evaluation of organic fertilizers and biostimulants on sand

evaluation of organic fertilizers and biostimulants on sand

919
International Turfgrass Society
Research Journal Volume 11, 2009
EVALUATION OF ORGANIC FERTILIZERS AND BIOSTIMULANTS
ON SAND-BASED GOLF GREENS AND FOOTBALL PITCHES
UNDER SCANDINAVIAN CLIMATE CONDITIONS
Trygve S. Aamlid* and Hans Martin Hanslin
ABSTRACT
An absolute condition for high-quality golf courses and athletic fields is an adequate fertilizer
programme. Many organic fertilizers, some of them also containing biostimulants, are on the market.
Our objective was to evaluate some of these products under Scandinavian climate conditions. The
fertilizers / biostimulants Gro-Power®, Turf Food, Golf Algin, Bio Kombi, Maxicrop™ and Flex™
were compared with Arena® mineral fertilizer (control) on a USGA green in 2005 (grow-in year) and
2006; and the products Golf Algin, ProGreen, Activo and Flex™ were compared with Fullgjødsel®
mineral fertilizer (control) on a sand-based football pitch in the same years. Within each experiment,
all treatments received the same amount of nitrogen (N) rate per year (2.5/1.7 kg N (100 m2)-1 on the
golf green and 3.0/2.8 kg N (100 m2)-1 on the pitch in 2005/2006, respectively. Inputs of other
nutrients varied depending on product tested. In 2005, products were applied at two or four week
intervals according to their label, but in 2006, all products were applied at biweekly intervals. On
average for the two year experimental period, none of the organic fertilizers / biostimulants caused
significant improvements in turfgrass overall impression compared with the control mineral fertilizer
treatments. Turf Food and ProGreen enhanced turfgrass grow-in on the green and pitch, respectively,
but when used as maintenance fertilizer, Turf Food, Golf Algin, Bio Kombi and Flex produced turf of
significantly less quality than the the control. Disadvantages of the test products were most
conspicuous in spring when N release was restricted due to low soil temperatures and in autumn when
the products resulted in significantly more diseases than the mineral fertilizer control. The only
product that resulted in significantly better turfgrass colour and tended to give higher overall
impression than the control was the humic acid based Gro-Power® when combined with Arena® at
two week intervals; however, the inclusion of Gro-Power® products also increased fertilizer costs by
72% in the grow-in year and 124% in the subsequent year. In conclusion, light and frequent
applications of mineral fertilizer should always form the nutritional basis for sand-based greens and
football pitches in Scandinavia. Certain organic fertilizers and biostimulants may become useful
supplements for turfgrass grow-in and as maintenance fertilizers during the warmest summer period.
Keywords: humic acid, nitrogen, sea weed, turfgrass diseases, turfgrass quality
Trygve Aamlid*, The Norwegian Institute for Agricultural and Environmental Research,
Bioforsk Øst Landvik, Reddalsveien 215, NO-4886 Grimstad, Norway; H. M. Hanslin, The
Norwegian Inst. for Agr. and Env. Res., Bioforsk Vest Særheim, Postvegen 213, NO-4353
Klepp, Norway. *Corresponding author: ([email protected]).
920
INTRODUCTION
One of the most important conditions
for a healthy and wear-resistant turf cover is
an adequate fertilizer programme. To
improve drainage and facilitate all-weather
use, modern golf greens and football pitches
have sand-based root zones with very low
nutrient contents and poor buffering
capacity. While grasses growing on such
media require high and well-balanced
fertilizer inputs, the root zones are also
vulnerable to leaching, especially during turf
grow-in (Aamlid, 2005). Therefore, one of
the biggest challenges for greenkeepers and
groundsmen is to develop a balanced and
cost-effective fertilizer programme that
maintains a healthy, wear-tolerant and highquality turf cover.
A number of fertilizer products,
many of them especially designed for golf
greens and/or athletic fields, have been
introduced on the market. Most of the
products contain some of the nutrients in
organic form which is dependent on
microbial decomposition in order to become
available for plant uptake (Carrow et al.,
2001). Such organic fertilizers may well
enhance the microbial activity of the root
zone, but the release of N and other nutrients
depends on soil temperature, water
availability, pH, carbon/N ratio and a
number of other factors which makes it
difficult to maintain a balance between
nutrient availability and plant requirement
during the growing season. Some the
products also contain biostimulants, i.e. nonnutritive substances that enhance plant
growth by either chelation and thus
facilitated uptake of nutrients, direct supply
of plant hormones, or indirect stimulation of
plant hormonal activity (Elliott and Prevatte,
1996). Among the claimed advantages of
such biostimulants are better root
development, improved disease resistance,
improved stress tolerance, enhanced thatch
decomposition and a general improvement
in turf health and quality (Schmidt, 1998,
Zhang et al. 2003, Hunter and Butler, 2005;
Ervin and Chang, 2008). Most of the
combined organic fertilizer / biostimulant
products are two to ten times more
expensive per kilo nutrient, and turf
managers often wonder if they are worth the
extra costs compared to straight mineral
fertilizer. Thus, the objective of this research
was to provide unbiased information on the
potential advantages of such products under
Scandinavian climate conditions.
