What is Sustainable Lawn Care? Keys to Sustainable Lawn ... · Practices for an Above Average Lawn...

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Keys to Sustainable Lawn Care in Nebraska

Bill Kreuser

http://turf.unl.edu/

What is Sustainable Lawn Care?

• No inputs

– Lawns can’t exist without some maintenance

• Organic products and fertilizers

– Possible but know definition of “organic” in industry

– Not always better/safer/legal

• Minimizing inputs

– Less fertilizer/water/pesticides

– Changing expectations……

ExpectationsLawns Require A Lot of Energy

• Physical Energy

• Chemical Energy– Gasoline for equipment

– Manufacture of pesticides and fertilizer

– Energy to pump water

Lawns are great carbon banks

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What is Thatch?

Slowly Decaying Plant Tissues

• Stems

• Dead crowns

• Leaf Sheaths

Not clippings and roots

Highly Lignified Tissue

Why is Thatch a Problem

• Turfgrass crowns are exposed to elements

• Harbor pests

• Reduced water infiltration

• Easy to scalp during mowing

• Nothing good about TOO much thatch

Keys to Sustainable Best Management Practices for an Above Average Lawn

1. Plant the correct grass/plant

2. Mow correctly

3. Precisely manage water and nutrient applications

4. Manage soil

5. Use pesticides as last resort!

Plant the Correct Grass

• Mostly cool-season turf in NE

– Creeping: Kentucky bluegrass

– Bunch type: Tall fescue, perennial ryegrass

• Warm season exception

– Buffalograss

• Native to the Great Plains

• Creeping type grass

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Kentucky bluegrass• Fine leaf texture and mid to

dark green color

• Spreads by lateral stems in the soil called rhizomes

• Average root system and water use (ET)

• Goes dormant during drought

• Good for cool/arid climates (Western NE)

Common Kentucky Bluegrass

Elite/Improved Kentucky Bluegrass Premium Kentucky Bluegrass

0 Fert Apps 4 Fert Apps

3.5 Inch HOC

2.5 inch HOC

Turf Type Tall Fescue• Dark green color with course

to medium-fine texture

• Good heat tolerance

• Deep rooting turf but highest water use

• Great for locations with temporary (short-term) drought

• Eastern NE, but exploring suitability in further west

Tall Fescue

4 Fert Apps 0 Fert Apps 2 Fert Apps

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Perennial Ryegrass

• Fine texture and shiny dark green leaf

• Quick to establish

• Poor to moderate drought tolerance and avoidance

• Susceptible to summer diseases/insects

• Killed by extreme temperatures

Perennial Ryegrass

0 Fert Apps 4 Fert Apps 2 Fert Apps

Buffalograss

• Native to Great Plains

• Light green color and fine texture

• Warm-season grass (grows during summer

• Deep rooting + low water use

• Low (not no) maintenance

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Sometimes Grass isn’t the Anwser

Questions



2. Mow correctly


4. Manage soil


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Benefits of Mowing

• Appearance

• Increase leaf density

• Remove damaged leaves

• Prevents seed heads from forming

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Does Mowing Height and Frequency Affect Growth Rate

Different Rationales:

1) Frequent mowing increases turfgrass growth rate because it is less stressful than scalping

2) Scalping cause the growth to grow slower and reduces mowing requirements

3) Mowing to the 1/3 rule is best for healthy turf while providing the minimal amounts of mowing

Designed a Tall Fescue Mowing StudyTreatments:

• Height of cut (2” or 3”)

• Frequency of Cut (weekly, ¼ rule, 1/3 rule, ½ rule)

Controls

• Never fertilized during the year and watered to 80% of pET nightly

Measured clipping yield and turf quality all summer

Explaining Mowing Frequencies

2" 3"

Weekly - -

1/4 Rule 2.66 4

1/3 Rule 3 4.5

1/2 Rule 4 6

3”½ Rule Weekly ¼ Rule 1/3 Rule

block 1

2”½ Rule Weekly ¼ Rule 1/3 Rule

2”¼ Rule Weekly 1/3 Rule ½ Rule

block 2

3”¼ Rule Weekly 1/3 Rule ½ Rule

2”½ Rule 1/3 Rule Weekly ¼ Rule

block 3

3”½ Rule 1/3 Rule Weekly ¼ Rule

At End of Season, Mowed All Plots to 2” or 3” and calculated total clipping

production

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First Year Results

No ScalpingGood Quality

No ScalpingGood Quality

Cumulative Clippings Over Time

Mowing Best Management Practices

• Mow at 2 to 3 inches

– Higher to keep out weeds

– Reduced water use

• Mow to 1/3 rule: 3 to 4.5 inches

– Reduces number of total mowings

– Keeps turf healthy and dense

– Doesn’t scalp the turf

• Return clippings!

