Section 6-Soil Stabilization

Question 1

Soil stabilization combines with _________ to be the _________practice that limits or controls erosion.

Answer 1

runoff management, site managment

Question 2

Vegetative measures-______(K factor) #200 sieve fraction and ________should be inventoried for the site plan plans prepared to account

Answer 2

soil types, plasticity

Question 3

Trees and shrubs provide good erosion control. T/F

Answer 3

F -do little for erosion unless mature with leaf litter

Question 4

What types of plant materials provide good erosion control?

Answer 4

Fibrous plant material, grasses, legumes, groundcover prevent overland flow.

Question 5

Benefits of Mulching (4 reasons)

Answer 5

conserves moisture and regulates temperature fluctuations, reduces runoff, controls weeds, helps establish plant cover on soils subject to erosion

Question 6

Fertilizer main componants-NPK stands for

Answer 6

Nitrogen (N), phosphorus (P), Potassium (K), listed in order N-P-K.

Question 7

Biotechnical protection measures

Answer 7

use of live cuttings/dormant woody plant materials for soil stabilization.

Question 8

Biotechnical protection measures are often used in combination of structural methods. T/F

Answer 8

T

Question 9

Advantages of Biotechnical protection (8 items)

Answer 9

1. less expensive than structural methods
2. specialized installation skills not required
3. heavy equipment not required
4. environmentally compatible
5. natural aesthetic appearance
6. wildlife habitat and cover
7. self repairing
8. use natural/native materials

Question 10

Disadvantage of Biotechnical protection (8 items)

Answer 10

1. less control vs. structural methods
2. higher maintenance attention
3. establishment period
4. sensitive to seasonal changes

Question 11

Fertilizer 5-10-5 at 40 lbs means how many lbs per

Answer 11

N(5%)=2 lbs per 40 lbs
P(10%)=4 lbs per 40 lbs
K(5%)=2 lbs per 40 lbs

Question 12

Principles of biotechnical slope protection

Answer 12

both structural or mechanical element with vegetative elements. Structural-allow establishment and protection. Vegetative-prevent erosion by protecting surface and stabilizing through root mass.

Question 13

Structural measure of biotechnical

Answer 13

protect toe of face of slope against scour or erosion from moving water. Resists much higher lateral earth pressure and shear values. Natural or manufactured material. Retaining walls, grade stabilization structures, slope protection.

Question 14

Planning Considerations for biotechnical slope protection:

1. What is appropriate ______ for specific problem?
2. ______-what type? How much? Source?
3. ________-season for best time to get establishment?
4. make sure adequate mobilization of needed ________
5. __________-account for management of site water, soil conditions, providing site access. Aesthetics, maintenance.

Answer 14

1. method
2. material
3. schedule
4. Equipment
5. Site Characteristics

Question 15

Soil tackifiers or stabilizers

Answer 15

temporary or until final stabilization. Hydraulic application. Site conditions effecting selection include soil type, slope steepness, expected rainfall, and length of time.

Question 16

Fertilizer Calculation Example
20lbs. N needed of ½ acre site
10-10-10 in 50 lb bag
How many bags?

Answer 16

50lbs x .10= 5lbs N per bag
5x=20lbs
X=4 bags

Question 17

Calculating Pure Live Seed (PLS)-

Answer 17

amount of live seed in bulk seed. PLS is proportionally higher then bulk seed. Tag says many things-seed purity and germination percent. To compute, multiply “germination percent” times “purity” and divide by “100.

Question 18

Calculating Pure Live Seed (PLS)-Example
96% gemination
75% purity
$2.50/lb

Answer 18

Ex.
96% germination x 75% purity = 72% PLS
100

Divide Cost per pound by PLS to get cost per pound of PLS

$2.50 per pound = $3.47 per pound PLS
72%