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Practical Considerations for Minimizing Environmental Impact of Turf Nutrition

J. Bryan Unruh, Ph.D.

Extension Turf Specialist

Two Ways That Fertilizers Can Pollute

• Leaching through soil profile – this is what nitrogen will do in soils –especially sandy soils.

Two Ways That Fertilizers Can Pollute

• Surface water run‐off – this is what nitrogen and phosphorus can do.

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Clean Up Properly

• Be careful not to apply fertilizer particles onto sidewalks, roadways, or other impervious surfaces where they might wind up in the storm drain.

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200 linear feet X 5 feet wide mower = 1,000 ft2

2,000 grams clippings (dry weight)3.5% nitrogen in the clippings =

70 grams nitrogen =0.15 lbs nitrogen

16

How To Properly Apply Fertilizer

• Use a deflector shield when fertilizing near water bodies or impervious surfaces.

17

Fertilizing Around Water

“Ring of Responsibility”

Nutrient Import from Sod

• Properly harvested sod comes with ~ ½” of soil.

– Nutrients applied at the farm are likely transported with the sod.

• Irrigation during sodestablishment can beexcessive if guidelinesare not followed properly.

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• How much does a pallet of sod weigh?

• How much total N and P is contained in a pallet of sod?

PalletWeight

% Nutrient Lbs/Nutrient/Pallet

Ft2/Pallet Lbs/Nutrient/1,000 ft2

Mineral 2800 0.2 %N 5.6 450 12.4

2800 0.02 %P 0.56 450 1.24

Muck 2000 0.6 %N 12 450 26.7

2000 0.06 %P 1.2 450 2.67

Nutrient Import from Sod

Nitrate-N Leaching from Established Centipedegrass

01-May-05 01-Jun-05 01-Jul-05 01-Aug-05 01-Sep-05 01-Oct-05 01-Nov-05 01-Dec-05

To

tal N

O3 L

each

ed (

kg h

a-1)

0

1

2

3

4

5

Rai

nfa

ll (m

m)

0

20

40

60

80

100

120

140

6.13 kg/ha12.25 kg/ha24.50 kg/ha49.00 kg/ha

Arrows denote fertilizer application dates.

Sod installation

Nitrate-N Leaching from Established St. Augustinegrass

01-May-05 01-Jun-05 01-Jul-05 01-Aug-05 01-Sep-05 01-Oct-05 01-Nov-05 01-Dec-05

To

tal N

O3 L

each

ed (

kg h

a-1)

0

1

2

3

4

5

Rai

nfal

l (m

m)

0

20

40

60

80

100

120

140

16.17 kg/ha32.83 kg/ha65.17 kg/ha98.00 kg/ha

Arrows denote fertilizer application dates.

Sod installation

Impact of Fertilizer Applications to Semi-Dormant andDormant Lawn Grasses on Environmental Quality

01-Oct-06 01-Nov-06 01-Dec-06 01-Jan-07 01-Feb-07 01-Mar-07 01-Apr-07 01-May-07

Tot

al N

O3 L

each

ed (

kg h

a-1

)

0

5

10

15

20

25

0.0 kg N ha-1

6.13 kg N ha-1

12.25 kg N ha-1

24.50 kg N ha-1

49.00 kg N ha-1 Rai

n (m

m)

0

10

20

30

40

50

60

Arrows denote fertilizer application dates.

Sod installed 25-Sep-06

Nutrient Import from Sod

Nutrient Export

• In some regions of the US, waste products are being used on sod production fields with the intent of exporting nutrients into the urban environment where they will be used by the turf.

Practical Considerations• Avoid fertilization of newly laid sod for 30 – 60 days.

– Sufficient nutrients likely exist.

• Encourage sod installers/landscapers to inquire about the timing of the last farm‐applied nutrients.

– Use ranges rather than specific dates

• < 2 weeks = no fertilizer for 60 days• 2 – 4 weeks = no fertilizer for 30 – 60 days• > 4 weeks = no fertilizer for 30 days

– This could prove burdensome for less “tech‐savvy” producers.