MATERIALS AND METHODS
Products tested
In spring 2005, companies selling
fertilizers and biostimulants on the
Scandinavian turfgrass market were
invited to have their products evaluated in
a two year project including the grow-in
year and subsequent year on an
experimental green and/or a sand-based
football pitch. As our intention was to
establish information on individual
products or ‘product families’ (examples
of ‘product families’ are Gro-Power®,
Flex™, Turf Food® etc.), combinations of
different organic fertilizers/biostimulants
were not allowed unless at least one of the
products was also tested individually. We
defined a control treatment consisting of
granular mineral fertilizer including
micronutrients; Arena® (grain size
< 2 mm) on the experimental green and
Fullgjødsel® (agricultural fertilizer) on the
experimental
football
pitch.
The
commercial partners decided if they
wanted their product tested either alone or
in combination with the fertilizer type
used in the control. In both experiments, it
was ensured that all treatments gave
exactly the same amount of total N over
the season, but the supply of other
921
nutrients varied with treatments. In 2005,
application intervals varied according to
the companies’ recommendations for their
products, but in 2006 all products were
applied at two week intervals as in the
control treatments. Fertilizer plans were
approved by the commercial partners
before each growing seasons. Seven and
five treatments were entered on the golf
green and football pitch, respectively.
Experimental sites
The experimental golf green was
located at Bioforsk Landvik in southeast
Norway (58°20’N, 8°31’ E, 12 m a.s.l.) and
the experimental football pitch at Bioforsk
Særheim in southwest Norway (58°46’N,
5°39’E, 80 m a.s.l.). Both research stations
have a temperate oceanic climate with cool
summers, but the winters are usually colder
and with more snow at Landvik than at
Særheim. During the winter 2005/06, the green
at Landvik was covered by snow from 18 Jan.
until 12 Apr., while the pitch at Særheim only
experienced occasional and temporary snow
cover. The 6ºC soil temperature threshold
characterizing the start of the growing season
was reached on 23 Apr. at Landvik, and 16
Apr. at Særheim, Further meteorological data
are provided in Table 1.
Golf green experiment
The experimental USGA-spec. green
at Landvik was constructed in November
2004. The root zone mineral matter
consisted of 0.2 % (w/w) fine gravel
(> 2.0 mm), 10.2 % very coarse sand (1.02.0 mm), 22.9 % coarse sand (0.5-1.0 mm),
37.6% medium sand (0.25-0.5 mm), 14.2 %
fine sand (0.15-0.25 mm), 4.6 % very fine
sand (0.06-0.15 mm), 0.3 % silt (0.0020.06 mm) and 0% clay (<0.002 mm).
Twelve per cent (v/v) of Sphagnum peat had
been incorporated into the sand before
construction, giving an initial organic matter
content (ignition loss) of 1.5%. The initial
pH (H2O) was 5.0, but this was raised to 6.3
by applying and raking in 30 kg of granular
lime (54 % CaO) per 100 m2 before sowing.
The
different
fertilizer
and
biostimulant types constituting the various
treatments are given in Table 2. Except for
the first application, corresponding to 0.8 kg
N (100 m2)-1, which was raked into the 3 cm
topsoil on 30 May 2005, solid fertilizers /
biostimulants were applied with an
experimental plot spreader, and liquid
fertilizers / biostimulants (Maxicrop™ and
Flex™) with an experimental backpack
sprayer. The liquid fertilizers were diluted
with water to an application volume of 5 L
(100 m2)-1. The green was irrigated with 3-8
mm after each application of solid products
and with another 2-5 mm within one hour
after each application of liquid products. In
all treatments the total amount of N was
2.5 kg (100 m2)-1 in the grow-in year 2005
and 1.7 kg N (100 m2)-1 in 2006.
Table 1. Mean monthly air temperature and monthly rainfall during the growing seasons 2005 and 2006 as
compared to 1961-1990 normal values for Bioforsk Landvik (golf green) and Bioforsk Særheim (football pitch).
Apr.
May
Jun.
Jul.
Aug.
Sep.
Oct.
