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SEAISLE1
MANAGEMENT section
GOLF MANAGEMENT - Fertility
Proper fertilisation
of any lawngrass is an important
component of the best management
practices of your home lawn. Fertilisation
and other cultural practices influence
the overall health of your lawn,
and can reduce or increase its
vulnerability to numerous stresses,
including weeds, insects, and
disease.
SeaIsle
Paspalum responds
well to low fertility rates. As
with any lawn, the fertility regime
will determine not only the rate
of growth and curb appeal of your
lawn, it will also determine the
amount of maintenance required
to keep it in optimal condition.
During establishment
of a Seashore
Paspalum lawn, small amounts
of fertiliser should be applied
on a regular basis to hasten growth
and ground cover. "Spoon-feeding"
0.5kg per 100 sq. metres (1/2
lb. of nitrogen per 1000 square
feet) in two applications during
a 3-4 week period will stimulate
growth.
To encourage root
development, phosphorous should
be applied during establishment
at rates equal to or greater than
the nitrogen. Potassium needs
of Seashore
Paspalum are also greater
during establishment, particularly
when irrigated with saline water.
Until the grass provides a uniform
ground cover, a 1:2:3 fertiliser
ratio of N:P:K in biweekly applications
will provide the needed nutrients.
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DETAILED INFORMATION
Paspalum
absorbs very little N during
the first month after planting.
The grass prioritises root
development. Medium to high
levels of P and K are essential
for rhizosphere development,
especially in salt-affected
environments. Basic fertilisers
with ratios of 1:2:3 (N:P:K)
or 1:3:4 are adequate during
this period. Rates of 2.5g
per 100 sq. metres (0.33-0.50
lbs./1000 sq. ft.) biweekly
for the first month are
adequate if P and K soil
levels are medium to high.
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Normal
grow-in from sprig planting
is 2-3 months, depending
on sprig volume and water
quality. An aggressive "bermuda-grass
fertility program"
will escalate the grow-in.
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About
4 weeks after planting
when stolons become visible
from the initial sprigs,
a complete fertiliser
(i.e., 2:1:3, 1:1:2, 1:2:2,
or 1:1:1 N-P-K) should
be applied at 0.5kg per
100 sq. metres (1 lb./1000
sq. ft.) Soil temperatures
should be >12.8C (55F)
and pH >5.5 for maximum
conversion of NH4+ to
NO3-.
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Repeat
fertiliser applications
every 2-3 weeks until
grow-in is 90% complete.
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Enhance
grow-in by verticutting
or slicing, beginning
at weeks 5 or 6. Apply
2.5-5.0 g per 1 sq. metre
(0.50 -1 lb./1000 sq.ft.)
of a highly soluble nitrate
source i.e., Ca (NO3)2
and irrigate. Repeat on
14-day cycles, verticutting
in different directions
each time.
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If
the site is sodded, fertilisation
is the same as for the
initial stolon establishment
and for the second treatment
at 4 weeks.
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If
salt-laden water is used
for irrigation, higher
than normal levels of
P and K plus micronutrients
may be needed due to high
leaching volumes. Using
highly soluble nitrate
sources can also be beneficial.
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The
Seashore
paspalums developed
nutrient uptake and utilisation
mechanisms which provide
functional growth and development
under very low nutrient
availability and severe
nutrient imbalance situations.
In general, SeaIsle
1 has lower nutrient
requirements and a higher
efficiency uptake system
than bermudagrass
or other warm
season grasses. Adjust
the ferility program to
account for nutrients supplied
by the irrigation water.
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Paspalum
will not take up NH4+
Nitrogen or urea Nitrogen
directly. These compounds
must be transformed to
NO3- Nitrogen prior to
paspalum
uptake (soil temperature
> 12.8C or 55F and
pH>5.5).
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If
the soil pH <5.5, a
lime addition can enhance
microbial conversion of
NH4+ Nitrogen or urea
Nitrogen to NO3- Nitrogen.
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Fertilisation
schedules for paspalum
are essentially a cool-season
grass regimen:
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Moderate amounts (0.25-0.49
kg N/100 sq. m or 0.50-1.0
lb./1000 sq.ft.)
in the Spring and Autumn
months.
