florida fertilization overview - uf/ifa · – uf only recommends the 2.0 lb rate in those regions...

Dr. J. Bryan Unruh

Extension Turfgrass Specialist

University of Florida/IFAS

North Florida Fertilization Strategies that Promote Healthy Turf

Overview

• Fertilizer License Requirement

• Urban Turf Rule Revision

• Sticking to the UF/IFAS Recommendations

• Fertilizing Damaged Turf

2

Overview





3

The axe has fallen. . .• Beginning January 2014, ALL commercial fertilizer applicators MUST BE certified by FDACS in order to make ANY TYPE of fertilizer application to:– Commercial turf or ornamental areas;– Turf or ornamental areas of parks or fields (other than agricultural areas);

– Turf or ornamental area of any residential property.

• Prior to issuance of this certification, the applicator MUST PROVIDE proof of having received training in "Green Industry Best Management Practices“ taught by UF/IFAS.

The axe has fallen. . .

“You must enclose a certificate of completion of training issued by the University of Florida (IFAS) and/or Department ofEnvironmental Protection (DEP) with this application.”

GI‐BMP Training Options

BMPs are a Starting PointEmployment Classification* 2010 2011 2012 2013

Pesticide: Handlers, Sprayers, and Applicators, Vegetation

2,890 3,070 3,280 2,630

**Landscaping and GroundskeepingWorkers

73,090 69,040 70,540 70,750

Grounds Maintenance Workers and All Other

630 1,030 1,140 1,110

Total 76,610 73,140 74,960 74,490

*Estimates are based on Standard Occupational Classification Codes. http://www.floridajobs.org/labor-market-information/data-center/statistical-programs/occupational-employment-statistics-and-wages

**Landscape or maintain grounds of property using hand or power tools or equipment. Workers typically perform a variety of tasks, which may include any combination of the following: sod laying, mowing, trimming, planting, watering, fertilizing, digging, raking, sprinkler installation, and installation of mortarless segmental concrete masonry wall units. Exclude "Farmworkers and Laborers, Crop, Nursery, and Greenhouse" (45-2092).

BMPs are a Starting Point Overview





10

Pre‐2015 Statewide Fertilizer Rule(a.k.a Urban Turf Rule)

• Limits N to 1 lb per 1,000 ft2 maximum application rate or 0.7 lb per 1,000 ft2 for quick‐release N

• Limits P to 1/4 lb P2O5 per 1,000 ft2 per

application and 1/2 lb P2O5 per 1,000 ft2

annually

• Annual N rates follow UF recommendations

• Requires lawn care industry to follow Green Industries BMP manual

2015 Statewide Fertilizer Rule(a.k.a Urban Turf Rule)

• “Actively Growing” means turf that needs mowing at least every two weeks.

• Nitrogen shall not be applied at an application rate greater than 0.7 lbs of readily available nitrogen, per 1000 sq. ft. per application at any one time based on the soluble fraction of formulated fertilizer.

2015 Statewide Fertilizer Rule(a.k.a Urban Turf Rule)

• Not more than 2 lbs. of total nitrogen per 1000 sq. ft. per application may be applied during the spring or early summer;

• Not more than 1 lb total nitrogen per 1000 sq. ft. per application may be applied during the fall or winter.

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

2015 Statewide Fertilizer Rule

• No major impact in northwest Florida!

– UF only recommends the 2.0 lb rate in those regions of Florida that have summertime fertilizer blackout ordinances.

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2015 Statewide Fertilizer Rule

• Keep a watchful eye out for those who may propose a blackout in northwest Florida.

– UF Recommendation: no fertilizer prior to April 15 and not after mid‐September.

– Blackouts: May through September

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

Two week window to fertilize!

