Final Study Guide - Soil Degradation Flashcards
Soil health is the continued capacity of soil to function as a ____ living ____ that sustains plants, animals, and humans (NRCS)
vital, ecosystem
A healthy soil is characterized by:
a) High infiltration, high permeability and high runoff rates
b) High infiltration, high permeability and low runoff rates
c) High infiltration, low permeability and high runoff rates
d) Low infiltration, high permeability and high runoff rates
b) High infiltration, high permeability and low runoff rates
A healthy soil is characterized by:
a) High diversity but low biological activity
b) High nutrient supply and low nutrient retention
c) Low nutrient supply and low nutrient retention
d) High nutrient supply and high nutrient retention
d) High nutrient supply and high nutrient retention
Define soil degradation
The reduction in capacity of the soil to support life, through the damage to important physical, chemical, and biological properties
The major cause of soil degradation worldwide is:
a) Leaching of nitrate
b) Chemical spills
c) Climate change
d) Soil erosion
e) Overgrazing
d) Soil erosion
Semiarid and Mediterranean regions are subjected to soil degradation through:
a) Water erosion
b) Wind erosion
c) Salinity
d) Sodicity
e) All of the above
e) All of the above
What are the three types of water erosion?
Sheet erosion
- homogeneous, causes most soil loss
Rill erosion
- Initiated when the water concentrates in small channels (rills) as it runs off the soil. Can be smoothed through tillage
Gully erosion
- Creates deep channels that cannot be erased by cultivation
What are the three mechanisms of transport of soil particles by wind? Which one is the predominant?
Suspension, saltation, and soil creep
Saltation is the predominant one
What is suspension?
What percentage of total movement does it take up?
Fine sand and smaller particles move parallel to the ground and upward
15% of total movement
What is saltation?
What percentage of total movement does it take up?
Medium size particles make short bounces across the soil surface
50-90% of total movement
What is soil creep?
What percentage of total movement does it take up?
Larger particles roll/slide across soil surface
5-25% of total movement
Which of the following strategies can prevent soil erosion by water?
a) Contour cultivation
b) Intercropping
c) No-till
d) Mulching
e) All of the above
e) All of the above
Bacteria and bacterial-based food webs are promoted through no-till (true/false)
True
What are the three principles of healthy soil management?
- Minimize soil disturbance
- Maximize soil cover
- Promote biodiversity
What soil conservation practice fulfills all of the principles?
Cover cropping