Sum/Mean
Bioforsk Landvik: Golf Green
Air temperature, °C
Rainfall, mm
2005
2006 Norm
2005
2006 Norm
6.1
4.4
5.1
38
86
58
9.8
11.1
10.4
129
98
82
14.3
15.0
14.7
55
32
71
17.8
19.2
16.2
92
51
92
15.6
17.2
15.4
100
134
113
12.9
15.0
11.8
49
135
136
9.1
10.2
7.9
152
221
162
12.2
13.2
11.6
615
757
714
Bioforsk Særheim: Football Pitch
Air temperature, °C
Rainfall, mm
2005
2006 Norm
2005
2006 Norm
7.1
4.7
5.1
85
134
55
8.4
10.1
9.5
87
45
58
11.6
12.1
12.5
33
53
70
14.8
16.9
13.9
47
58
94
13.6
16.2
14.1
126
157
110
12.6
15.8
11.5
186
107
156
10.6
11.1
8.6
116
207
152
11.2
12.4
10.7
680
761
695
922
Table 2. Fertilizer products, inputs of P and K, and fertilizer costs (updated 1 March 2009) in field trial on a USGA green at
Bioforsk Landvik in 2005 (grow-in year) and 2006. The total amounts of N in all treatments were (2.5 kg 100 m2)-1 in 2005
and 1.7 kg (1.71 kg 100 m2)-1 in 2006. Information about fertilizer products was provided by manufacturer or representative.
Treatment &
‘Product
familiy’
®
1. Arena
+
Fullgjødsel®
(control)
Mfg.
Yara
International,
Norway
General
description1
®
Actual
product(s)
used
Nitrogen
form1
Gyllebo
Gödning,
Sweden
2005
P
K
2006
P
K
Costs
kg/100 m2 kg/100 m2
2005 2006
†NOK per
100 m2
0.60
®
Arena Høst 72% NH4,
Arena :
Mineral
Extra 3-3-15 28% urea
ferttilzer,
Arena® Start 47% NO3,
granules
22-3-10
53% NH4
<2 mm
Arena® Green 26% NO3,
+
Plus 12-1-14 74% NH4
Fullgjødsel®:
Arena® Score 18% NO3,
Granular
12-1-14
54% NH4,
mineral
28% urea
fertilizer
®
Arena
Golf
23%
NO3,
developed for
agricultural Extra 13-0-15 48% NH4,
29% urea
crops.
Fullgjødsel® 47% NO3,
18-3-15
53% NH4
2. GroGro-Power®, Humus-based Gro-Power® 20% NH4,
Power®
USA
fertilizers /
Premium
80% urea
soil
Green 5-3-1
conditioners
Gro-Power®
0-0-15 + Ca
Gro-Power®
45% Mg
Gro-Power®
35% Mn
3. Turf Food Novozymes Feathermeal +
Turf Food
25% NH4,
14-3-5*
Biologicals,
sea weeds +
43% urea,
humic subst.
France
32% water
+
insoluble
methylen-urea
Turf Food
5% NH4,
+ mineral N
15-3-8*
12% urea,
70% water
insoluble
Turf Food
12% NH4,
5-2-12*
13% urea,
75% water
insoluble
4. Golf Algin
Tilcho
Sea weeds, Golf Algin S 12% NO3,
Biochemie,
71% NH4
Laminaria
Germany
and
Algin Food S 51% NO3
Ascophyllum , Golf Algin A 10% NO3,
granules
75% NH4
< 2 mm
5. Bio
Kombi
Application
interval /
combinations
Poultry
Bio Kombi Kmanure, min. Spec. 5-1-17
fertilizer,
+ Fe
meat/bone
Bio Kombi
meal,
Green Start
biproducts
12-2-6 + Fe
from yeast
Bio Kombi
production. Green Season
10-2-10 + Fe
Alternating
products
every two
weeks
3.6
0.20
1.6
364
178
3.3
0.22
2.3
626
399
Alternating
products
every four
weeks in 2005 0.26
and every two
weeks in
2006.
2.6
0.14
1.0
462
299
Alternating
products
every four
weeks in 2005 0.26
and every two
weeks in
2006.
2.6
0.18
1.1
770
549
17% NO3,
17% NH4, Alternating
66% org.N
products
every four
10% NO3,
10% NH4, weeks in 2005 0.46
66% org.N and every two
weeks in
Mostly
2006.
organic (not
specified)
3.0
0.33
1.7
204
137
Before
sowing only
Alternating
products in
combination
with Arena®
and
0.45
Full-gjødsel®
(as in control
treatment)
every 2 weeks
923
Table 2, continued.
Treatment
& ‘Product
family’
Mfg.
General
description1
Actual
product(s)
used
Nitrogen
form1
Application
interval /
combinations
2005
P
K
2006
P
K
kg/100 m2 kg/100 m2
6. Maxicrop™
7. Flex
Maxicrop
Concentrated
International,
sea weed
extract
Norway
Flex Agri,
Norway
Liquid
fertilizer,
mostly
organic
Maxicrop™
no 1 Triple
Seaweed
3-0.5-3
Maxicrop™
no 3 Pro-K
Plus 2-0-15
-
NK 10-0-8
Golfgødning
10% NO3,
11% NH4,
79% amides
17% NO3,
17% NH4,
66% amides
100%
amides
NPK 12-2-4
Micro
NPK 2-2-6
† 100 NOK = 12 Euros = 15 USD
The green was seeded with a creeping
bentgrass blend composed of ‘Penn A-1’, ‘Penn
A-4’, and ‘Penn G-6’ (Agrostis stolonifera, 1/3
of each cultivar) on 7 June 2005. Mowing was
accomplished with walk-behind green mowers
three times per week. Except during grow-in and
in early spring and late autumn, mowing height
was 4.5 mm in 2005 and 3.0 mm in 2006.
