??? ????? ?????? SOIL WATER POTENTIAL

1
??? ????? ??????SOIL WATER POTENTIAL
????? ??????
2
??? ????? ?????? Water potential

• ???? ????? ?????? ???? ???? ????? ?????? ????
  ?????? ??? ???? ?????? ?? ????? ??? ????? ??
  ??????? ??????? ??? ???? ???????. (?? ??????
  ?????? ????? ????? ?????) ??? ??? ???? ???????.
• ??????? ??????? ???? ??????? ??? ??? ??? ?? ???
  ????? ????? (????? ????? ??????).

3
???? ??????? ?? ??? ????? ??? ????? ?????? ???????

• ??? ???? ?????
• Energy/Volume (ML2T-2)/ (L3) ML-1T-2
• ??? ????? ????? ????? ??? ??? ?????? ????
  ??????? Pa, Kg m-1s-2, Jm-3
• ??? ???? ??????
• Energy/mass (ML2T-2)/ (M) L2T-2
• ????? ???? ????? JKg-1 , m2s-2.
• ??? ???? ????? Weight basis
• ??? ?? ????? ????? ?? ???
• Energy/Weight (ML2T-2) / (MLT-2) L
• ????? ???? ????? ????? (m).
• ?? ?????? ????? ??????? ???????? ?? ?????.
• ???? ?? ????? ?? ??? ?????? ??????? ???? ?????.

4
????? ??????? ??? ??????? ????????
???????? ????? ??????? ??????? 1 bar 100 cb
1000mb 1022 cm water 1000
H2O 75.01 cm Hg 0.9869
atom or 1 atom 100 J Kg-1 106 erg
gm-1 106 dyne cm-2
5

• ????? ?? ??? ????? w ? ?????? ??????? ??????
• ?w ?p ?m ?s
• ???
• ?p ???? ??? ??? ????? ??? ?????? ??????? ??????
  ????? (?????? ?????).
• ?m ???? ??? ??? ???? (????? ??????) ??? ????????
  ????? ?????(???? ?????).
• ?s ???? ??? ????? ???????? ????? ????? ??? ???
  ???????? ??????? ?? ????? (??? ?????? ????????).
• ????? ????? ????? ????? (?t) ????? ?? ????? ???
  ????? ????? ???? ??? ???????? ??????? (?g).
• ?t ?w ?g

6
??? ???????? ??????? Gravitational Potential

• ???? ??? ???????? ???????.
• Eg m g z
• ???
• Eg ???? ??? ???????? ??????? ?
• g ???? ???????? ? z ???????? ? m ????
  ?????

7
??? ???????? ??????? ?? ????? ?? ????
????? ?? ?????? ?????? ?????? ?????? ?? ?????
???? ??????? ???? ???? ?????? ?????? ????? ?????
??? ??????? ??????? ??? ?????? ???? ????? ?????
?????? ?? ???? ?????? ??? ??????? ??????? ???
?????? ???? ????? ????? ??? ?? ????? ??????
???????

??? ??????? ???????
Ref g z
Ref - g z
??? ??????? ???????
- ???????
8
??? ????? Pressure Potential
??? ?? ???? ????? ???? ????? ?????? ??? ???
???????????? ???? ?? ????? ????? ????? ??? ?????
???????? ??? ??? ??? ?? ???? ??? ??? ??? ????
????? ???? ??? ??? ????? ??? ??? ????? ?????
(???) ?????? ?????????????? (P) ????? ???????
????? ????? ???? P ?w g h ???
?w ????? ????? ? h ??? ?????? ??? ??? ?????
????. ????? ???? ??? ????? Ep ?????? Ep
P(dv) ?w g h (dv)
9

• ???? ???? ???? ????? ???? ??? ????? ?p ??????
• ?p h
  
• ????? ???? ???? ?????? ?? ????? ????? ???? ???
  ???? ????? ???? ??? ????? ????? ?? ?????? ???
  ????? ???? ??? ?????? ?????? ????? ????? ??
  ??????.
• ???? ????? ?? ??????? ??????? ?? ?????? ????
  ????? ???? ????????? Piezometers.

10
(No Transcript)
11
??? ???? (????? ??????)