Overview





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UF/IFAS Recommendations

Table 1. Fertilization Guidelines for Established Turfgrass Lawns

Nitrogen Recommendations (lbs 1,000 ft‐2 year‐1)1, 2

North Florida

Bahiagrass 2.0 – 3.0

Bermudagrass 3.0 – 5.0

Centipedegrass 1.0 – 2.0

St. Augustinegrass 2.0 – 4.0

Zoysiagrass 2.0 – 3.0

1Because homeowner preferences for lawn quality and maintenance level will vary; we recommend a range of fertility rates for each

grass and location. Additionally, effects within a localized region (i.e., micro‐environmental influences ‐‐ such as shade, drought, soil

conditions, and irrigation) will necessitate that a range of fertility rates be used.

2These recommendations assume that grass clippings are left on the lawn.

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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

How much nitrogen do the turfgrasses need on a monthly basis?

Bahiagrass

Bermudagrass

Centipedegrass

St. Augustinegrass

Zosyiagrass

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Pensacola, FL Mobile, AL Desin, FL Panama City, FL

lbs N 1,000 ft2

JAN 0.01 0.00 0.01 0.01FEB 0.01 0.01 0.01 0.01MAR 0.04 0.03 0.04 0.05APR 0.11 0.10 0.11 0.12MAY 0.27 0.26 0.27 0.28JUN 0.41 0.40 0.42 0.40JUL 0.45 0.44 0.46 0.44AUG 0.44 0.43 0.45 0.44SEP 0.37 0.34 0.38 0.38OCT 0.15 0.13 0.18 0.18NOV 0.04 0.03 0.05 0.05DEC 0.01 0.01 0.01 0.01

2.31 2.18 2.39 2.38


lbs N 1,000 ft2


3.47 3.27 3.59 3.57


lbs N 1,000 ft2


4.62 4.35 4.78 4.76

Nitrogen Rate (kg N ha-1 yr-1)

0 20 40 60 80 100 120 140 160

Tur

f Qua

lity

1

6

7

8

9

2006 y=6.63+0.0145x-0.000021x2; R2=0.99*

2007 y=5.93+0.0186x-0.000025x2; R2=0.99*

Centipedegrass

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1.0 lb 2.0 lb

Centipedegrass

• Our results indicate the current UF N recommendation range for centipedegrass in north Florida do not pose an increased risk to NO3‐N leaching.– However, they also indicate that the lowest recommended rate of 1 lb N 1,000 ft‐2 per year may provide more N than is necessary to produce acceptable centipedegrass.

– A rate of 0.75 lb N 1,000 ft‐2 per year would likely produce acceptable quality turfgrass during the entire season and produce little risk to NO3‐N leaching.

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Bahiagrass

• Current N recommendations to bahiagrass in south Florida are higher than is necessary to produce acceptable turf by home‐lawn standards.

• The 1 lb N 1,000 ft‐2 led to acceptable turf quality during each cycle while regression analysis indicated quality could be achieved without addition of N.

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C.

Nitrogen (kg ha-1 yr-1)

0 100 200 300

Gro

wth

Ra

te (

g m

-2 d

-1)

1.2

1.4

1.6

1.8

2.0

2.2

2.4

y=1.019+0.0085x-0.000015121x2

R2=0.99**

A.

0 100 200 300

Vis

ua

l Q

ua

lity

1

6

7

8

9

10

y=6.182+0.0074x-0.000013395x2

R2=0.99*

B.

0 100 200 300

Co

lor

1

6

7

8

9

10

y=6.323+0.0065x-0.0000096798x2

R2=0.98*

1.0 lb

St. Augustinegrass• Results indicate that N applied

according to the recommendations for Jay and Ft. Lauderdale produced acceptable quality turf at the low and high N range when turf was not exhibiting stress symptoms during most cycles.

• However, the minimum N required to produce acceptable turf in Citra was predicted to be 3.4 lb N 1,000 ft‐2 which represents an increase in 1.4 lb N 1,000 ft‐2 per year from the current recommended minimum.