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`

2

sdoptTobsT

21

1

e

100GP

GP = growth potentialobsT = observed temperature (F)

optT = optimum turf growth temperature (F)sd = standard deviation of the distribution

(sd warm = 12; sd cool = 10)e = natural logarithm base 2.718282…

http://www.paceturf.org/JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

Per

cen

t Gro

wth

Po

ten

tial

0

20

40

60

80

100

Pensacola Tallahassee Jacksonville Gainesville Daytona Beach Orlando Tampa Ft. Pierce Naples Ft. Lauderdale Homestead Key West

2

sdoptTobsT

21

1

e

100GP

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

Perc

ent

Gro

wth

Pote

ntia

l

0

20

40

60

80

100

Sioux City Council Bluffs Des Moines Burlington DubuqueMason City Lansing

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JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

Pe

rce

nt G

row

th P

ote

ntia

l

0

20

40

60

80

100

Sioux City Council Bluffs Des Moines Burlington DubuqueMason City Lansing

Sioux City Council Bluffs Des Moines Burlington Dubuque Mason City Lansing

lbs N 1,000 ft2

JAN 0.00 0.00 0.00 0.00 0.00 0.00 0.00FEB 0.00 0.00 0.00 0.00 0.00 0.00 0.00MAR 0.00 0.01 0.01 0.01 0.00 0.00 0.00APR 0.13 0.19 0.19 0.19 0.10 0.06 0.12MAY 0.54 0.60 0.60 0.61 0.46 0.41 0.55JUN 0.68 0.64 0.65 0.64 0.70 0.70 0.70JUL 0.57 0.48 0.50 0.48 0.65 0.66 0.62AUG 0.64 0.56 0.57 0.56 0.69 0.70 0.66SEP 0.63 0.68 0.68 0.69 0.58 0.54 0.62OCT 0.16 0.23 0.23 0.31 0.14 0.10 0.22NOV 0.00 0.01 0.01 0.02 0.01 0.00 0.01DEC 0.00 0.00 0.00 0.00 0.00 0.00 0.00

3.36 3.40 3.44 3.53 3.32 3.17 3.50

Estimating Release Properties of Slow‐Release Fertilizer Materials

Dr. Jerry Sartain

Getting a Response. . .

• Research shows that you need 0.3 lbs / 1,000 ft2 of available nitrogen to see a response in turf.

N Source 7 14 28 56 84 112 140 182

----------------------- % of Applied Nitrogen Released -----------------------

Nitroform 14 18 20 23 28 31 35 36

Nutralene 28 35 40 45 50 53 56 58

Polyon 12 23 49 75 86 90 93 94

SCU 30 50 70 84 92 95 98 99

IBDU 8 13 21 32 42 50 56 63

Osmocote 19 25 35 55 72 81 88 94

20-2-20 37 39 41 45 48 50 52 54

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8/1/2008 2/1/2009 8/1/2009 2/1/2010 8/1/2010 2/1/2011 8/1/2011

Tot

al N

O3 Leac

hed

(kg

ha

-1)

0

2

4

6

8

10

12

14

16

Pre

cent G

row

th P

otentia

l

0

20

40

60

80

100

SR Nitrogen Source Study – Jay, FL

1/1/2011 3/1/2011 5/1/2011 7/1/2011 9/1/2011

Tota

l NO

3 L

each

ed (kg

ha

-1)

0

2

4

6

8

10

12

14

16

Turf D

ensi

ty (1-9

; 6 m

inim

um

acc

epta

ble

)

0

2

4

6

8

Arrow denotes fertilizer application date.

SR Nitrogen Source Study – Jay, FL

1/1/2011 3/1/2011 5/1/2011 7/1/2011 9/1/2011

Tot

al N

O3 Le

ach

ed

(kg

ha

-1)

0

2

4

6

8

10

12

14

16

Rai

n (m

m)

0

10

20

30

40

50

60

Arrow denotes fertilizer application date.

SR Nitrogen Source Study – Jay, FL Practical Considerations

• Nutrients must be applied based on the plant’s ability to assimilate them.

– This should supersede any calendar‐based regimen.

• Healthy, dense turf is the key to minimizing environmental impact of applied nutrients.

– As the health of the plant deteriorates – one can expect problems.

Practical Considerations

• Timing of application of enhanced efficiency (SR) nutrient sources should coincide with periods of active growth potential.

– The “release period” should not extend beyond periods of active growth.

2/1/2009 4/1/2009 6/1/2009 8/1/2009 10/1/2009 12/1/2009

Tot

al N

O3 Le

ach

ed (kg

ha-1

)

0

1

2

3

4

5

Per

cent

Gro

wth

Pot

entia

l

0

20

40

60

80

100

Arrows denote fertilizer application dates.

SR Nitrogen Source Study – Jay, FL

Days30 60 90 1200

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www.gatorturf.comhttp://edis.ifas.ufl.edu

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www.facebook.com/UFTurf

J. Bryan Unruh, Ph.D.West Florida Research and Education Center

University of Florida/IFASjbu@ufl.edu