Water Flashcards
(34 cards)
Asymmetric shape of water molecules
Dipole
What causes Surface tension?
Hydrogen bonding
What happens to density and volume when water freezes?
Less dense, more volume
Water’s ability to absorb a large amount of heat without much change in temp
High specific heat
When soil pores are filled to the max with water
Saturated
What effects water movement?
Gravity, adhesion, cohesion
Capillary action
Adhesion and cohesion and moved water in any direction
Capillary rise
Loss of water by evaporation
Water potential
High to low
Negative pressure
Tension or suction
What does tension do to water potential
Lowers
What is atm equal to?
.101 MPa
What determines soil water potential?
Gravity, matric forces, osmotic forces
What are matric forces
Adhesion and cohesion
What are osmotic forces?
Dissolved salts
What causes water to spread laterally when soil is moist
Matric potential
What causes fertilizer burn?
High concentrations of salt creates osmotic potential that inhibits water uptake
When soil is saturated, water tension is…
Zero until drainage, plant use, or evaporation
When adhesive and cohesive forces are equal to gravity
Field capacity
Permanent wilting point
Soil moisture content when a plant wilts and can’t recover even with optimal water conditions
Soil texture determines relationship between…
Soil water content and soil moisture tension
Hygroscopic water
Adsorbed water of thin, tightly bound layer surrounding soil particles. Moisture tension is too high
Crystal lattice water
Less available to plants than hygroscopic water and can only be removed by sufficient heat
Available water range
Soil moisture between field capacity and permanent wilting point
