Final - Soil water Flashcards
What above all else contributes to soils hydrological properties?
the clay fraction
Define porosity
the fraction of total soil volume that is air and water
define volumetric water content
the fraction of soil volume that is water
define gravimetric water content
the mass fraction of water in the soil. The water freely available to drain by gravity
explain hygroscopic, capillary, and gravitational water
hygroscopic water is held tightly to soil. Capillary is suspended but not as tight. Gravitational water flows down freely.
how is porosity related to volume?
greater pore volume (like in clay) = greater porosity
define field capacity
the water in a soil that can be retained against gravity through absorbed water and capillary pressure
define permanent wilting point
water content at which plants can no longer draw water from the soil.
what are the two types of infiltration
ponded and non-ponded
what are the three types of flow?
- macropore
- funnel
- fingering
define hydraulic conductivity
how effectively water moves through a substrate under a given hydraulic gradient.
how do plants draw water up?
- osmotic pump pulls water into roots overnight
2. evapotranspiration creates suction forces during day
