ (30 m) apart
10 heads running
Reflectance based irrigation
The numbers
Typical irrigation: – 17 heads – 31,212 gallons of water (120.000 l)
Reflectance based irrigation: – 10 heads – 18,360 gallons of water (70.000 l)
Assumptions: − 690 Series Rotors, Nozzle set 91, 80 PSI − Run system for 30 min and all stress is water stress − 61.2 GPM (230 l)
Save 12,852 gallons or 50.000 l with one irrigation
“PS 6000” Data Collection Vehicle
Spectrometers measure turf vigor
Soil sensors measure moisture & salinity content plus compaction
GPS provides latitude & longitude referencing and elevation data
Foamer provides navigation
“PS 6000” Data Collection Vehicle
Spectrometers measure turf vigor
Soil sensors measure moisture & salinity content plus compaction GPS provides latitude &
longitude referencing and elevation data
Foamer provides navigation
On-board computer processes & logs sensor data
• Soil moisture • Soil salinity • Soil compaction • Turf quality • Topographic relief
GIS
Sampled data is Interpolated using “kriging”* to create spatial distribution maps of site attributes.
* a distance-weighted averaging linear least squares estimation algorithm
Sampled data points for VWC 8’ x 8-16” grid
Sample data interpolated to a 2‘ x 2' grid
Data Interpretation • Sample data ~1 pt./100 ft2
• 435 pts./ac. or ~1000 pts./frwy • Interpolated data 1 pt./4 ft2 • Or ~25,000 pts./frwy
Soil moisture variation & Topographic relief Measured by TDR & GPS elevation
Soil Moisture (VWC)
< 25% 25 - 30% 30 - 35% 35 - 40% 40 - 45% 45 - 50% 50 - 55% 55 - 60% 60 - 65% > 65%
Dry Soil
Wet Soil
Soil moisture distribution depicted in 3D
Irrigation Auditing
Sprinkler heads
10’ 20’ 30’ 40’ 50’ 60’ 70’
Frwy #16 Head 1-162-4 MU 64.6% Directional variation 21.5% Pattern scale 43.6%
Irrigation Auditing Evaluating soil moisture distribution around individual sprinkler heads
Turfgrass Water Conservation - Conclusions
1) Some strategies have obvious and immediate impact (reduced irrigated area, use of non-potable water)
2) Major emphasis placed on low water use species/ varieties, however significant impact questionable because acceptable turf quality still deciding factor
3) Research on new scheduling technologies show promising first results
4) Subsurface systems can be a viable alternative to traditional sprinkler systems if installed, monitored, and maintained properly