Missouri State University AGN 215 Unit 4 Review questions and answers

Missouri State University AGN 215
Unit 4 Review questions and answers

Adhesion - correct answer ✔✔Attraction of H2O to a solid phase (such as a soil particle)



Cohesion - correct answer ✔✔mutual attraction among H2O molecules (H-Bonding)



Surface Tension - correct answer ✔✔H2O molecules at an air-H20 interface are more strongly
attracted to neighboring H2O molecules (Cohesion) than to a gas phase (air)



Capillarity - correct answer ✔✔Arises from cohesion, adhesion, and surface tension



Soil Water Potential - correct answer ✔✔Comparative measure of the energy stored in soil
water



Gravitational Potential (Ψg) - correct answer ✔✔Energy in water due to force of gravity and
height of water (positive)



Hydrostatic Potential (Ψh) - correct answer ✔✔Energy due to the weight of the water at a given
elevation and pressure (positive)



Matric Potential (Ψm) - correct answer ✔✔Energy due to attraction with soil solids (negative)



Osmotic Potential (Ψo or Ψs) - correct answer ✔✔energy of water due to presence of solutes in
soil solution (negative)

, Soil Water Potential Equation - correct answer ✔✔Water will mover from areas of higher (more
positive) potential to areas with lower (more negative) potential (Ψw = Ψg + Ψh + Ψm + Ψo)



Positive Potential - correct answer ✔✔Pressure/ Push



Negative Potential - correct answer ✔✔Tension/ Pull/ Suction



Soil Moisture Tension - correct answer ✔✔Tightness or tenacity on which water is held on soil



Saturation (S) - correct answer ✔✔Saturated with H2O

0 Bars



Field Capacity (FC) - correct answer ✔✔H2O drained out somewhat due to gravity

Plant available water

-1/3 Bars



Permanent Wilting Point (PWP) - correct answer ✔✔Plants cannot take up H2O

Plant available water

-15 Bars



Hydroscopic Coefficient (HC) - correct answer ✔✔Air-dried soil

Water not available to plants

-31 Bars



Oven dried - correct answer ✔✔10,000 Bars