Fertilizer Task Force

Dr. Terril NellUF/IFAS Environmental Horticulture Dept.(352) 392-1831, tanell@ufl.edu

Current UF Guidelines for Annual TurfgrassFertilization Rates

Species Location Annual N Rate (lbs. N 1,000 ft-2)

Bahiagrass North 2-3Central 2-4South 2-4

Bermudagrass North 3-5Central 4-6South 5-7

Centipedegrass North 1-2Central 2-3South 2-3

St. Augustinegrass North 2-4Central 2-5South 4-6

Zoysiagrass North 3-5Central 3-6South 4-6

Statewide Fertilizer Guidelines These were developed with all pertinent turf faculty in

2000-2001 at request of Dean Dusky Developed as interim recommendations until research

indicates a need for change The collective faculty felt that these rates would provide

for strong healthy turf without negative environmental impacts

Allow for homeowner (do-it-yourselfers) and professional applications

Do not cover nutritional requirements of athletic fields or golf courses

Statewide Fertilizer Guidelines These guidelines only recommend N application

rates Other nutrient requirements (primarily P) should

be based on soil or tissue tests Potassium generally applied at a ratio of 2:1 N:K

or 1:1 N:K Based on professional preferences/experiences or what

analysis fertilizer consumer happens to buy Other macronutrients seldom limiting in turf in FL In high pH soils, recommend application of soluble

Fe and Mn

Data for DACS Fertilizer Rule Nitrogen data based on best available

information and consensus of all parties involved

Phosphorus data based on calculations done by Dr. Sartain relating to St. Augustinegrass P nutritional requirements

Sustainability

Nutritional maintenance program designed to sustain turf health and growth under both optimal and stress (disease, pest, drought, traffic, salinity, etc.) conditions, where inputs will not cause environmental impacts

Run Off Issues

Research has shown that during grow-in, less than 0.03% of applied N was collected as run-off on a 10% slope in bermudagrass

Shaddox and Sartain, 2005, Proc Fl Soil and Crop

Buffer Zone Around Water Bodies No research base currently for establishment of

buffer zone Many propose large untreated areas, but these

may actually contribute to increased NPSP Larger buffer zones may contribute to NPSP due

to loss of turf stand, increased stormwater runoff, and soil erosion

Area of needed research

Model Ordinance

FDEP publication (2002) with input from UF, WMDs, environmental organizations, FFAA, pest control industries, and other stakeholders

Designed to be a template for local governments to use when considering landscape ordinances

BMP Educational Program Development FDEP program that is delivered by IFAS Designed to train landscape and pest control industries how to

do their jobs without causing pollution Program began in 2002 Dr. Trenholm is grant PI and lead trainer is this program-

offered at IFAS County Extension offices statewide Approximately 2,300 people trained in statewide training

sessions to date Others (~100) have been trained on-line at greenindustries.org FDEP has invested approximately $700,000 in this program to

date

BMP Educational Program Development Program now offered in both English and

Spanish (at certain locations only at this time) Currently development of the “Train the Trainer”

program is underway This program is a requirement in most

city/county ordinances DACS is currently planning to include some or

all of this program in the L&O licensing exam

BMP Development and Fertilizer Issues Annual fertilizer rate guidelines used in BMP

educational program Rates for each application limited to:

0.5 lbs. N per 1,000 ft-2 for quick-release sources* 1.0 lbs. N per 1,000 ft-2 for slow-release sources

Nitrogen sources discussed in BMPs, but no recommendation of one over another – when properly applied, turf has excellent ability to take up all N sources

* Differs from DACS Fertilizer Rule

Nutrient Leaching Research

Current FDEP funded project: 5-6 year 3 locations statewide Quantifying nutrient leaching in lawn grasses under a wide

variety of circumstances Nitrogen rates Nitrogen sources (to start 08 or 09) Winter fertility Establishment fertility Soil type Phosphorus requirement and leachability

Nutrient Leaching Research

Preliminary data collected do not meet FDEP quality assurance requirements because of prolonged storage prior to analysis

FDEP and IFAS are working towards recovering most of the data by developing correction curves

Lysimeters buried in center of each plot

As nitrate percolates downward through the column, it collects in reservoir filled with gravel. At bottom of lysimeter is a portal for tubing that runs to collection device aboveground. To collect leachate, a vacuum pump is attached the the tubing and water evacuated from base. A sub-sample is collected for analysis.

