Exam 2 Flashcards
Types of water erosion
- sheet
- Rill
- Gully
- Stream bank
Sheet Erosion
uniform removal of thin layers of soils over the whole soil surface.
Rill Erosion
small visible erosion channels that can be erased by normal tillage operations
Gully Erosion
Erosion channels to large to be erased by normal tillage operations.
-Ephemeral Gullies
Ephemeral Gullies
Natural water courses that can persist even after large scale mechanical fillings
Active Gully
Bare vertical walls
little vegetation
active head cutting
Inactive gully
Vegetated, somewhat rounded walls, no head cutting.
Stream bank Erosion
Usually around outside bends, moves material a long distance from origin
Water Erosion Damage
- Soil loss
- Nutrient loss
- Texture change
- Soil Structure Damage
- Productive capacity is reduced
- Field Dissection
- Engineering Structure damage
- Water Pollution
- Siltation of lakes and stream channels.
Terminal velocity
- maximum speed of falling against air resistance
Energy of water
-Falling raindrops have more energy than running water
Principles of water erosion control
- reduce raindrop impact on the soil
- reduce runoff volume and velocity
- increase the soils resistance to erosion
Types of soil movement
- Suspension
- Saltation
- Surface creep
damages of wind erosion
- loss of soil
- Textural changes
- Nutrient loss
- Abrasion
- Air Pollution
- Deposition
factors effecting wind
- Soil resistance
- surface ridges
- climate
- topography
- length of exposed area
- vegetative cover
principles of wind erosion control
- reduce wind velocity at ground level
2. remove abrasive material from s
universal soil loss equation
A=RKLSCP
A
estimated average annual soil loss
R
Rainfall and runoff factor (rt snowmelt runoff)
K
Soil erodibility factor
LS
slope length factor
Wind erosion equation
E=f(I’,k’,c’,l’,v)
I’
Potention soil loss in T/ac/yr from isolated field with bare smooth non crusting surface.
row crops
open bare areas between rows
small grain
between plantings
companion/nurse crop
Erosion control or soil crustin
cover crops
for protecting the soil by filling in the gaps in time or space when other crops are not there
Green manure
tilling in of live crops for the benefits of increasing soil organic matter content. Green! not dead! Soil structure, soil permeability, soil fertility
multiple croping
two or more crops in a single year
- small grains then corn or hay
- corn or potatoes-fall peas forrage
Soil structure
as soil structure gets weaker soil tilth goes down (harder to till) soil permeability is lower (more ponding and soil runoff) soil watering holding capacity is lower, CEC is lower ( holds less nutrients) .
surface residue
helps for water erosion control. organic matter works like glue to reduce it.
companion/nurse crop
Erosion control or soil crusting
multiple cropping
two or more crops in a single year
- small grains then corn or hay
- corn or potatoes-fall peas forage
surface residue
helps for water erosion control. organic matter works like glue to reduce it.
What does tillage do?
- it breaks down the soil structure
- it decreases the organic matter
soil conditioning rating indices
numbers system that accounts for conservation effort that sees if there is a positive or negative affect on the soil.
Threshold Velocity
the minimum velocity of the wind to cause soil movement
Avalanching
Increasing rate of wind erosion as the wind moves farther across the field. More material is added as it blows across the field
Rating indices
to mesure if something is improving, maintaining or deteriorating a soil.