• ??? ????? ??????? ???? ???????? ? ??????? ???????
  ???????.
• ???? ????? ???? ????? ?????? ? ???? ?? ???? ????.
  
• ????? ??? ??? ???? ?m ??? ???? ???? ????? ??
• ?m - h
• ?? ?????? ???? ????? ?? ??????? ??????? ???
  ?????? ?????? ?????? ???? ??? ????? ???? ????????
  ????? ?????? ????? ???? ?????? ?? ???? ??? ?????
  ???? ????? ???? ??? ???????.

12

13

14

• ???? ???? ???? ?? ????? ????? ???????? ?? ???????
  ???????.
• ???????? ?????? ??? ???? ???? ????? ?????? ?????
  ?? ????? ?????? ???????? ????????? ??????.
• ??? ?? ?????? ?????? ?????? ????? ???? ????????
  ?? ????? ?????? ????.

15

• ??? ??????? ??????? ???? ????? ??????? ?? ???????
  (???- 100) ???? ????? ??? ?? ?? (??? 1000 ??).
• ?? ?? ?? ????? ???? ???? ??????? (cb) ????? ?????
  (??? 1000) ???? ??? ???? ????? ?? ????? ?????
  ???? ???????(mb).
• ???? ???? ??? ????(?m) ??????? ??? ???
• ?m - (RN) Z0
• ???
• R ?? ????? ???? ????? ???????.
• N ????? (????) ??? ??? ??????? ???? ????
  ???.mb
• N ????? 10 (????) ??? ??? ??????? ???? ?????
  ??? .cb
• ???? ???? ?m ??????? ????? ?? ???????? H2O
  cm.
• Z0 ?? ????? ?????? ?????? ??????? ?? ?????
  ?????????? ???????.

16
????? ??????? ????? ??????? ??????????? ???????
Mercury manometer ????? ???? ??? ???? ??????
?Hg ?H2O ?H2O
?m -ZHg Z0

• ???
• ?Hg ????? ?????? ?????? 13600 ??? ?-3.
• ?H2O ????? ????? ?????? 1000 ??? ?-3.
• Z ????? (ZHg Z0) ? ????? ????????? ???????? ??
• ?m (-12.6 ZHg) Z0
• ??? ZHg ?? ?????? ?????? ?? ?????????? ??? ?????
  ?????? ????? ?????.

17
????? ????????

• ????? ?????? ?????? ??????? ?????? ??????.
• ????? ?? ???? ????? ?????? ?? ???? ???? ?????
  ??????? ????? ??????.
• ????? ???????? ????? ????? ????? ???.
• ???? ???? ????? ??? ???? ?????? ???????? ?????
  ?????? ?????? ???? ??????? ??????? ??????????
  Thermo Cupple Psychrometer ????? ??????? ??????.
• ???? ??? ????? ???? ????? ????? ???? ???? ?????
  ???????? ???????.
• ?? ??? ?????? ???? ??? ??? ?????? ?????? ??????
  ????? ???????? ???? ????.
• ????? ???????? ?? ???? ????? ?????? ?? ???????
  ??? ???????.
• ????? ???????? ??? ??? ?? ???? ???? ????? ???
  ??????? ????? ?? ????? ?????? ?? ?????? ??????.

18
?????????????? ?????? ?????
?? ???? ???? ?? ????? Tensiometer ?? ????
????? ???? ?? ??? ??? 100 ???? ??????? 31 ????
?????? ?????? ????? ??????? ??????? ?? ???????
??? ????? ?????????? 80 ?? ???????? ???? ?-
??? ????. ?- ?????? ?????? ???? ?????????? ?? ??
??????? ?????? ????????? ?????.
19

• ????????????
• ????? ??? ????
• ?m -R x N) Z0
• ?m -(31 x 10) 80 -310 80
• -230 cm H2O
• -0.23 bar
• -23 K Pa
• ??? ?? ???? ????? ??????? (0.1 0.3 bar)
  or (10 33 KPa)
• ????? ?????? ?????? ???? ?????????? ???????
• ?m (-12.6 ZHg) Z0
• -230 (-12.6 ZHg) 80
• ZHg (-230 80) / (-12.6) -310 /-12.6
• 24.6 cm Hg