Geoscience Reference
In-Depth Information
Table 4.4
Measured soil water pressure heads
h
(cm)
Height
z
(cm)
t
= 150 days
t
= 160 days
-15
-156
-224
-25
-112
-148
-35
-80
-120
Table 4.5
Laboratory data of soil moisture characteristic and hydraulic
conductivity function
Pressure head
h
(cm)
Water content
θ
(cm
3
cm
-3
)
Hydraulic conductivity
k
(cm d
-1
)
-80
0.375
0.090
-112
0.325
0.016
-120
0.295
0.010
-148
0.175
0.0045
-156
0.150
0.0019
-224
0.050
0.00022
t
Mean conductivity:
h
i
-1
j
h
i
-1
j
+1
j
+
k
i
j
z
k
i
-1
k
j
=
i-
1/2
2
k
i-
1/2
j
+1
k
j
i-
1/2
q
i
j
q
i
j
+1
Soil water flux (Darcy):
(
)
∆
z
h
i
j
h
i
-1
j
h
i
j
-
h
i
j
+1
-
k
j
q
i
j
-
k
j
=
i-
1/2
i-
1/2
extraction
S
∆
z
k
i
+ 1/2
j
q
i
+1
j
k
i
+ 1/2
j
+1
Water balance:
q
i
+1
j
+1
(
θ
(
h
i
j
+1
θ
(
∆
z
=
))
h
i
j
-
q
i
+1
j
q
i
+1
j
+1
h
i
+1
j
h
i
+1
j
+1
q
i
j
+
q
i
j
+1
(
+
)
-
-
S
∆
t
∆
t
2
2
Figure 4.32
Calculation procedure of root water extraction at different depths in the
root zone, using tensiometer measurements. The subscript refers to height level, the
superscript refers to time level. The soil water luxes are based on the Darcy equation
(
4.16
), the water balance on the continuity equation (
4.21
).
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