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Victor E. Cabrera*, Peter E. Hildebrand, and James W. Jones. El Niño-Southern Oscillation Impact on Nitrogen Leaching in North Florida Dairy Forage Systems. Introduction. N in water affects human health and ecosystem welfare Increased N levels in Suwannee river basin - PowerPoint PPT Presentation
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El Niño-Southern Oscillation Impact on Nitrogen Leaching in North Florida Dairy Forage Systems
Victor E. Cabrera*, Peter E. Hildebrand, and James W. Jones
• N in water affects human health and ecosystem welfare
• Increased N levels in Suwannee river basin
• Dairy farming is thought to be an important factor
• Evidence indicates forages systems are the main means of N recycle
Introduction
Introduction
• Improvements in climate forecast can help devise management strategies
• Data on time-series experiments in Tifton, GA and in North Florida Holstein, Gilchrist, FL
• Crop models (DSSAT v4.0) were used to experiment N leaching spatially and temporally
Introduction
• Assess the potential N leaching from forage systems under intensive application of dairy manure• Capacity of forages to uptake N• Risk of N leaching under different:
• Climate• Crop systems• Soils
Objectives
• Survey and focus groups• Soil series (SSURGO)• Climate-ENSO phases• Crop systems• Manure N application• Crop simulations • Outputs: data 56-98
Materials and Methods
• Crop systems
Results and Discussion
MAR APR MAY JUN JUL AUG SEP OCT NOV DEC JAN FEB MAR
PERENNIAL PEANUT* **
FALL - WINTERCORN
BERMUDA GRASSBAHIA GRASS
SORGHUMMILLETCORN
RYEOATS
WHEATSORGHUM*
MILLET*BERMUDA GRASS
BAHIA GRASS
SPRING - SUMMER SUMMER - FALL
RYEGRASSCLOVER**
• Calibration and validation of DSSAT models• Bahia grass – Bermuda grass• Corn, sorghum, millet, winter forages
Results and Discussion
0.00
2.00
4.00
6.00
8.00
10.00
12.00
132 N 174 N 228 N 132 N 174 N 228 N 132 N 174 N 228 N
1996 1996 1996 1997 1997 1997 1998 1998 1998
Mg/
ha Observed
Simulated
Sorghum
Results and Discussion
• Sensitivity analyses
0.00
2.00
4.00
6.00
8.00
10.00
12.00
14.00
16.00
18.00
20.00
0 70 140 280 420 560 700
MANURE N APPLIED (Kg Ha -1)
BIO
MAS
S (M
g Ha
-1)
0
10
20
30
40
50
60
70
80
N LE
ACHE
D (K
g Ha
-1)
BIOMASS
N LEACHED
CORN
Results and Discussion
• N leaching by ENSO phase All Years La Niña Neutral El Niño N Leach CV N Leach CV N Leach CV N Leach CV DEC 10.59 98% 13.15 93% 7.69 80% 15.64 127% JAN 108.42 32% 83.19a 35% 108.90b 30% 127.35c 21% FEB 78.57 24% 84.22a 9% 79.94ab 29% 71.60b 20% MAR 20.86 49% 23.54 56% 20.55 42% 19.28 45% APR 5.81 97% 4.90 78% 6.42 71% 5.45 70% MAY 12.18 73% 12.39 103% 12.94 59% 10.61 72% JUN 23.22 43% 22.01 45% 25.13 38% 20.69 50% JUL 16.65 44% 18.42 33% 17.09 48% 14.33 37% AUG 17.05 40% 16.99 40% 15.65 38% 19.71 36% SEP 21.22 39% 19.34 44% 20.33 34% 24.50 39% OCT 20.27 33% 19.02 35% 20.79 36% 20.35 21% NOV 7.00 59% 5.11 42% 7.47 58% 7.75 62% YEAR 341.84 322.29 342.90 357.25
Results and Discussion
• N leaching by ENSO phase
0.60
0.70
0.80
0.90
1.00
1.10
1.20
1.30
1.40
1.50
DEC JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV
RE
LAV
IVE