Vertical cutting and dressing with straight sand
(no organic matter) was accomplished three
times in 2005 and six times in 2006. The green
was not in regular play, but plots received
abrasive wear and compaction from a drum with
golf spikes two to three times a week. No
pesticides or growth regulators were used. The
experiment followed a randomized complete
block design with three blocks (replicates) and a
plots size of 4.5 x 1.5 = 6.75 m2.
Football pitch experiment
The experimental football pitch at
Særheim was constructed in autumn 2004 with
a 30 cm layer of straight sand practically
without organic matter ( ignition loss 0.2 %, pH
(H2O) 6.9) on top of a self-draining moraine.
The experiment had four blocks (replicates)
and a plot size of 1.5 m x 4 m = 6.0 m2.
In
combination
with Arena®
and
Fullgjødsel® 0.47
four times in
2005 and
every two
weeks in 2006
-
Alternating
products
every
two weeks
0.35
Costs
2005 2006
NOK per
100 m2
3.1
0.18
1.5
331
274
2.1
0.14
1.2
135
95
The
different
fertilizer
and
biostimulant types constituting the various
treatments are given in Table 3. Solid
fertilizers (Fullgjødsel®, Golf Algin and
ProGreen) were spread by hand in cross and
liquid fertilizers (Activo and Flex™) by a
can after dilution to an application volume
of 1.17 L m-2. The first applications
corresponding to 0.5 kg N (100 m2)-1 in all
treatments were raked into the 5 cm topsoil
before sowing a mixture of Poa pratensis
’Limousine’ (70%) and Lolium perenne
‘Baraine’ (30%) on 3 June 2005. All
treatments received 3.0 kg N (100 m2)-1 in
2005 and 2.8 kg N (100 m2)-1 in 2006. The
pitch was irrigated with 7 mm after
application of solid fertilizer and with
another 3 mm after application of liquid
fertilizer.
Otherwise,
irrigation
was
accomplished as needed. The pitch was
mowed with a rotary mower to 3.5 cm
whenever it had reached 5.0 cm (one to two
times per week depending on season).
Clippings were always removed. Moderate
wear was imposed by dragging a drum with
16 mm football knots across the pitch at
regular intervals.
924
Table 3. Fertilizer products, inputs of P and K, and fertilizer costs (updated 1 March 2009) in field trial on a sandbased football pitch at Bioforsk Særheim in 2005 (grow-in year) and 2006. The total amounts of N in all treatments
were (3.0 kg 100 m2)-1 in 2005 and 2.8 kg (3.0 kg 100 m2)-1 in 2006. Information about fertilizer products was
provided by manufacturer or representative.
Treatment &
‘Product
family’
Mfg.
General
description1
Actual
product(s)
used
Nitrogen
form1
Application
interval /
combinations
2005
P
K
2006
P
K
kg/100 m2 kg/100 m2
®
1.Fullgjødsel
(control)
2. Golf Algin
3. ProGreen
4. Activo
5. Flex
Yara
Granular min.
International, fertilizer for
Norway
agric. crops.
Tilco
Biochemie,
Germany
Osmo
Organic
Fertilizers,
Belgium
Osmo
Organic
Fertilizers,
Belgium
Flex Agri,
Norway
®
Fullgjødsel
18-3-15
Fullgjødsel®
11-5-18
micro
Fullgjødsel®
6-5-20 micro
Golf Algin S
47% NO3,
53% NH4
41% NO3,
59% NH4
Every two
weeks
Costs
2005 2006
†NOK per
100 m2
0.65 3.10 0.49 2.48 105
23% NO3,
67% NH4
12% NO3,
Alternating
Sea weeds
products
71% NH4
Laminaria
every four
and
Algin Food S 51% NO3
Ascophyllum, Golf Algin A 10% NO3, weeks in 2005 0.30 3.45
granules
75% NH4 and every two
< 2 mm
weeks in
2006.
Granulated
50% urea,
ProGreen
organic and
Park &
50% organic
organic /
Fairway
N
mineral
12-2-4
Alternating
fertilizers
products
ProGreen
100%
0.50 2.94
from animal
every two
Universal
organic
and plant
weeks.
7-1-7
sources,
ProGreen
100%
Bacillus and
Autumn
organic
seaweed.
5-1-10
Bloodmeal + Activo 3-3-6
100%
In
organic
combination
humic subst.
+ beetpulp
with Progreen
(liquid form)
three times in
0.58 3.08
2005 and
every two
weeks in
2006.
Liquid
NK 10-0-8
10% NO3,
Alternating
fertilizer,
Golfgødning 11% NH4,
products
mostly
79% amides
every
two
organic
NPK 12-2-4 17% NO3,
weeks.
