Moisture equivalent is proposed by
Lyman Briggs and McLane (1910) as a measure of
field capacity
Field capacity is the amount of soil moisture or water content held in the soil after excess water has drained away and the rate of downward movement has decreased. This usually occurs two to three days after rain or irrigation in pervious soils of ...
for fine-textured soil materials.
Moisture equivalent is defined as ''the percentage of water which a soil can retain in opposition to a centrifugal force 1000 times that of gravity''. It is measured by saturating sample of soil 1 cm thick, and subjecting it to a centrifugal force of 1000 times gravity for 30 min. The gravimetric water content after this treatment is its moisture equivalent.
This concept is no longer used in
soil physics
Soil physics is the study of soil's physical properties and processes. It is applied to management and prediction under natural and managed ecosystems. Soil physics deals with the dynamics of physical soil components and their state of matter, ...
and has been replaced by field capacity.
Lyman Briggs and
Homer LeRoy Shantz (1912) found that:
Moisture Equivalent = 0.02 sand + 0.22 silt + 1.05 clay
Note: The volume of water stored in the root zone is equal to the depth of water in the root zone (Vw=Dw)
See also
*
Available water capacity Available water capacity is the amount of water that can be stored in a soil profile and be available for growing crops. It is also known as available water content (AWC), profile available water (PAW) or total available water (TAW).
The concept, p ...
*
Field capacity
Field capacity is the amount of soil moisture or water content held in the soil after excess water has drained away and the rate of downward movement has decreased. This usually occurs two to three days after rain or irrigation in pervious soils of ...
*
Nonlimiting water range The non-limiting water range (NLWR) represents the range of water content in the soil where limitations to plant growth (such as water potential, air-filled porosity, or soil strength) are minimal. John Letey (1985) from UC Riverside introduced the ...
*
Pedotransfer function
*
Permanent wilting point
Permanent wilting point (PWP) or wilting point (WP) is defined as the minimum amount of water in the soil that the plant requires not to wilt. If the soil water content decreases to this or any lower point a plant wilts and can no longer recover ...
References
*
*
* {{cite book , last = Lyman , first = James Briggs , author-link = Lyman James Briggs , author2=H. L. Shantz , title = The wilting coefficient for different plants and its indirect determination , publisher = USDA Bureau of Plant Industry , year = 1912 , id = Bulletin 230
Soil physics
Equivalent units