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Ft. Lauderdale

0 100 200 300 400 500 600 700

1

6

7

8

9

10

Citra

0 100 200 300 400 500 600

Tur

f Q

ualit

y

1

5

6

7

8

9

Jay

Nitrogen Rate (kg N ha-1)

0 50 100 150 200 250 300 350

1

5

6

7

8

9

2006

2007

y = 5.87 + 0.0157x - 0.000028113x2

R2 = 0.99*

y = 4.66 +0.008x - 0.000017366x2

R2 = 0.98*

y = 5.33 + 0.0072x - 0.0000052107x2

R2 = 0.99*

y = 4.05 + 0.0144x - 0.000015758x2

R2 = 0.99*

3.4 lb

Getting a Response. . .

• Research shows that you need 0.30 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

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.

Overview





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Damaged Turf

• All fertilizer recommendations are based on having a “healthy, dense turf” that is “actively growing.”

– Damaged lawns are commonplace throughout the green industry.

• Damage can be attributed to a number of reasons.

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35

Winterkill on Centipedegrass

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Take‐all Root Rot on St. Augustinegrass

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Winterkill on Centipedegrass Winterkill on St. Augustinegrass

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Herbicide Injury on Zoysiagrass39

Dinitroaniline Herbicide Injury40

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Dinitroaniline Herbicide Injury+

Shade and Over‐watering

Nitrogen Leaching in Relation to St. Augustinegrass Turf Density in Northwest Florida ‐ 2005 – 2007

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.


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.


01‐Au

g‐08

01‐Fe

b‐09

01‐Au

g‐09

01‐Fe

b‐10

01‐Au

g‐10

01‐Fe

b‐11

01‐Au

g‐11

Total m

onthly nitrate leached

kg ha‐1

0

2

4

6

8

10

12

St. Augstinegrass

Centipedegrass

Monthly Total of NO3‐N Leached from St. Augustinegrass and Centipedegrass from 2008 – 2011

Monthy precipitation (mm)

0

100

200

300

400

Actual rainfal l

01‐Au

g‐08

01‐Fe

b‐09

01‐Au

g‐09

01‐Fe

b‐10

01‐Au

g‐10

01‐Fe

b‐11

01‐Au

g‐11

Total m

onthly nitrate leached

kg ha‐1

0

2

4

6

8

10

12

St. Augstinegrass

Centipedegrass

Nitrogen application

Import on sod Root shed?

Winter damage

Empire Zoysiagrass47

Nitrogen Rate Study – Floratam / Empire

48

Correct the Original Problems – first!

• Deteriorated turf?

– Pest damage – what caused the damage?

• Will it be prevented?

– Weed infestation – what caused this?

– Winter injury?

– Old Age?

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Factors Influencing Recovery

• Turfgrass Species

– Growth rate of the grass will dictate recovery.

– Rhizomatous grasses (with intact rhizome system) will recover more quickly.

• Stoloniferous grasses somewhat slower.

• Extent of Existing Groundcover

– Estimate the remaining level of groundcover.

• How widespread is the damage?

• How uniform is the damage?

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St. Augustinegrass Winter Injury

• Estimated ~50% damage

• Uniform injury/coverage

• Recommendation: Spoon‐feed every two weeks with 0.10 – 0.25 lbs N / 1,000 ft2 until covered and then follow standard recommendations. 51

Extensive Large Patch Injury


• Uniform injury/coverage

• Recommendation: RoundUp and resod!52

Large Patch Damage


• Non‐uniform injury/coverage

• Recommendation:– Treat for the disease.

– Avoid fertilizing damaged site.

53

Extensive Take‐all Root Rot

• Estimated ~30% turf ground cover


• Recommendation: Resod the damaged area.

54

Non‐Selective Herbicide Applied to Non‐Dormant Turf



• Recommendation: Wait for possible recovery.– Do NOT fertilizer until turf is completely recovered.

55

Selective Herbicide Injury



• Recommendation: Wait for possible recovery.– Spoon‐feed every two weeks with 0.10 – 0.25 lbsN / 1,000 ft2 until covered and then follow standard recommendations.

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Overview





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

www.facebook.com/gatorturf

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

University of Florida/[email protected]

@jbunruh

florida fertilization overview - uf/ifa · – uf only recommends the 2.0 lb rate in those regions...

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