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

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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

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Irrig

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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