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TRANSCRIPT
Turfgrass Response to
Iron Fertilization
Travis Shaddox, Ph.D.
http://wfrec.ifas.ufl.edu/turfgrass/wp-content/uploads/sites/2/2014/10/FTGA-
Iron.pdf
Background
Most turf managers use an Fe component
in granular fertilizer
Soil test may or may not recommend
applications of Fe in Florida soils
No consideration is given to the form of Fe
Iron is an economic concern,
not environmental.
Iron is an economic concern,
not environmental.
Objective
To determine the influence of various Fe
sources on turf response
Materials and Methods
Treatments
– Untreated
– Iron Sulfate
– Iron Sucrate
– Iron Humate
– Iron Chelate (5% EDTA)
– Iron Oxide
– Iron Sulfate - Foliar
Rates
– 10 lb Fe / A
– 20 lb Fe / A
Locations
– Citra - Princess
– Jay – Tifgrand
6 weeks
Site Information
Citra
Princess Bermuda
Trts applied May 7
No prior fertilization
Soil pH 7.2
Turf was not acceptable
at initiation
Jay
Tifgrand Bermuda
Trts applied July 7
Fertilized 4 weeks prior
Soil pH 7.3
Turf was acceptable at
initiation
Rates
10# Fe / A
Fert w/ 3% Fe applied at
~300# / A
Most applicators use 200-
300# / A with 1-3% Fe
which supplies 2-6# Fe /
A
20# Fe / A
Fert w/ 6% Fe applied at
~300# / A
20# is generally the
highest recommended
Variables Analyzed
Rapid Laboratory Extraction
Turf Quality
– 1 to 9
Yield
– grams
NDVI
– Normalized difference vegetation index
– Measures natural green color
Rapid Extraction Setup
Rapid Lab Extraction
Extr 0 Extr 1 Extr 2 Extr 3 Extr 4
Fe E
xtra
cte
d (
%)
0
50
100
150
200
250
300
350
Sulfate
Sucrate
Humate
Oxide
Chelate
Cumulative Fe Extracted (%)
313 a
103 b
35 c
4 d 0.5 d 0
50
100
150
200
250
300
350
Chelate Sulfate Humate Sucrate Oxide
Aerial Photo – Citra week 3
Turf Quality
Jay - Tifgrand
Days after Fertilization
0 7 14 21 28 35
Turf
Qualit
y4
5
6
7
8
9
10
Control
Sulfate
Sucrate
Humate
Oxide
Chelate
Sulfate-F
Citra - Princess
Days after Fertilization
0 7 14 21 28 35
Tu
rf Q
ua
lity
4
5
6
7
8
9
10
Control
Sulfate
Sucrate
Humate
Oxide
Chelate
Sulfate-F
Initiated May 7, 2014 Initiated July 7, 2014
Turf Quality
a
b bc bc
bc bc c
4
5
6
7
8
9
Sulfate-F Chelate Sulfate Sucrate Oxide Humate Control
Jay - 16 DAA
Turf Quality
a
b b b bc bc
c
4
5
6
7
8
Sulfate-F Sucrate Humate Control Chelate Oxide Sulfate
Citra - 4 DAA
NDVI
Jay - Tifgrand
Days after Fertilization
0 7 14 21 28 35
ND
VI
0.52
0.54
0.56
0.58
0.60
0.62
0.64
0.66
Control
Sulfate
Sucrate
Humate
Oxide
Chelate
Sulfate-F
Citra - Princess
Days after Fertilization
0 7 14 21 28 35
ND
VI
0.52
0.54
0.56
0.58
0.60
0.62
0.64
0.66
Control
Sulfate
Sucrate
Humate
Oxide
Chelate
Sulfate-F
NDVI
a
ab ab b b
b b
0.56
0.57
0.58
0.59
0.6
0.61
0.62
Sulfate-F Chelate Humate Oxide Control Sulfate Sucrate
Jay - 21 DAA
NDVI
a a a
ab ab
ab
b
0.56
0.57
0.58
0.59
0.6
0.61
0.62
Sulfate-F Control Humate Chelate Sulfate Sucrate Oxide
Citra - avg
Yield
Citra - Princess
Days after Fertilization
7 14 21 28 35
Yie
ld (
g)
2
4
6
8
10
12
Control
Sulfate
Sucrate
Humate
Oxide
Chelate
Sulfate-F
Jay - Tifgrand
Days after Fertilization
7 14 21 28 35
Yie
ld (
g)
2
4
6
8
10
12
14
16
18
Control
Sulfate
Sucrate
Humate
Oxide
Chelate
Sulfate-F
Average Yield (g)
a a a a a a
a
0
10
20
30
40
50
60
Control Sucrate Humate Chelate Oxide Sulfate-F Sulfate
Jay
Citra
Average Yield (g)
a a a a a a
a
a a a a
a
a a
0
10
20
30
40
50
60
Control Sucrate Humate Chelate Oxide Sulfate-F Sulfate
Jay
Citra
Discussion
Why are granular Fe sources not
influencing turf response?
– Distribution Uniformity
– Oxidation
Oxidation presentation
Summary
Chelate and sulfate produced the highest
amounts of extractable Fe
Foliar sulfate increased turf quality on Princess
and Tifgrand
Tifgrand - foliar sulfate and chelate were the
only source that increase turf color
No source influenced yield
Summary cont.
Granular Fe sources may not provide a
visual response in terms of quality or color
at 10 or 20# Fe / A
Foliar applications should be considered
Contact Info
Travis Shaddox
University of Florida
Environmental Horticulture
office 352-273-4591
cell 352-262-3426
http://wfrec.ifas.ufl.edu/turfgrass/wp-content/uploads/sites/2/2014/10/FTGA-Iron.pdf