Search results
Results from the WOW.Com Content Network
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.
The first modern theoretical models for soil consolidation were proposed in the 1920s by Terzaghi and Fillunger, according to two substantially different approaches. [1] The former was based on diffusion equations in eulerian notation, whereas the latter considered the local Newton’s law for both liquid and solid phases, in which main variables, such as partial pressure, porosity, local ...
[15] k 1 is the rate constant for chemical uptake from water at the respiratory surface (L*kg −1 *d −1). [15] C WD is the chemical concentration dissolved in water (g*L −1 ). [ 15 ] k 2 ,k E ,k G ,k B are rate constants that represent excretion from the organism from the respiratory surface, fecal excretion, metabolic transformation, and ...
A relatively low rate of change indicates when macropore drainage ceases, which is called Field Capacity; it is also termed drained upper limit (DUL). Lorenzo A. Richards and Weaver [5] found that water content held by soil at a potential of −33 kPa (or −0.33 bar) correlate closely with field capacity (−10 kPa for sandy soils).
The maximum rate at that water can enter soil in a given condition is the infiltration capacity. If the arrival of the water at the soil surface is less than the infiltration capacity, it is sometimes analyzed using hydrology transport models , mathematical models that consider infiltration, runoff, and channel flow to predict river flow rates ...
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]
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 soil moisture velocity equation consists of two terms. The first "advection-like" term was developed to simulate surface infiltration [ 4 ] and was extended to the water table, [ 5 ] which was verified using data collected in a column experimental that was patterned after the famous experiment by Childs & Poulovassilis (1962) [ 6 ] and ...