Table 4. Soil water

Term Symbol (a) Dimension Unit
(a) Symbols such as C, K, and D may have w or h as a subscript if in the same paper they are used for water as well as For heat.
(b) The dimension depends on the units used to describe the driving force, as in the following table.
Total potential L²T­² erg g­¹, joule kg­¹
Osmotic potential O L²T­² erg g­¹, joule kg­¹
Gravitational potential Z L²T­² erg g­¹, joule kg­¹
Matric potential M L²T­² erg g­¹, joule kg­¹
Soil water pressure - ML­¹T­² dyne cm­², bar, cm water, cm Hg
Osmotic pressure - ML­¹T­¹ dyne cm­², bar, cm water, cm Hg
Total pressure - ML­¹T­² dyne cm­², bar, cm water, cm Hg
Hydraulic head H L cm, m
Hydraulic potential Ø L²T­² erg g­¹, joule kg­¹
Water content w - cm³ cm­³, g g­¹
Differential water capacity C M­¹LT² cm² dyne­¹, bar­¹
Hydraulic conductivity K (b) (b)
Permeability k cm², Darcy
Soilwater diffusivity D L²T­¹ cm²sec­¹

Driving force Dimension Hydraulic conductivity
    Dimension Unit
Hydraulic potential gradient LT­² T sec
Hydraulic head gradient LL­¹ LT­¹ cm sec­¹
Pressure gradient ML­²T­² M­¹L³T g­¹ cm³ sec
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