Micro
17% NH4,
Fullgjødsel® 0.69 3.74
66% amides
given
NPK 2-2-6
100%
pre-sowing as
amides
in control
85
0.27 1.66 843
901
0.46 2.22 399
337
0.50 2.27 399
334
0.25 1.92 221
172
treatment.
† 100 NOK = 12 Euros = 15 USD.
Assessments and statistical analyses
In both experiments, turfgrass
colour, tiller density, per cent of plot
affected by disease and turfgrass overall
impression (visual merit) were assessed at
two to four weeks intervals throughout both
growing seasons. Turfgrass colour, tiller
density and overall impression were
estimated on scale from 1 to 9 where 9 was
the darkest colour, highest visual density
and
best-looking
turf,
respectively.
Additional observations in the grow-in year
925
included per cent coverage two to three
weeks after sowing in both experiments and
soil mineral N analysed as described by
Riley et al. (1993) one week after sowing in
the green experiment. Cylinder samples for
determination of thatch thickness and shoot
dry weight and root dry weight in various
layers were taken in 2006, and samples for
analyses of soil phosphorus
(P) and
potassium (K) at the start of experimentation
in May 2005 and end of experimentation in
October 2006.
The
experimental
data
were
subjected to conventional analyses of
variance (PROC ANOVA, Statistical
Analyses System). Before these analyses,
visual merit-, tiller density-, and colour
scores were averaged over the spring (until
10 June, 2006 only), summer (10 June–10
Sep.), and autumn (10 Sep.–10 Nov.)
periods. The significance levels P<0.001,
P<0.01, P<0.05, P<0.10 and ns have been
indicated by ***, **, *, (*), and ns,
respectively. LSD-values have been
indicated for effects significant at P<0.05.
RESULTS
Golf Green Experiment
Soil mineral N, turfgrass establishment and
coverage. Two weeks after sowing, plots
receiving Turf Food had significantly better
plant coverage than plots receiving other
fertilizer types (Table 4). Next to plots
receiving Gro-Power® plus Arena®, plots
receiving Turf Food also had the highest
content of soil mineral N in the grow-in
phase. The slowest establishment was found
on plots receiving Golf Algin. On average
for the two year experimental period, the
most complete turfgrass coverage was found
on plots receiving Arena®, either alone
(control treatment) or in combination with
Gro-Power®. Plots receiving Bio Kombi
had significantly less coverage than plots
receiving other types of fertilizers.
Diseases, moss, winter injury, and spring
green-up. Patches of diseases started to
appear in October 2005. Samples
diagnosed at the Bioforsk Plant Health
Clinic showed that these patches were due
to Microdochium nivale and Pythium spp.
In August and September 2006, an
outbreak of Leptospherulina leaf blight
(causal fungus Leptospherulina australis)
was diagnosed. Plots receiving GroPower®, Turf Food, Golf Algin, Bio
Kombi and Flex™ had significantly more
of these diseases than control plots
receiving only mineral fertilizer (Table 4).
In autumn 2006, there was more moss on
plots fertilized with Turf Food or Bio
Kombi than on plots fertilized with other
fertilizer types.
In April 2006, after almost three
months of snow cover, there tended
(P=0.08) to be less winter injury on control
plots than on plots receiving Gro Power® in
addition to Arena®. Most of this winter
injury was due to Microdochium nivale. As
the disease was mostly limited to the leaves,
the turf recovered within a month after snow
melt. Green-up was one to two days later on
plots receiving Bio Kombi or Maxicrop than
in the other treatments (data not shown).
Turfgrass colour, tiller density and
overall impression. On average for two
experimental years, turfgrass colour was
significantly better on plots fertilized with
Gro-Power® than on control plots (Table
4). Application of the other fertilizer /
biostimulant types resulted in lighter
colour than on the control plots. Regular
use of Turf Food, Golf Algin, Bio Kombi
or Flex™ resulted in significantly lower
tiller density than in the control treatment.
926
Table 4. Effect of fertilizers / biostimulants on soil and turfgrass characteristics on a USGA green at Bioforsk
Landvik, southeast Norway during 2005 (grow-in year) and 2006.
Treatment &
Fertilizer /
biostimulant
products
1. Arena® (control)
2. Gro-Power®
+ Arena®
3. Turf Food
4. Golf Algin
5. Bio Kombi
6. Maxicrop™
+ Arena®
7. Flex™
Sign.
LSD0.05
Treatment &
Fertilizer /
biostimulant
products
1. Arena® (control)
2. Gro-Power®
+ Arena®
3. Turf Food
4. Golf Algin
5. Bio Kombi
6. Maxicrop™
+ Arena®
7. Flex™
Sign.