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

Total N Leached

0.5 lbs N

1.0 lbs N

2.0 lbs N

Total Annual N Leached During

Establishment of Empire Zoysiagrass in 2005N

(m

g M

2 )

a

a a

Trenholm, 2005

Percent of Applied N Leached from

Empire Zoysiagrass in 2005

0

20

40

60

80

100

120

140

0.5 lbs. N

1.0 lbs. N

2.0 lbs. N

Percent of Applied N Leached

% N

a ab

b

Trenholm, 2005

Total Annual N Leached in Established Empire and Floratam in 2005

0

100

200

300

400

500

600

700

800

900

1000

0.6 lbs N

1.3 lbs N

2.6 lbs N

4 lbs N

N (

mg

M2)

Total N Leached

a a a a

Trenholm, 2005

Percent of Applied N Leached from Established

Empire and Floratam in 2005

0

2

4

6

8

10

12

14

16

18

0.6 lbs N

1.3 lbs N

2.6 lbs N

4.0 lbs N

Percent of Applied N Leached

% N

a ab cbc

Trenholm, 2005

Other Turf Nutrient Leaching Research

Work done by Dr. Jerry Sartain

LEACHING N LOSS FROM SLOW-RELEASE N SOURCES

80

62 5850

2817

AS CAS NUT SCU NIT IBDU

NITROGEN SOURCES

0

20

40

60

80

100

% N

LE

AC

HE

D

PERCENTAGE OF APPLIED N LEACHEDFROM RYEGRASS(2 LBS N/1000 SQ FT/125 d)

12.8

8.17.2

2.9 2.8 2.81.1 0.4

ASUAN

CORONNUTRALENE

POLYONSCU

IBDUNITROFORM

NITROGEN SOURCE

0

2

4

6

8

10

12

14

PE

RC

EN

TAG

E O

F A

PP

LIE

D N

LE

AC

HE

D (

%)

A B B C C C D E

EFFECT ON N SOURCE ON % N RECOVEREDDURING FLORADWARF MAINTENANCE PHASE

52.7

0.54.3

57.8

47.3

0.1

7

54.456

2.6 4.7

63.2

UPTAKE LEACHED SOIL % RECOVERED

RECOVERED PARTITION

0

10

20

30

40

50

60

70

PE

RC

EN

TAG

E O

F A

PP

LIE

D (

%)

AN AN + MIL AN + MIL + IBDU

Effect of N Source on % N Recovered in Leachate

in Established FloraDwarf Bermudagrass

CUMMULATIVE TOTAL N LEACHED AS UREA, NH4 AND NO3

1409

1076

521

284

1513

858

CAS NUT NIT IBDU AS SCU

NITROGEN SOURCE

0

200

400

600

800

1000

1200

1400

1600

1800

TO

TAL

N L

EA

CH

ED

(m

g)

UREA

NH4

NO3

Environmental Impact

Research Needed Buffer zone fertilization for minimizing environmental

impacts (slope, soil type) Nutrient uptake and losses from blended vs.

homogenous fertilizers Long-term effects of nutrient deprivation during rainy

seasons on turfgrass growth and health Comparative N and P losses of turf relative to

ornamentals and shrubs Relationship of landscape and turf fertilization and

red tide

Integrated Approach

Center for Landscape Conservation and EcologyTurfgrass and Landscape FacultyGrant Opportunities