SVERIGES LANTBRUKSUNIVERSITET - Epsilon Open Archive - SLU

-40.0
.-,.-30.0
:. - 20.0
:E - 10.0
-ca .- .... c
el) ....
o
o.
...
el)
....
ca
==
-2.5
Fig.4
A
1
B c D E
I I
Soil Root Stem Leaf Atmosphere
Idealized water potential gradients through the SP AC. Curves 1
and 2 represent plant water removal from relatively wet soil at
low and high transpiration rates, respectively; curves 3 and 4
represent plant water removal at low and high transpiration
rates, respectively, af ter soil water potential has been reduced to
-0.6 MPa. (Af ter Hillel, 1980).
where qr' VJrsm' VJM' k s ' rroot and rcyl are the rate of root water uptake, the
soil matric potential at the root sunace, the bulk soil matric potential, the
hydraulic conductivity of the soil, the radius of the root, and the radius of
the cylinder of soil through which water is moving, respectively. This model
(eq. 8) describes radial transport of water to the root surface from the
cylinder of soil effectively occupied by a root.
4
2
3
1
53