LSD0.05
1
Soil min-N,
one week
after sowing
(kg N ha-1)
Turf cover, %
% of plot area
19
2 wk after
sowing
18
2 year
mean
96
Diseases,
2 yr mean
2
Moss,
Oct. 2006
0
Winter
injury,
April 2006
82
41
20
97
5
0
92
34
24
28
30
15
21
93
94
90
4
6
7
1
0
1
88
88
86
15
20
94
3
0
88
18
**
16
Turfgrass
colour,
2 yr mean
(1-9)1
5.7
20
***
6
Tiller
density,
2 yr mean
(1-9)1
6.9
94
***
2
4
*
2
2 yr
mean
6.2
2005
mean
6.6
Spring
2006
5.0
Summer
2006
6.0
Autumn
2006
6.0
6.1
7.2
6.5
6.8
4.8
6.6
6.5
5.1
5.2
4.7
5.3
6.2
4.9
5.0
5.4
4.5
4.9
5.4
4.5
4.2
4.3
3.6
5.7
6.2
5.1
4.8
4.5
4.3
5.1
6.3
5.8
6.2
3.9
6.0
5.7
5.2
***
0.2
5.9
***
0.8
5.6
***
0.5
5.6
***
0.5
4.4
**
0.7
6.6
***
0.5
4.5
***
1.1
0
84
***
(*)
1
Overall impression (1-9)1
9 designates darkest green colour, highest visual density and highest overall visual rating.
Both when considering each year
separately and on average for the two year
experimental period, turfgrass overall
impression was significantly better on
control plots and plots fertilized with GroPower® than on plots fertilized with Turf
Food, Golf Algin, Bio Kombi or Flex™
(Table 4). Division of the 2006 mean value
into spring, summer and autumn values
showed that than advantages of the mineral
fertilizer control was most apparent in
spring and autumn. During summer, many
of the organic fertilizer products /
biostimulants gave turfgrass qualities equal
to or even better than the control treatment.
The lower ratings for most test plots than
for control plots in autumn were usually
due to more diseases.
Thatch accumulation, root development and
soil parameters. Cylinder samples taken in
October 2006 indicated an average thatch layer
of 12 mm; thatch thickness was not influenced
by fertilizer treatments. Various fertilizer
treatments also had no effect on the total shoot
or root weight by the end of the experiment
(data not shown).
Soil chemical analyses taken at the end
of the experiment in October 2006 showed no
significant difference in ammonium-lactateextractable soil phosphorus (P-AL) compared
with values 16 months earlier. The average
value was still 1.1, with a variation from 0.8 to
1.5 mg P (100 g dry soil)-1. By contrast, the
average content of potassium (K) had almost
tripled from 1.6 to 4.6 (range 3.26.0) mg K
(100 g dry soil)-1.
927
Table 5. Effect of fertilizers / biostimulant products on soil and turfgrass characteristics on a football-pitch at
Bioforsk Særheim, SW Norway during 2005 (grow-in year) and 2006.
Treatment
no. &
Fertilizer /
biostimulant
products
1. Fullgjødsel
®
(control)
2. Golf Algin
3. ProGreen
4. Activo +
ProGreen
5. Flex™
Sign.
LSD0.05
1
Turf cover, %
3 wk
after 2 year
sowing mean
Overall impression (1-9) 1
Diseases,
% of plot
area,
2 year
mean
Turfgrass
colour,
2 year
mean
(1-9)1
Tiller
density,
2 year
mean
(1-9) 1
2 year
mean
2005
mean
Spring
2006
Summer Autumn
2006
2006
49
49
53
94
94
92
3
2
3
7.3
7.2
7.2
7.1
7.0
6.8
6.9
7.0
6.7
7.0
6.8
6.8
6.8
6.5
6.4
6.7
7.3
6.3
7.5
7.8
7.9
53
41
***
4
93
91
ns
4
4
ns
7.4
7.4
ns
6.9
6.9
ns
7.0
7.0
ns
7.3
6.8
ns
6.5
7.3
(*)
6.3
7.1
ns
7.8
7.8
ns
9 designates darkest green colour, highest visual density and highest overall visual rating.
Football pitch experiment
Three weeks after sowing, plots
receiving ProGreen or ProGreen + Activo
had slightly but significantly better turf
coverage than control plots, while Flex gave
considerably less cover (Table 5). However,
on average for the whole experimental
period, differences in turf coverage, colour,
tiller density or overall impression were not
significant.
The experimental football pitch did
not suffer any kind of winter damage, but in
some of the plots, perennial ryegrass was
affected by Fusarium in May 2006. There
was also a certain incidence of red thread
(Laetisaria fuciformis) later in the season,
but neither disease showed preference for
any of the fertilizer treatments.
As for the green experiment, various
fertilizer treatments had no effect on the
total shoot or root biomass at the end of the
experiment (not shown). At the end of the
first growing season, however, there were
contrasting allocation patterns with a
transition from a high shoot:root ratio (0.89)
for the control treatment to a low shoot:root
ratio for the Flex treatment (0.33). Thatch
thickness by the end of the experiment was
not affected by the treatments and ranged
between 8 and 12 mm.