Questions



2. Mow correctly


4. Manage soil


Why do we water?

2% for Metabolism

98% for Cooling

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Large Differences in Annual Precip

Annual Precip < Water Loss All Plants Resist Drought Stress

Drought Avoidance Drought Tolerance

Plant Response to Drought

• Stomata Close

• Leaf growth slows

• Root growth increases

• Cell division slows

• Cells accumulate sugars

• Leaves and roots die

• Cells break/die

• Plant dies

Short Drought

Prolonged Drought

Minutes

Days

Weeks

Months

Season

Turf Needs Water

• Precision Water Management Key

–Know How Much is Required

–Monitor Soil Moisture

–Proper Placement

–Uniformity in Soil

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Irrigation Basics

• Amount and frequency change throughout the growing season

Under-Irrigation

Wilt

Insufficient Rootzone Moisture(under-watering)

• Slow growth (recuperative potential)

• Wilt

• Hard surface

• Susceptible to insect pests

Brown patch

Thatch accumulation

Excessive Irrigation

Excessive Irrigation

Algae / moss

Poa annua

• Leaching

• Anerobic soil

• Shallow rooting

• Denitrification

• Thatch accumulation

• Algae

• Moss

• Black layer

• Poor stress tolerance

• Poor quality playing surface (rutting, divoting)

• Poor shear strength

• Disease (pythium blight, brown patch, etc…)

• Waste of water ($$$$$)

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How much water is lost?• Evapotranspiration (ET) is the amount of water

lost from soil evaporation and transpiration

– Parameters?

• Directly measure ET

• Estimate potential ET

– Satellite data

http://www.hprcc.unl.edu/awdn/maps

Don’t Water to 100% pET

• Crop coefficients (Kc) available for turf

– Cool-season turf 60 to 80% of pET

– Warm-season 40 to 60% pET

– Can be much lower…

• Deficit Irrigation works when there is occasional rain

Homeowner Irrigation BMP

Turn off the irrigation systems

When you see drought symptoms then turn on the

irrigation

Apply an inch of water

Turn System Back Off

Monitor Soil Moisture

TDR Probe

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0

10

20

30

40

50

60

70

80

June July August September

TN

C i

n t

urf

gra

ss r

oo

ts(m

g g

-1)

Light & frequent

Deep & infrequent

Moderate Drought Stress Increases Plant Health

Fu, J., and P. H. Dernoeden. 2008. Carbohydrate metabolism in creeping bentgrass as influenced by two summer irrigation

practices. J. Am. Soc. Hortic. Sci. 133(5):p. 678-683.

Deficit Irrigation

• Keeps things consistently dry

• Uses less irrigation

• Reduces nutrient and pesticides leaching

• Requires closer monitoring

Optimize irrigation applications

• Check your systems

– Nozzle wear and uneven heads

– Minutes vs inches

• Monitor soil moisture

• Adjust run times and change nozzles

• Recognize wilt and then water

Irrigation Distribution Uniformity

Minutes vs. Inches

There is no universal amount of water to apply

Questions

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Why Fertilize Turf?

• Qualitative Reasons

– Color

– Leaf density

– Recover from traffic

– Recover from environmental stress

• Replace nutrients as they become unavailable

– Leaching, volatilization, runoff, removal

– Fixation and Immobilization

The Essential Nutrients

Primary & Secondary

• Nitrogen (N)

• Phosphorus (P)

• Potassium (K)

% N - % P2O5 - % K2O

• Calcium (Ca)

• Magnesium (Mg)

• Sulfur (S)

Micronutrients

• Iron (Fe)

• Manganese (Mn)

• Molybdenum (Mo)

• Zinc (Zn)

• Boron (B)

• Chlorine (Cl)

• Copper (Cu)

• Nickel (Ni)

Silicon???

All Nutrients Are Important

• Turfgrass growth controlled by the most limiting nutrient

• Nitrogen almost always the limiting nutrient

Nitro

gen

We Don’t Maximize Yield Like a Crop

0

50

100

150

200

250

300

350

400

450

0 2 4 6 8 10 12 14 16

Cli

pp

ings

lb/M

N Rate lb/M/yr

Low N High N

How Much Nitrogen to Apply?

