Transcript of Evaluation of nitrogen fertilization and irrigation on St. Augustinegrass: NO 3 -N leaching and...
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- Evaluation of nitrogen fertilization and irrigation on St.
Augustinegrass: NO 3 -N leaching and turfgrass quality D. M.
Park
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- Use of St. Augustinegrass ~52,000 acres harvested in
2000~52,000 acres harvested in 2000 43,775 acres for new
residential starts43,775 acres for new residential starts
Right-of-ways,Right-of-ways, re-sodding, recreation, re-sodding,
recreation, commercial commercial From Haydu et al., 2002 Types of
grass in Florida shown as a percent of total production for
2000
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- Palm Beach Post May 17, 1998 Sun-Sentinel Sep 26, 1999 The
Orlando Sentinel May 9, 1998
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- Rationale South West Florida Water Management District
concerned over pollutionSouth West Florida Water Management
District concerned over pollution Decline in water qualityDecline
in water quality Overuse of water resourcesOveruse of water
resources
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- Literature review: N sources No N leaching differences from
different sources (Geron et al., 1993)No N leaching differences
from different sources (Geron et al., 1993) Cultural practices:
(ex. irrigation and mowing) (Snyder et al., 1976, 1980) (Cisar et
al., 1991) Cultural practices: (ex. irrigation and mowing) (Snyder
et al., 1976, 1980) (Cisar et al., 1991) Comparison of coated AN
versus non-coated AN in Myakka sand (Alva, 1992) Comparison of
coated AN versus non-coated AN in Myakka sand (Alva, 1992) N
requirement by different grass species (Sartain, 1992) N
requirement by different grass species (Sartain, 1992)
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- Literature review: N rates Increase N rate, increase N leaching
( Brown et al., 1977)Increase N rate, increase N leaching ( Brown
et al., 1977) (Cisar et al., 1991)
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- Literature review: Irrigation Scheduled irrigation reduced [N]
and leaching (Morton et al., 1988) Scheduled irrigation reduced [N]
and leaching (Morton et al., 1988) Increased N leaching from sand
soils from initial simulated rainfall events (Wang and Alva, 1996)
Increased N leaching from sand soils from initial simulated
rainfall events (Wang and Alva, 1996)
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- Literature review: St. Augustinegrass Focus on cool season
grasses and bermudagrass Focus on cool season grasses and
bermudagrass Minor information on St. Augustinegrass Minor
information on St. Augustinegrass Greater root density (Bowman et
al., 2002) Greater root density (Bowman et al., 2002) Only field
scale study in South Florida (Erickson et al., 2001) Only field
scale study in South Florida (Erickson et al., 2001) 0.4% N loss of
applied (Erickson et al., 2001) 0.4% N loss of applied (Erickson et
al., 2001)
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- The effect of N rate on NO 3 -N leaching, St. Augustinegrass
quality and clipping growth.The effect of N rate on NO 3 -N
leaching, St. Augustinegrass quality and clipping growth. The
effect of N sources on NO 3 -N leaching, St. Augustinegrass quality
and clipping growth.The effect of N sources on NO 3 -N leaching,
St. Augustinegrass quality and clipping growth. The effect of
irrigation rate and frequency on NO 3 -N leaching, St.
Augustinegrass quality and clipping growth.The effect of irrigation
rate and frequency on NO 3 -N leaching, St. Augustinegrass quality
and clipping growth. Objectives
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- Hypotheses N leaching will be minimized while maintaining
satisfactory turf quality: H 1 = Combining of soluble and
controlled release N products H 2 = Applying an optimum N rate H 3
= Applying optimum irrigation
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- Margate fine sand soil Margate fine sand soil siliceous,
hyperthermic Mollic Psamnaquent siliceous, hyperthermic Mollic
Psamnaquent
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- Split Plot Repeated Measure Irrigation treatments(main plot)
Irrigation treatments(main plot)X N sources N sources X (subplots)
N rates N ratesX 4 Reps 4 Reps Experimental design:
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- Install sample collection equipment Ceramic- cup sampler 40
cm
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- Location of ceramic-cup samplers, tubing, and sprinklers Cup
samplers Vacuum & sample lines Sprinkler heads
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- Grass selection Stenotaphrum secundatum (walt.) kuntze cv.
Floratam Stenotaphrum secundatum (walt.) kuntze cv. Floratam From
Haydu et al., 2002 Top four St. Augustinegrass types grown in
Florida in 2000 Floratam 79% Palmetto 7% Floralawn 6% Bitterblue 3%
Other 6%
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- Two experiments YEAR 1 (EXP.I) 2 irrigation schedules2
irrigation schedules 4 N sources4 N sources 3 N rates3 N rates YEAR
2 (EXP.II) 2 irrigation schedules2 irrigation schedules 6 N
sources6 N sources 2 N rates2 N rates Six, 2 month fertilization
cycles Six, 2 month fertilization cycles
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- EXP. I: M&M Irrigation treatments (2) Excessive: 125%
maximum weekly ET p over three applications per week (M-W-F).
