enviroscan - tool for water management.ppt [read-only]...solar panel fig.1 citrus tree probe....
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Solar Panel
Data Logger
Probes
Cable
Depth cm
10
110
70
20
40
Sensors
Cable Data logger
Solar Panel
Fig.1Citrus Tree
Probe
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EnviroSCAN Probe Installation
The EnviroSCAN probe is installed using specialized tools to minimize disturbance of the soil profile and insure a tight contact between the access tube and the soil.
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SENSORELECTRODES
CABLEACCESSTUBE
EnviroSCAN Probe Design
TOP CAP
ZONEOFCOVERAGE
Fig. 1
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Dielectric ConstantThe dielectric constant of water depends upon the polarization of its molecules in an electric field.The dielectric for :– water = 80– soil matrix < 10– air = 1
The dielectric contant of the SWA mixture is dominated by water-volume fraction
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Capacitance probe can be inserted in PVC access tube or placed directly in the soil.Field results indicated that portable probes were unable to give acceptable soil water content especially for coarse textured and fine sandy loam soils.Air gaps, changes in bulk densities and poor field installation of the access tubes are serious problems with portable probes.
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Fig.2
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Fig.2
Max After Rain
Before Rain
Total Rain = 17 mm (100%)Effective Rain = 12 mm (70%)Interception = 05 mm (30%)
Irrig Eff. =75%
Irrig Eff. =82%
Irrig Eff. =77%
1 hr Irrigation7 mm
2 hr Irrigation14 mm
No Effect beyond 20 cm
4/7/2003 17Depth below the soil surface (cm)
0 20 40 60 80 100 120
Volu
met
ric S
oil W
ater
Con
tent
(%)
4
6
8
10
12
14
02 PM Feb. 108 PM Feb. 101 PM Feb. 211 PM Feb. 2
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WABAMO
Model DescriptionCitrus Evapotranspiration &
Water Leaching
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Evapo-transpiration
Transpiration
Evaporation
Rain
Runoff
Leaching
Root Zone Water Storage
Irrigation
Below RootZone
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Water Mass balance Equation
ET = I + Qv + ∆W
ET = EvapotranspirationI = Rain & IrrigationQ v = Drainage Below Rootzone )W = Soil Water Storage variation between two time steps
ET = I + Qv + W
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20
30
40
50
60
Wat
er C
onte
nt (m
m )
3040506070
0 30 60 90 120 150 180 210 240 270 300 330 3605060708090
100110
Below Root Zone
Root Zone
Total Profile
Calender Day (1997)
Water contentSetting level 1 Setting level 2
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Daily Evapotranspiration for a Young Citrus Grove (1997)
Calender Day 0 30 60 90 120 150 180 210 240 270 300 330 360
Dai
ly E
vapo
tran
spira
tion
(mm
)
1
2
3
4
5
6
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Calculated Cumulative Evapotranspiration for a Young Citrus Grove (1997)
Calender Day 0 30 60 90 120 150 180 210 240 270 300 330 360
Dai
ly E
vapo
tran
spira
tion
(mm
)
200
400
600
800
1000
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Calculated Water Leaching Below a Young Citrus Grove (1997)
Day of the Year0 50 100 150 200 250 300 350
Dai
ly L
each
ing
(mm
)
0
10
20
30
40
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Days of the Month (April 1996)27.0 27.5 28.0 28.5 29.0
Hou
rly
ET
(mm
)
0.0
0.1
0.2
0.3
0.4
0.5
0.61.8 m2 wetting area
16.3 m2 wetting area7.3 m2 wetting area
4/7/2003 26Days of the Month (April 1996)
27.0 27.2 27.4 27.6 27.8 28.0 28.2 28.4 28.6 28.8 29.0
Cum
ulat
ive
Dai
ly E
T (m
m)
0
1
2
3
4
5
61.8 m2 wetting area
16.3 m2 Wetting area
7.3 m2 Wetting area
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Cumulative Leaching Below a Citrus Grove (1997)
Calender Day0 30 60 90 120 150 180 210 240 270 300 330 360
Cum
ulat
ive
Leac
hing
(mm
)
150
300
450
600
750
900