• Yield unimportant

• Depends on turfgrass application

– Performance

– Quality

• Current recommendations are historical

Goldilocks Method

Too much Nitrogen

• Reduced root growth

– Decreases stress tolerance - esp. water

• Excessive thatch development

• Increased mowing requirement

• Increases incidence of many diseases

– brown patch, snow mold, gray leaf spot, take-all patch

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Not Enough Nitrogen

• Reduced shoot density– Increased weed invasion – esp. clover and

crabgrass

– Increased reliance on pesticides

– May need to completely renovate if weeds win

• Unsafe playing conditions

• Unattractive

• Increases incidence of certain diseases– Rust, red thread, dollar spot

Just Right Nitrogen

• Good green color

• Moderate growth rate

• Optimum tolerance to environmental stresses

• High shoot density but vigorous root system

• Good recuperative potential

• Poor turfgrass performance (putting greens)

Turfgrass N Cycle

Mineral Nitrogen (NH4

+, NO3-, NO2

-)Organic Nitrogen Complex structure

Immobilization(Plant & Microbe Uptake)

Mineralization

Microbe DependentLeaching & Runoff

Denitrification & Volatilization

Clipping Removal &

Aeration

AtmosphericDepositionFixation

Fertilizer

OM accumulates as turf ages

Source: Gaussoin and Shearman, 2003; Gaussoin et al., 2006

Soil OM increases with time – Adds fertility

Qian et al., 2003

N uptake from fert (~1#/M)

N uptake from soil (~1#/M)

N uptake from clippings (~1#/M)

From a well established lawn area

Starr and DeRoo, 1981

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Slow SOM build-up reduces N requirements

Frank et al., 2006

MSU Monmouth Lysimeters

Nitrogen leaching from over-fertilizing established turfNitrogen Fertilization BMPS

• Amount of N required changes as turf ages

– New lawn

• 2-6 applications a year

– Established lawn

• 0-3 applications a year

– Kentucky bluegrass and perennial ryegrass need more than tall fescue or buffalograss

• Timing critical

Average Fertility Requirements

Grass Species Average Lawn High Maintenance

lbs N/1000 ft2

Kentuckybluegrass

1-4* 2-6

Perennial ryegrass

2-5 2-6

Tall fescue 0-2 2-4

Fine fescue 0-2 1-3

Buffalograss 0-2 0-2

When to apply fertilizer• Cool-season turf

1. Late summer (Aug-September)

• Balanced N source (50% WSN 50% WISN)

2. Mid-spring (Late April)

• After initial spring growth surge (balanced source)

3. Mid-summer (June)

• Slow release or organic nitrogen (WISN)

• Water in and don’t apply to drought stress turf

4. Mid-fall (mid-October)

1. Quick release (WSN)

2. Not too late….recommendation has changed

When to apply fertilizer• Warm-season turf

1. Early summer (May to June)

2. Mid-summer (July to early Aug)

• Balanced nitrogen source

• Water in and be careful during drought periods

Soil Test for Other Essential Nutrients

• Estimate plant available nutrients

• Monitor changes in soil nutrients

• Peace of Mind

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-

-

-- -

--

--

-

--

-

--

-

-

Mg2+

H+

K+

Cation Exchange Capacity

Ca2+ We Can Test for Everything but N

Primary & Secondary

• Nitrogen (N)

• Phosphorus (P)

• Potassium (K)

• Calcium (Ca)

• Magnesium (Mg)

• Sulfur (S)

Micronutrients

• Iron (Fe)

• Manganese (Mn)

• Molybdenum (Mo)

• Zinc (Zn)

• Boron (B)

• Chlorine (Cl)

• Copper (Cu)

• Nickel (Ni)

Proper Sampling Collecting a Representative Sample• Take a Composite

Representative Sample

• Consistent Sampling Depth and Time of Year

• Consistent Soil Testing Lab or Method

Proper Sampling

• Representative Areas–Mineral soils vs. sand or constructed soils

–Areas built at different times

–Areas cut out of forest vs. old agricultural land

–Areas of drastically different soil type

Where the roots are

How Deep?

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How Deep?

DepthMehlich 3

Phosphorus

Inches ppm

0 – 1 205

0 – 2 138

0 – 6 74

33% decrease in

soil P with addition

of 1 inch of soil!

Keys to Consistent Soil Testing

When: Early Spring

Where: Representative soil areas

How Deep: Be consistent, 4” good depth

Which Lab: Use same lab you trust always

Micronutrients: Who cares – tissue testing best

Need to be consistent to monitor changes over time!!

Great Fertilizer Grade Diversity

Blended Fertilizers

• Mixture of fertilizer sources

– Nutrient release character release

– Addition of other nutrients

• Suited to address different turf requirements

– Starter (high P2O5)

– Winterizer (higher K2O)

– Micronutrients additions

• What’s the ideal fertilizer ratio for turfgrass?