N L
EA
CH
ING
La Niña
Neutral
El Niño
Results and Discussion
• N leaching by ENSO phase
Results and Discussion
• N leaching by ENSO phase
Results and Discussion
• Precipitation by ENSO phase
Results and Discussion
• Temperature by ENSO phase
0
5
10
15
20
25
30
35
274
286
298
310
322
334
346
358 4 16 28 40 52 64 76 88 100
112
124
136
148
160
172
184
196
208
220
232
244
256
268
Day of the Year (DOY)
Tem
pera
ture
(C)
La Niña
El Niño
Neutral
La Niña years: 55,56,64,67,70,71,73,75,88,98
MaximumTemperature
El Niño years: 57,63,65,69,72,76,82,86,87,91,97
MinimumTemperature
Neutral years: 58,59,60,61,62,66,68,74,77,78,79,80,81,83,84,85,89,90,92,93,94,95,96
Results and Discussion
• Solar Radiation by ENSO phase
0
5
10
15
20
25
274
286
298
310
322
334
346
358 4 16 28 40 52 64 76 88 100
112
124
136
148
160
172
184
196
208
220
232
244
256
268
Day of the Year (DOY)
Sola
r Rad
iatio
n (M
J m
-2 d
-1)
La Niña
El Niño
Neutral
Results and Discussion
• N leaching by ENSO phase
Results and Discussion
• N leaching by ENSO phase
Results and Discussion
• Biomass by ENSO phase All Years La Niña Neutral El Niño Biomass CV Biomass CV Biomass CV Biomass CV DEC 86 32% 102 30% 77 28% 92 41% JAN 1,367 17% 1,563a 13% 1,319b 14% 1,301b 22% FEB 2,292 10% 2,343a 11% 2,346a 7% 2,151b 9% MAR 1,439 28% 1,329ab 23% 1,561a 30% 1,297b 14% APR 959 35% 1,094 28% 938 32% 883 27% MAY 4,546 12% 4,691 7% 4,487 16% 4,533 7% JUN 4,908 13% 4,997 9% 4,818 19% 4,997 9% JUL 3,232 13% 3,280 9% 3,173 18% 3,300 8% AUG 1,649 27% 1,660 16% 1,654 20% 1,631 28% SEP 2,784 11% 2,821 10% 2,811 10% 2,704 12% OCT 3,127 12% 3,211 15% 3,060 11% 3,180 9% NOV 811 49% 833 63% 754 51% 899 44% YEAR 27,202 27,924 26,999 26,968
Results and Discussion
• Biomass by ENSO phase
0.80
0.85
0.90
0.95
1.00
1.05
1.10
1.15
1.20
DEC JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV
REL
AVIV
E B
IOM
ASS
La Niña
Neutral
El Niño
Results and Discussion
• N leaching by crop sequences
0.00
0.50
1.00
1.50
2.00
2.50
MAR APR MAY JUN JUL AUG SEP OCT NOV
RE
LATI
VE
N L
EA
CH
BE-BE
CO-SO
MI-CO
SO-CO
MI-SO
SO-MI
CO-CO
CO-MI
CO-BA
CO-BE
BA-BA
Results and Discussion
• N leaching by soil types
0.00
0.50
1.00
1.50
2.00
2.50
DEC JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV
RE
LATI
VE
N L
EA
CH SOIL1
SOIL2SOIL3SOIL4SOIL5SOIL6SOIL7SOIL8SOIL9SOIL10
6.04
Conclusions
• Higher (lower) nitrogen leaching (biomass accumulation) is predicted for El Niño years than Neutral years and than La Niña years
• This is attributed mostly to the rainfall events and their intensity
Conclusions
• An attempt to correlate the leaching with the Japan Meteorological Index, which is used to predict the El Niño Southern Oscillation phases, showed little correlation.
Conclusions
• Winter in general, and January and February in specific, are the critical months for nitrogen leaching at the same time that low biomass accumulation is noticed.
Conclusions
• The best forage systems to prevent nitrogen leaching are those that start in spring with Bermuda or corn; have in summer Bermuda, Bahia or corn; and finish with winter forages.
• The systems that leach the most are those that include millet and/or sorghum.