trends in turf nutrition: overview · recommendation range for centipedegrass in north florida do...
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![Page 1: Trends in Turf Nutrition: Overview · recommendation range for centipedegrass in north Florida do not pose an increased risk to NO3‐N leaching. – However, they also indicate that](https://reader033.vdocument.in/reader033/viewer/2022050511/5f9becb204b38228337a08f7/html5/thumbnails/1.jpg)
Dr. J. Bryan Unruh
Extension Turfgrass Specialist
University of Florida/IFAS
Trends in Turf Nutrition:Balancing Environmental Protection and Turf Performance
Overview
• Fertilizer License Requirement
• Urban Turf Rule Revision
• Sticking to the UF/IFAS Recommendations
• Does the Soil Test Lie?
• Fertilizing Damaged Turf
•2
Overview
• Fertilizer License Requirement
• Urban Turf Rule Revision
• Sticking to the UF/IFAS Recommendations
• Does the Soil Test Lie?
• Fertilizing Damaged Turf
•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
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BMPs are a Starting PointEmployment Classification* 2011 2012 2013 2014
Pesticide: Handlers, Sprayers, and Applicators, Vegetation
3,070 3,280 2,630 3,190
**Landscaping and GroundskeepingWorkers
69,040 70,540 70,750 74,200
Grounds Maintenance Workers and All Other
1,030 1,140 1,110 1,050
Total 73,140 74,960 74,490 78,440
*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
0
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
2006 2007 2008 2009 2010 2011 2012 2013 2014 2015
GI-BMP TrainingJan. 1, 2006 - May 1, 2015
In-person Online
DVD Equivalent
35,107 since 2006
Overview
• Fertilizer License Requirement
• Urban Turf Rule Revision
• Sticking to the UF/IFAS Recommendations
• Does the Soil Test Lie?
• Fertilizing Damaged Turf
•10
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.
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2/1/2009 4/1/2009 6/1/2009 8/1/2009 10/1/2009 12/1/2009
Tot
al N
O3 Le
ache
d (k
g 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 north Florida!
– UF only recommends the 2.0 lb rate in those regions of Florida that have summertime fertilizer blackout ordinances.
14
2015 Statewide Fertilizer Rule
• Keep a watchful eye out for those who may propose a blackout in north Florida.
– UF Recommendation: no fertilizer prior to April 15 and none after mid‐September.
– Blackouts: May through September
15
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Two week window to fertilize!
Overview
• Fertilizer License Requirement
• Urban Turf Rule Revision
• Sticking to the UF/IFAS Recommendations
• Does the Soil Test Lie?
• Fertilizing Damaged Turf
•16
17
How much nitrogen do the turfgrasses need on a monthly basis?
Bahiagrass
Bermudagrass
Centipedegrass
St. Augustinegrass
Zosyiagrass
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JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Pe
rcen
t G
row
th P
ote
ntia
l
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
21 22
Nitrogen Rate (kg N ha-1 yr-1)
0 20 40 60 80 100 120 140 160
Turf Q
uality
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
23
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 for 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.
25
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.
26
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
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.
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
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Overview
• Fertilizer License Requirement
• Urban Turf Rule Revision
• Sticking to the UF/IFAS Recommendations
• Does the Soil Test Lie?
• Fertilizing Damaged Turf
•31
Front Yard – Struggling to Survive
32
Back Yard – Not too Bad
33 34
35
Front Yard Back Yard
Soil Tests (Generally) Don’t Lie
• One size does not fit all!
• If the corrective actions aren’t working – dig deeper.
– Call in the guns!
• Take samples properly and report to the lab pertinent information!
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68’
37’
Area = (l) (w)Area = (37 ft) (68 ft)Area = 2,516 ft²
We apply fertilizer to a two‐dimensional soil surface (length X width = area).
Soil Sampling & Testing
• But soil tests are three dimensional (length X width X depth).
– One pound of an element (N, P, K, etc.) spread over 1,000 ft2 on the surface (two dimensional) is equivalent to:
• 22 ppm in the root zone (three dimensional) measuring 1,000 ft2 to a 6” depth.
• 33 ppm in the root zone (three dimensional) measuring 1,000 ft2 to a 4” depth.
38
It’s early – but let’s do some math! It’s early – but let’s do some math!
Overview
• Fertilizer License Requirement
• Urban Turf Rule Revision
• Sticking to the UF/IFAS Recommendations
• Does the Soil Test Lie?
• Fertilizing Damaged Turf
41
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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43
Winterkill on Centipedegrass
44
Take‐all Root Rot on St. Augustinegrass
Winterkill on St. Augustinegrass
45
Herbicide Injury on Zoysiagrass46
Dinitroaniline Herbicide Injury47 48
Dinitroaniline Herbicide Injury+
Shade and Over‐watering
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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
Tur
f D
ensi
ty (1-9
; 6 m
inim
um a
ccept
able
)
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
Tota
l NO
3 L
each
ed (kg
ha
-1)
0
2
4
6
8
10
12
14
16
Rain
(m
m)
0
10
20
30
40
50
60
Arrow denotes fertilizer application date.
SR Nitrogen Source Study – Jay, FL
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
Actua l rainfa l 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 Zoysiagrass52
Nitrogen Rate Study – Floratam / Empire
53
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?
55
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. 56
Extensive Large Patch Injury
• Estimated ~80% damage
• Uniform injury/coverage
• Recommendation: RoundUp and resod!57
Large Patch Damage
• Estimated ~15% damage
• Non‐uniform injury/coverage
• Recommendation:– Treat for the disease.
– Avoid fertilizing damaged site.
58
Extensive Take‐all Root Rot
• Estimated ~30% turf ground cover
• Non‐uniform injury/coverage
• Recommendation: Resod the damaged area.
59
Non‐Selective Herbicide Applied to Non‐Dormant Turf
• Estimated ~50% turf ground cover
• Non‐uniform injury/coverage
• Recommendation: Wait for possible recovery.– Do NOT fertilizer until turf is completely recovered.
60
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Selective Herbicide Injury
• Estimated ~80% turf ground cover
• Non‐uniform injury/coverage
• 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.
61
Overview
• Fertilizer License Requirement
• Urban Turf Rule Revision
• Sticking to the UF/IFAS Recommendations
• Does the Soil Test Lie?
• Fertilizing Damaged Turf
•62
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