Field capacity is the amount of soil moisture or water content held in soil after excess water has drained away and the rate of downward movement has materially decreased, which usually takes place within 2–3 days after a rain or irrigation in pervious soils of uniform structure and texture. Water content or moisture content is the quantity of Water contained in a material such as Soil (called soil moisture) rock, Water content or moisture content is the quantity of Water contained in a material such as Soil (called soil moisture) rock, Soil, often typeset as SOiL, is a four piece rock band from Chicago Illinois United States founded by Shaun Glass Tom Schofield Tim King and Adam Zadel The physical definition of field capacity (expressed symbolically as θfc) is the bulk water content retained in soil at −33 J/kg (or −0. Water content or moisture content is the quantity of Water contained in a material such as Soil (called soil moisture) rock, 33 bar) of hydraulic head or suction pressure. Hydraulic head is a specific measurement of water pressure or Total energy per Unit weight above a Geodetic datum. The term originated from Israelson and West[1] and Frank Veihmeyer and Arthur Hendrickson[2].
Veihmeyer and Hendrickson[3] realised the limitation in this measurement and commented that it is affected by so many factors that, precisely, it is not a constant (for a particular soil), yet it does serve as a practical measure of soil water-holding capacity. Field capacity improves on the earlier concept of moisture equivalent by Lyman Briggs. Moisture equivalent is proposed by Lyman Briggs and McLane (1910 as a measure of Field capacity for fine-textured soil materials Lyman James Briggs ( May 7 1874 &mdash March 25 1963) was an American engineer physicist and administrator Veihmeyer & Hendrickson proposed this concept as an attempt to improve water use efficiency for farmers in California during that time.
Field capacity is characterised by measuring water content after wetting a soil profile, covering it (to prevent evaporation) and monitoring the change in soil moisture in the profile. Water content or moisture content is the quantity of Water contained in a material such as Soil (called soil moisture) rock, A soil horizon is a specific layer in the Soil which measures parallel to the soil surface and possesses physical characteristics which differ from the layers above and Evaporation is the process by which Molecules in a Liquid state (e Water content or moisture content is the quantity of Water contained in a material such as Soil (called soil moisture) rock, Water content when the rate of change is relatively small is indicative of when drainage ceases and is called Field Capacity, it is also termed drained upper limit (DUL). Water content or moisture content is the quantity of Water contained in a material such as Soil (called soil moisture) rock,
Lorenzo A. Richards and Weaver[4] found that water content held at potential of −33 J/kg (or −0. Lorenzo Adolph Richards (1904–1993 or known as Ren was one of the 20th century’s most influential minds in the field of Soil physics. 33 bar) correlate closely with field capacity. Various potentials was also suggested from −1 J/kg for organic soils, −5 J/kg for soils in the UK, −10 J/kg for loamy soils, and −100 J/kg for heavy clay soils.
There are also critiques of this concept: field capacity is a static measurement, in a field it depends upon the initial water content and the depth of wetting before the commencement of redistribution and the rate of change in water content over time. These conditions are not unique for a given soil.
See also
- Available water capacity
- Integral energy
- Nonlimiting water range
- Permanent wilting point
- Pedotransfer function
References
- ^ Israelson, O. Available water capacity or available water content ( AWC) is the range of available water that can be stored in soil and be available for growing crops Integral energy is the amount of energy required to remove water from an initial Water content \theta_i to water content of \theta_f (where \theta_i 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 Permanent wilting point ( PWP) or wilting point ( WP) is defined as the minimal point of Soil moisture the plant requires not to wilt Pedotransfer function ( PTF) is a term used in Soil science literature which can be defined as predictive functions of certain soil properties from other more available W. and West, F. L. (1922). "Water holding capacity of irrigated soils". Utah State Agricultural Experiment Station Bull 183: 1–24.
- ^ Veihmeyer, F. J. and Hendrickson, A. H. (1931). "The moisture equivalent as a measure of the field capacity of soils". Soil Science 32: 181–193. doi:. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document.
- ^ Veihmeyer, F. J. and Hendrickson, A. H. (1949). "The application of some basic concepts of soil moisture to orchard irrigation". Proc. Wash. State Hort. Assoc. 45: 25–41.
- ^ Richards, L. A. and Weaver, L. R. (1944). "Moisture retention by some irrigated soils as related to soil moisture tension". Journal of Agricultural Research 69: 215–235.
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