GEOG 1280 Lecture Notes - Lecture 50: Porosity, Field Capacity, Permanent Wilting Point
17 May 2017
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Document Summary
Pore space, sand (large size), clay (small size) Linked pores deals with the movement of water 3) vegetation and organisms. How much rainfall in an hour, high intensity = exceeding infiltration capacity 5) rainfall duration. Number of hours of rain, saturation occurs 6) time since last rain. Days in a row with rain leads to saturation or without leads to powdered surface that acts like a barrier. Deforestation: crops and agriculture practices o grazing. Hygroscopic water: 1 molecule thick layer 31 to 10,000 atmosphere vapour movement only. Thinly attached to particles, taking water away is difficult. Capillary water 31 to 1/3 atmosphere can move in the soil through capillary action. Field capacity 1/3 atmospheric pressure, water moves through system. Fine soils and high organic soils have higher field capacity. Gravity water flows with gravitational gradient <1/3 atmospheric pressure. Wilting point: pressure a plant can exert to pull water approximately 15 atmo.
