GEOG 3610 Lecture Notes - Lecture 9: Contact Angle, Water Content, Specific Weight
28 Mar 2018
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Document Summary
Water moves from location of higher potential energy to lower. Soil water potential sum of gravitational potential, matric potential and the osmotic potential: water potential of pure water=0. Gravitational potential: gravitational attraction: relative to point in soil or soil surface. Osmotic pressure: solutes affects thermodynamic properties of water and lowers its potential energy, important for interactions between plant roots and soil, typically not considered if soil solution is dilute. Matric potential (components of the soil that make water move through it) Capillarity and adsorption: adsorption: liquid stays on outside of solid; sticks to solid. Vertical distance traveled due to change in pressure. Capillarity and adsorption result in suction and the combined effect is matric potential. Pressures in vadose zone are negative relative to atmospheric. Units (f force pa (n/m2); l is length unit m) =p/ w (p, water pressure f l-2, w, weight density of water f l-3)
