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Field capacity is characterized by measuring water content after wetting a soil profile, covering it (to prevent evaporation), and monitoring the change soil moisture in the profile. A relatively low rate of change indicates when macropore drainage ceases, which is called Field Capacity; it is also termed drained upper limit (DUL).
Water retention curve is the relationship between the water content, θ, and the soil water potential, ψ. The soil moisture curve is characteristic for different types of soil, and is also called the soil moisture characteristic. It is used to predict the soil water storage, water supply to the plants (field capacity) and soil aggregate stability.
Available water capacity is the amount of water that can be stored in a soil profile and be available for growing crops. [1] It is also known as available water content ( AWC ), profile available water ( PAW ) [ 2 ] or total available water ( TAW ).
Such maps are typically richer in context and show higher spatial detail, yet are not necessarily more accurate than traditional soil maps. Soil maps produced using (geo)statistical technique can also include an estimate of the model uncertainty. [3] An example of a traditional soil map showing soil mapping units, described soil profiles and ...
Summary of hydrologic and physical properties of rock and soil materials as analyzed by the Hydrologic Laboratory of the U.S. Geological Survey 1948-1960. U.S. Geological Survey Water Supply Paper 1839-D. 42 p. De Wiest, R. J. (1966). On the storage coefficient and the equations of groundwater flow.
Pores (the spaces that exist between soil particles) provide for the passage and/or retention of gasses and moisture within the soil profile.The soil's ability to retain water is strongly related to particle size; water molecules hold more tightly to the fine particles of a clay soil than to coarser particles of a sandy soil, so clays generally retain more water. [2]
The Richards equation represents the movement of water in unsaturated soils, and is attributed to Lorenzo A. Richards who published the equation in 1931. [1] It is a quasilinear partial differential equation; its analytical solution is often limited to specific initial and boundary conditions. [2]
Apart from the basic soil composition, which is constant at one location, soil thermal properties are strongly influenced by the soil volumetric water content, volume fraction of solids and volume fraction of air. Air is a poor thermal conductor and reduces the effectiveness of the solid and liquid phases to conduct heat.