Soil physics

continuous movement of water on, above and below the surface of the Earth

Porosity or void fraction is a measure of the void (i.e. "empty") spaces in a material, and is a fraction of the volume of voids over the total volume, between 0 and 1, or as a percentage between 0% and 100%. Strictly speaking, some tests measure the "accessible void", the total amount of void space accessible from the surface (cf. closed-cell foam).

equation describing the flow of a fluid through a porous medium

thumb|Mānuka honey is an example of a thixotropic material. Thixotropy is a time-dependent shear thinning property. Certain gels or fluids that are thick or viscous under static conditions will flow (become thinner, less viscous) over time when shaken, agitated, shear-stressed, or otherwise stressed (time-dependent viscosity). They then take a fixed time to return to a more viscous state. Some non-Newtonian pseudoplastic fluids show a time-dependent change in viscosity; the longer the fluid undergoes shear stress, the lower its viscosity. A thixotropic fluid is a fluid which takes a finite tim

process by which water on the ground surface enters the soil

area in an aquifer, below the water table

measure of the ability of a porous material to allow fluids to pass through it

the unsaturated aquifer above the water table

potential energy of water per unit volume relative to pure water in reference conditions; the tendency of water to move from one area to another due to osmosis, gravity, mechanical pressure and matrix effects

quantity of water contained in a material

minimum amount of water in the soil that the plant requires not to wilt

measure of the ability of a porous material to allow water to pass through it

thumb|Conceptual model describing the mechanisms of water flow attenuation within a beaver wetland with an unconfined floodplain Ecohydrology (from Greek , oikos, "house(hold)"; , hydōr, "water"; and , -logia) is an interdisciplinary scientific field studying the interactions between water and ecological systems. It is considered a sub discipline of hydrology, with an ecological focus. These interactions may take place within water bodies, such as rivers and lakes, or on land, in forests, deserts, and other terrestrial ecosystems. Areas of research in ecohydrology include transpiration and pla

process of infiltration and percolation of water in the ground and aquifers

amount of soil water content held in the soil after excess water has drained away and the rate of downward movement has decreased

overall density of a granular material, with void space included in the denominator

device used to measure the matric water potential

unit of permeability

the study of soil's physical properties and processes

subsurface layer in which groundwater seeps up from a water table by capillary action

soil -exchange of gases between plant roots and the atmosphere

electronic instrument

hydrodynamic physics demonstration

empirical parameter to predict runoff or infiltration from rainfall excess

Bioclogging or biological clogging refers to the blockage of pore space in soil by microbial biomass, including active cells and their byproducts such as extracellular polymeric substance (EPS). The microbial biomass obstructs pore spaces, creating an impermeable layer in the soil and significantly reducing water infiltration rates.

relationship between soil water content and water pressure head

non-linear partial differential equation that represents the movement of water in unsaturated soils

instrument

thin layer of water surrounding mineral surfaces

measurement technique

In soil, macropores are defined as cavities that are larger than 75 μm. Functionally, pores of this size host preferential soil solution flow and rapid transport of solutes and colloids. Macropores increase the hydraulic conductivity of soil, allowing water to infiltrate and drain quickly, and shallow groundwater to move relatively rapidly via lateral flow. In soil, macropores are created by plant roots, soil cracks, soil fauna, and by aggregation of soil particles into peds. Macropores can also be found in soil between larger individual mineral particles such as sand or gravel.

the amount of water that a portion of an aquifer releases from storage, per unit mass or volume of aquifer, per unit change in hydraulic head

soil type