Soil Erosion Flashcards
1
Q
Types of Erosion
A
- sheet - thin layer of soil removed by running water
- rill - small channels formed by running water
- Gully - large channels
- Surface Creep
- slow movement of soil down a slope
- accelerated by saturated conditions, freezing, thawing
- Saltation
- wind causes small soil particles to move on surface in bouncing fashion
- Suspension
- wind carries fine soil particles, fly above the soil surface
- Tillage Erosion
- moves soil from top to bottom of a field creating shallower soils at the top of field and deeper at the bottom
2
Q
How following affects rate of Erosion by Wind
A
- Soil surface roughness decreases erosion
- use wind blocks
- Unsheltered distance - as unsheltered distance increases, erosion increases
- Soil texture
- sand erosion moving by saltation can dislodge silt and clay particles contributing to erosion
3
Q
Erosion impact on
Crop Yield Potential
A
- primary influence is change in properties of the root zone with erosion
- topsoil is highest in
- organic matter,
- nutrients and
- biological activity
- good physical properties
- Erosion decreases topsoil depth
- crop yield potential declines
- topsoil is highest in
4
Q
Erosion impact on
Water Holding Capacity
A
- loss of topsoil can reduce water holding capacity of a soil
- and cause reduced plant avail water
- changes in texture as subsoils are exposed
- could reduce / increase water holding capacity depending on texture
5
Q
Erosion impact on
Nutrient Content
A
- Nutrient content will generally decline with erosion
- loss of organic matter (source of NPS)
- typically retained near surface of soil
- loss of organic matter (source of NPS)
6
Q
Erosion impact on
Infiltration
A
- Erosion will often reduce soils infiltration capacity
- exposed soils typically have less organic matter and more clay
7
Q
Erosion impact on
Water Quality
A
- Water quality of recieving streams, lakes, reseviors impaired from sediment load during erosion
- sediment carries nutrients (NPS) that can cause
- eutrophication
- excessive aquatic growth - weeds, algae
- light penetration declines
8
Q
Erosion impact on
Air Quality
A
- suspension wind erosion can fill air with particulates that reduce air quality
9
Q
Strip cropping
A
- soil detachment reduced
- cropped soil is protected
- slope length of uncropped soil reduced
- Soil Transport reduced
- cropped strips have increased infiltration and retain sediment
10
Q
Contouring
A
- soil detachment reduced
- slope is reduced when runoff moves along contours
- means lower water velocity
- slope is reduced when runoff moves along contours
- Soil Transport reduced
- slope is reduced when runoff moves along contours
- sediment can settle out
- slope is reduced when runoff moves along contours
11
Q
Terraces
A
- Soil detachment reduced
- reduced slope
- increased infiltration
- Soil Transport Reduced
- reduced slope
- often cropped increasing sedimentatio
12
Q
Grassed Waterways
A
- Soil Detachment reduced
- main channel for water is protected from erosion by sod
- Soil Transport reduced
- slowed velocity through sod
13
Q
Row Spacing and Direction
A
- Soil Detachment reduced
- narrower rows allow earlier vegetation cover
- protects surface from wind / rain
- rows with slight slope / contour increases infiltration
- narrower rows allow earlier vegetation cover
- Soil Transport reduced
- narrower rows increase soil roughness
- slight slope along contour reduced amount of runoff
14
Q
Strip Cropping
A
- commonly used to reduce erosion of one crop (corn) with a second crop (forage)
15
Q
Terraces
A
- Terraces are used where slopes are too steep to allow strip cropping or contouring