DISCUSSION
Fertilizers for turfgrass grow-in
Turfgrasses growing in Scandinavia
are generally exposed to lower temperatures
than further south in Europe and in the USA
(Table 1). Low soil temperatures limit
microbial activity and thus nutrient release
from organic fertilizers (Carrow et al.,
2001). On the experimental green at
Landvik, this was probably a major reason
why control plots receiving mineral fertilizer
only gave the best overall impression in
spring 2006 (Table 4). However, as both the
experimental green and the experimental
football pitch were not seeded until early
June 2005 when soil temperatures had
reached an acceptable level, there is no
indication that soil temperature was limiting
to nutrient release from the organic
fertilizers in the grow-in phase. On the
contrary, soil samples taken about two
weeks after the initial fertilizer application at
Landvik indicated that the N availability
during establishment was considerably
higher on plots fertilized with Gro-Power®
or Turf Food than in the control treatment
(Table 4). As for Turf Food, the higher N
availability was also reflected in a better
plant cover about two weeks after sowing
(Table 4), and a similar benefit of ProGreen
was recorded in the pitch experiment at
928
Særheim. The enhanced establishment after
application of Turf Food or ProGreen shows
that a start application of an organic N
source may be advantageous on sand-based
greens and football pitches. This is
especially true as such growing media have
to be irrigated frequently rendering them
liable to leaching during establishment.
During the three weeks after sowing, the
sand-based green at Landvik received about
80 mm of natural rainfall plus at least
100 mm as bi-hourly irrigation on sunny
days. Use of organic fertilizers during
turfgrass grow-in will also enhance soil
microbial activity, particularly on greens and
pitches constructed
without
organic
amendment to the sand-based root zone
(Carrow et al., 2001). However, the large
span in shoot: root ratios at the end of the
first growing season indicated that nutrient
availability had been limiting for plant shoot
growth during establishment in the Flex
treatment on the football pitch.
In order to maximise N-use efficiency
and decrease leaching during turfgrass grow-in,
the organic fertilizer that is incorporated into the
soil before sowing ought to exhibit an
intermediate release pattern. As for the manurebased products included in these trials, our data
suggest that N was released faster from Turf
Food and ProGreen which contain feather-meal
and blood meal, than from Bio Kombi, which is
based on poultry manure and bone- and meat
meal. However, none of these products had a
sufficiently stable release of N to be
recommended as the only fertilizer source on
established golf greens or football pitches.
Biostimulant effects vs. nutrient effects
While most of the organic
fertilizers/biostimulants were applied at
monthly intervals according to their label in
2005, all products were applied at biweekly
intervals in 2006. While such a frequent
application regime should not be necessary
given the slow-release properties of many of
the products, this change in experimental
protocol was expected to maximise potential
biostimulant effects, i.e. effects beyond those
explained by the products’ content of N or
other nutrients. As biostimulants are hormonal
in nature (Ervin and Zhang, 2008) it was
expected that frequent low-dose applications
would be more beneficial than infrequent,
high-dose applications. However, despite this
change in protocol, the ranking of various
treatments for turfgrass colour, tiller density or
overall impression was mostly the same in
2006 as in 2005 (Tables 4 and 5). With the
exception of Gro-Power®, it therefore seems
justified to attribute the performance of the
various products to their supply of major
nutrients, especially N, rather than to their
content of biostimulants. This does not imply
that biostimulants will never play a role on
sand-based golf greens or football fields, but
under the present experimental conditions, the
biostimulant effects were mostly too subtle to
be of practical relevance.
Nitrogen vs. other macronutrients
Based on findings that the proportion
of various macronutrients in plant tissues is
virtually the same regardless of fertilization
regimes, Ericsson et al. (2006) recommended
that turfgrass fertilizers should have
N:P:K:Ca:Mg:S ratios of 100:14:65:7:6:9. In
the present green experiment, the N:P ratio in
the grow-in year varied from 100:8 in
treatment 3 (Turf Food) to 100:24 in the
control treatment (Inputs of P and K are
provided in Tables 2 and 3). Treatment 3
(Turf Food) was somewhat low also for K
(N:K = 100:56), but otherwise all treatments in
both experiments received adequate or
superfluous amounts of this element. While
many treatments had very low N:S ratios
(100:92 in the control treatment at Landvik;
data not shown) some of the product families
(Golf Algin, Flex™ and Bio Kombi) did not
supply calcium at all, and Bio Kombi was low
929
also for magnesium (N:Mg = 100:3 at Landvik
in both years). Although it cannot be ruled out
that deficiencies occurred during certain
periods in certain treatments, the fact that PAL values remained stable and K-AL values
increased from 2004 to 2006 suggests that
turfgrass growth or quality was rarely confined
by these elements. It is also possible that the
content of biostimulants in some of the
fertilizer products enhanced plant uptake of P
(Butler et al., 2008). As Carrow et al. (2001)
recommended pre-plant applications of 0.4 kg
P 100 m2)-1 on sandy soils low in P, one would
perhaps suspect green plots receiving Turf
Food to be low in this element during grow-in,
but this is hard to reconcile with the fact that
Turf Food resulted in faster grow-in than any
other treatment on the experimental green. All
in all, it seems fair to conclude that N
availability was the most important component
governing the outcome of this study.