Conservative: 125% weekly ET p adjusted by month, over three
applications per week (M-W-F). If rain event = 8.4mm of rain, then
next irrigation was voided.If rain event = 8.4mm of rain, then next
irrigation was voided.
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- ET p calculated (McCloud, 1955) ET P = KW (T-32) Where: K =
0.01 W = 1.07 T = mean temperature in o F. Over predicts ET during
temperatures > 70 o FOver predicts ET during temperatures >
70 o F Uses a daily ET limiter of 7.6mm (Stewart and Mills,
1967)Uses a daily ET limiter of 7.6mm (Stewart and Mills,
1967)
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- ET Models ET Models M= McCloud P= Penman T= Thornwaite From
Augustine, 1983 Comparison of methods for calculating ET p for
Miami, Florida
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- Exp. I: M&M 4 N Sources Liquid Water soluble Urea (46%N) in
0.25 L H 2 0 /m 2 Granular Water soluble Urea (46%N) Granular Water
soluble + controlled-release 50% Urea (46%N) + 50% SCU (39%N)
GranularControlled-release SCU (39%N) UREA SCU
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- Exp. II: M&M 3 N Rates Applied bimonthly Year total
----------------------------- (kg N ha -1 ) -----------------------
25 25150 50 50 100 100300600
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- Exp. I: Observations & Measurements: 1. Water budget:
Irrigation Irrigation Rainfall Rainfall ETp ETp Percolate Percolate
Percolate = Rainfall + Irrigation ET (Snyder et al., 1984)
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- Exp. I:Observations & Measurements: 3. Growth: Dry weights
Dry weights Clippings from a 2m 2 area Clippings from a 2m 2 area
Tissue N analysis Tissue N analysis 0-15cm and 15-30cm cores 0-15cm
and 15-30cm cores 2. Visual turfgrass quality: Scale from 1-10
Scale from 1-10
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- Exp. I:Observations & Measurements: 4. NO 3 -N
concentrations and leaching Vadose zone pore water collected when
percolate is predicted Vadose zone pore water collected when
percolate is predicted Flow injection analysis using a Cd-Cu
reduction column Flow injection analysis using a Cd-Cu reduction
column Total cycle loadings Total cycle loadings Average cycle
loadings Average cycle loadings Annual loadings Annual loadings
Daily loadings = [NO 3 -N] X percolate volume Daily loadings = [NO
3 -N] X percolate volume (over 24h) (over 24h)
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- Exp. I: Observations & Measurements: 5. Percent N leached
of applied N Cycle Cycle Annual Annual
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- EXP. II: M&M Irrigation treatments (2) Excessive: 125%
weekly ET p adjusted by month, over three applications per week
(M-W-F). If rain event = 8.4mm of rain, then next irrigation was
voided.If rain event = 8.4mm of rain, then next irrigation was
voided. Conservative: Irrigate as above when visual wilt is
present.
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- Exp. II: M&M N Sources No fertilizer Water soluble 100%
Urea (46%N) Water soluble + controlled-release 50% Urea (46%N) +
50% SCU (39%N) Water soluble + slow-release 25% Urea (46%N) + 75%
IBDU (31%N) Water soluble + slow-release 50% Urea (46%N) + 50% IBDU
(31%N) Water soluble + slow-release 75% Urea (46%N) + 25% IBDU
(31%N) IBDU UREA SCU
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- Exp. II: M&M 2 N Rates Applied bimonthly Year total
---------------------------------- (kg N ha -1 )
----------------------- 25* 25*150 50 50300 * = 50% UREA/ 50% SCU
will not be tested at this rate.
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- Exp. II: Observations & Measurements: Water Budget Water
Budget Visual turfgrass quality Visual turfgrass quality Growth
Growth N tissue analysis N tissue analysis NO 3 -N concentrations
and leaching NO 3 -N concentrations and leaching Percent N leached
of applied N Percent N leached of applied N Visual turfgrass wilt
Visual turfgrass wilt
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- Statistical analysis General linear modelGeneral linear model
SAS Inc. softwareSAS Inc. software
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- Anticipated Results Different combinations will result in
different N leaching amounts and turfgrass quality
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- Implications Less demand on water supplyLess demand on water
supply Greater water use efficiencyGreater water use efficiency
Reduce risk of contamination to ground water supplyReduce risk of
contamination to ground water supply Basis for new BMPs for St.
Augustinegrass in South FloridaBasis for new BMPs for St.
Augustinegrass in South Florida
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