- Minimal monthly amounts
(0.16-0.32 kg N/100
sq. m or 0.33-0.66 lb.
N/1000 sq.ft.) during
the high heat times of
summer.
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Optimum
annual N rates range from
1-2 kg actual N /100 sq.
metres (2-4 lb. N/1000
sq.ft.). Compared to hybrid
bermudagrasses,
this amounts to 50 - 60%
less N fertiliser annually
in many environments.
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Avoid
high N rates going into
winter months to minimise
succulence and predisposition
to cold temperature injury.
Early to mid-fall applications
can range from 0.25-0.38kg
per 100 sq. metres per
month (0.50 - 0.75 lb./1000
sq. ft.).
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If
paspalum
is overseeded with a cool
season grass in the
Fall, avoid high N applications
until the paspalum
is completely dormant,
otherwise the paspalum
may remain vigorous with
a high growth rate and
become more succulent.
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Balance
quick release N sources
(rapid uptake, enhanced
recovery from injury)
with slow release sources
in a spoon-feeding approach.
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Balanced
fertilisers (i.e., 10-10-10,
or 19-19-19, N-P-K) can
be used in 0.125 -0.5kg
per 100 sq. metres (0.25-1.0
lb./1000 sq. ft.) increments
monthly from March to
June and September to
November in the northern
hemisphere.
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Excess
chloride in irrigation
water can suppress the
uptake of N
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Sufficient
K must be supplied to
paspalum
on a regular schedule.
Avoid exceptionally low
levels in the soil. Potassium
is essential for wear
tolerance and stress tolerance,
especially salinity/salt
tolerance.
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In
salt-challenged environments,
excess Na can suppress
K uptake. High volume
leaching to enhance net
downward movement of salts
will deplete the soil
of K - it is one of the
most mobile nutrients.
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At
least 3 - 8% K should
be maintained on soil
CEC sites.
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On
salt-affected fine-textured
soils, 0.41 - 0.82 kg
K/100 sq, m (1-2 lbs.
K2O/1000 sq.ft.) may be
needed on a 2 - 4 week
schedule.
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Apply
K at 1.5 - 2.0 times the
N rate (i.e., N:K2O ratios
of 1:1.5 to 1:2.0 or N:K
ratios of 1:1.25 to 1:1.66).
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High
rates (0.41-0.82 kg K/100
sq. m or 1-2 lbs. K2O/100
sq. ft.) should be applied
during mid-Autumn to enhance
winter hardiness.
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K
levels should be maintained
at high levels all year,
especially when poor quality
effluent is used for irrigation.
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Moderate
to high levels of P should
be available during establishment
and grow-in. P enhances
root system development.
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On
salt-affected sites when
constant leaching is used
to flush excess salts
downward and away from
the root system:
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Increase annual rates
by 25 - 50% to adjust
for leaching losses.
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Light, frequent applications
(3 - 6 applications annually).
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Paspalum
responds to Fe amendments
and rates of * 0.5kg per
100 sq. metres (1 lb./1000
sq. ft./) per application
on a monthly basis should
be supplied during the
growing season.
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In
salt-challenged environments
with high leaching rates,
Mn, Ca, Mg, and Fe should
be closely monitored for
deficiencies.
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In
non-salt affected environments,
paspalum may need applications
of Na as a micronutrient
(rock salt, Na-based broad
spectrum micronutrient
sources) when using potable
water.
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Optimum
annual N rates of 0.98
- 1.96 kg/100 sq. m (2
- 4 lbs./1000 sq. ft.)
in regions with winter
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Optimum
annual N rates of 1.47
- 2.94 kg/100 sq. m (3
- 6 lbs./1000 sq. ft.)
in humid tropical regions
with year round growing
seasons
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To
prevent the roughs from
going off color due to minimal
N applications and low maintenance,
apply high soluble N sources
(i.e., calcium nitrate)
at 0.16 - 0.32 kg/100 sq.
m (0.33 - 0.66 lb. N/1000
sq. ft.) plus iron at 0.25
kg/100 sq. m (.55 lb./1000
sq. ft.) as needed to maintain
the dark green color. A
light Primo application
(0.09 ai/acre) could prove
beneficial in maintaining
the cosmetic appearance
with minimal shoot growth
during high heat periods.
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GOLF