Organic fertilizers / biostimulants
as supplements to mineral fertilizers
At the start of this project,
commercial partners were invited to decide
whether they wanted their product / product
family tested alone or in combination with
the mineral fertilizers used in the control
treatments. Apart form the pure sea weed
product Maxi Crop™, the only organic
fertilizer claimed to be tested in combination
with mineral fertilizer was GroPower®. In
the green experiment, this was also the only
treatment that significantly improved
turfgrass colour and tended to give higher
tiller density and overall impression than the
control (Table 4). Unlike most of the other
products, GroPower® does not contain slowrelease N, but has 80 and 20% of its N in the
form of urea and ammonium, respectively
(Table 2). Apart from the frequent
application pattern, this may be one of the
reasons why it produced so good results on
the experimental golf green. It can also not
be ruled out that the high content of humic
substances in GroPower® contributed to its
effect. Humic substances are a group of
biostimulants claimed to increase the soil’s
cation exchange capacity and water-holding
capacity, enhance bacterial propagation,
provide the turf with plant hormones such as
auxin and cytokinins, facilitate nutrient
uptake through chelation, and confer stress
tolerance through antioxidant production
(Liu et al., 1998; Zhang and Schmidt, 2000;
Hunter and Butler, 2005; Butler et al.,
2008), but it is not known which of these
effects, if any, were most important in the
present project.
The product families Turf Food, Bio
Kombi, ProGreen, and Activo are primarily
based on animal by-products. With the
exception of Bio Kombi, where N
availability seems limited, these products
may well enhance turfgrass establishment,
but they appear to give little comparative
advantage when applied to established turf.
As they also contain humic substances
and/or sea weed extracts, the specific
properties of these biostimulants would
perhaps have been more expressed had the
products been used in combination with
mineral N, as was the case for GroPower®
on the experimental green.
The two products primarily based on
sea weeds, Golf Algin and Maxicrop™, also
showed no advantage compared to the mineral
fertilizer control. Other workers have shown
sea weeds to enhance nutrient uptake and
increase stress tolerance, but the method of sea
weed processing seems fundamental to the
efficiency of the products (Hunter and Butler,
2005). Although use of sea weed composts for
agriculture and horticulture have a long
tradition along the Scandinavian coast, their
advantages may perhaps be more expressed
when plants are exposed to dryer conditions or
higher temperatures than in these experiments
(Schmidt, 1998).
930
Especially in the football pitch
experiment, turfgrass establishment in 2005
was considerably slower after use of the
liquid organic fertilizer Flex™ than in the
control treatment. Flex™ was therefore not
a good choice for the grow-in situation. In
the green experiment the visual rating of
Flex™ plots also dropped significantly
during the wet period in autumn (Table 4),
perhaps suggesting that the amides in Flex™
leached out of the soil even before being
mineralized. On the other hand, during the
hot period in summer 2006, Flex™ plots had
quality ratings equal to or better than control
plots at Landvik, and at Særheim they were
on the same level or slightly better than
control plots both in autumn 2005 and
throughout the growing season 2006. As the
risk for scorching or unwanted colour effects
are low with the use of Flex™, it seems to
be a good maintenance fertilizer, especially
during hot and dry periods in summer.
In total for the two year experimental
period, fertilizer costs for the various
treatments showed a six-fold variation on
the experimental green and a nine-fold
variation on the experimental football pitch
(Table 2). Except for Bio Kombi and
Flex™ on the experimental green, all
products were more expensive per unit N
than the mineral fertilizer used in the control
treatments. As practised in 2005, this may –
to some extent – be compensated by lower
labour cost resulting from longer application
intervals. However, given the quality ratings
in these trials, this does not justify the
recommendation of any of the test products
except for TurfFood or ProGreen /Activo
during turfgrass grow-in, Flex™ for
maintenance fertilization especially during
the summer months, and GroPower® as a
supplement to mineral fertilizer both for
establishment and maintenance.
CONCLUSION
This project has shown that the
fertilizer programme is of outmost
importance for the quality of sand-based
golf greens and football fields. Under
Scandinavian conditions with limited soil
temperatures, frequent applications of
mineral fertilizer has to be the cornerstone in
such a programme. Organic fertilizers with
biostimulants may supplement the mineral
fertilizer in the turfgrass grow-in situation
and as maintenance fertilizer during the
warmest and most stressful summer period.
ACKNOWLEDGEMENT
Besides the testing fees paid by
commercial partners, this research was
funded by the Norwegain Golf Federation,
The Football Association of Norway and
the Norwegian Ministry of Culture and
Church Affairs. Thanks are extended to
Anne A. Steensohn, Åge A. Brømnes, Åge
Susort and Palle Haaland for excellent
technical assistance.
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