Plants Control Nutrient Uptake NotTurf Managers

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Fertilizing Soils With Sufficient Nutrients Does Not Affect Turf

4.3 4.3 4.3 4.3

0.44 0.44 0.42 0.43

2.5 2.6 2.6 2.6

0

1

2

3

4

5

4-0-0 4-1-0 4-0-3 4-1-3

Tiss

ue

Co

nte

nt

(% d

ry w

eig

ht)

Pounds of N-P2O5-K2O Fertilizer Applied Annually to 1000 ft2

Leaf N

Leaf P

Leaf K

62ppm Soil Test Phosphorus 180ppm Soil Test Potassium

N drives uptake of other nutrients

3.8

4.3

5.2

0.42 0.44 0.48

2.42.6

2.9

0

1

2

3

4

5

6

2 4 6

Tiss

ue

Co

nte

nt

(% d

ry w

eig

ht)

Annual Nitrogen Fertilization Rate (lbs/1000 ft2)

Leaf N

Leaf P

Leaf K

Fertilizer Ratio: 5-1-2Soil Test P: 62ppmSoil Test K: 180ppm

1-0-0 – The Ideal Fertilizer Ratio?

• Nitrogen-only fertilization can be very effective

• Gradual decline in other soil test nutrients levels with N only fertilization

• Treat the soil like a nutrient bank account

Nutrient Losses = Fertilizer Additions

5-1-2 Ratio Changed Soil Test Levels

6

10

17

25

37

57

0

10

20

30

40

50

60

2 4 6

Ch

ange

in S

oil

Test

Lev

els

(Th

ree

Year

s p

pm

)

Annual Nitrogen Fertilization Rate (lbs/1000 ft2)

Soil Test P

Soil Test K

Fertilizer Ratio: 5-1-2Soil Test P: 62ppmSoil Test K: 180ppm

Approximate* Ideal Fertilization Ratios

Grass Species Root Zone Soil Mowing Clipping

Management

Annual Ideal

Fertilizer Ratio

Cool-season lawn and

athletic field species

(Kentucky bluegrass,

perennial ryegrass)

Native soil Clippings Removed 4-1-3

Clippings Returned 8-1-4

Sand-based soil Clippings Removed 4-1-4


Creeping bentgrass

turf

Native soil Clippings Removed 4-1-3


Sand-based soil Clippings Removed 4-1-4


* Actual ideal fertilizer ratio varies depending on local environment (soil, precip, ect.)

Questions??

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2. Mow correctly


4. Manage soil


What is Thatch?

Slowly Decaying Plant Tissues

• Stems

• Dead crowns

• Leaf Sheaths

Not clippings and roots

Highly Lignified Tissue

Thatch Management Strategies

• Species Selection

• Nitrogen Fertilization

• Mechanical Removal

• Renovation

pH modification, avoid pesticides, inoculate with

microbes

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Differences in Species and Variety

Higher Thatch Potential

• Kentucky bluegrass

• Fine fescue

• Roughstalk bluegrass

• Improved varieties

Lower Thatch Potential

• Perennial ryegrass

• Tall fescue

• Older common varieties

Implications for Management

Mechanical RemovalCore Aeration Dethatcher – Power Rake

Manual Raking Fun

Aeration Impact Tine Size and Surface Area Chart

Tine Size

(in.)

Spacing

(in.)

Holes/ft2

Surface

Area

of One

Tine

Percent

Surface

Area

Affected

1/4 1.252 100 0.049 3.4%

1/4 2.52 25 0.049 0.9%

1/2 1.252 100 0.196 13.6%

1/2 2.52 25 0.196 3.4%

5/8 2.52 25 3.07 5.3%

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Still Benefits to Aeration

• Increased water infiltration

• Cores dilute some thatch as topdressing

• Increased soil aeration

• Reduced soil compaction

Timing Thatch Removal

Avoid Early Spring, Mid-Summer, and Late Fall Power Raking

Dilution Can Be the Solution

• Topdressing buries thatch

• Enhances microbial breakdown

• Materials

– Sand

– Compost

Extreme Thatch Accumulation Call for Complete Renovation Turf.unl.edu

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Best Management Practices for an Above Average Lawn in Central NE

1. Plant Tall Fescue or Buffalograss

2. Mow grass to 3” when it reaches 4.5”

3. Water deeply when drought stress is visible

4. Fertilize when grass looks yellow (late spring and early fall)

5. Manage water and fertilizer to limit thatch; remove in spring


Bill [email protected]://turf.unl.edu/

mailto:[email protected]

http://turf.unl.edu/

What is Sustainable Lawn Care? Keys to Sustainable Lawn ... · Practices for an Above Average Lawn...

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