CPESC Vegetative Stabilization 2 — Questions and Answers
Question 1: What is the minimum recommended seeding rate for tall fescue (Festuca arundinacea) when used as a permanent erosion control cover on disturbed slopes?
- 2-3 lbs PLS/acre
- 4-6 lbs PLS/acre
- 6-8 lbs PLS/acre (Correct answer)
- 10-12 lbs PLS/acre
Correct answer: 6-8 lbs PLS/acre
Tall fescue is typically seeded at 6-8 lbs pure live seed per acre for permanent erosion control applications on disturbed slopes.
Question 2: Which soil amendment is most commonly added to highly acidic soils (pH below 5.5) prior to seeding to promote vegetative establishment?
- Sulfur
- Agricultural lime (Correct answer)
- Potassium chloride
- Gypsum
Correct answer: Agricultural lime
Agricultural lime (calcium carbonate) is applied to raise soil pH in acidic soils, creating more favorable conditions for seed germination and plant growth.
Question 3: A contractor needs to establish vegetation on a cut slope with a 3:1 gradient. Which seeding method would provide the best seed-to-soil contact on this steep surface?
- Broadcast seeding followed by raking
- Hydraulic seeding with tackifier (Correct answer)
- Drill seeding
- Hand broadcasting without incorporation
Correct answer: Hydraulic seeding with tackifier
Hydraulic seeding with tackifier suspends seed in a slurry and adheres it to steep slopes where mechanical incorporation is impractical.
Question 4: What is the primary reason warm-season grasses are preferred over cool-season grasses for erosion control seedings in the southeastern United States during summer?
- They tolerate shade better
- They are drought-tolerant and actively grow during hot summer months (Correct answer)
- They establish faster in wet conditions
- They require less fertilizer
Correct answer: They are drought-tolerant and actively grow during hot summer months
Warm-season grasses like bermudagrass and bahiagrass thrive during summer heat and drought conditions common in the southeastern US, establishing quickly when seeded in late spring.
Question 5: When establishing vegetation on a site with highly compacted subsoil, which practice is most critical BEFORE seeding?
- Applying pre-emergent herbicide
- Deep tillage or scarification to a minimum of 4 inches (Correct answer)
- Installing silt fence downslope
- Applying straw mulch at 2 tons/acre
Correct answer: Deep tillage or scarification to a minimum of 4 inches
Deep tillage or scarification breaks up compaction layers that restrict root penetration, water infiltration, and nutrient availability essential for vegetative establishment.
Question 6: Which cover crop species is most commonly used as a temporary nurse crop in cool-season seeding mixes to provide rapid initial erosion protection?
- Bermudagrass
- Annual ryegrass (Lolium multiflorum) (Correct answer)
- Switchgrass
- Bahiagrass
Correct answer: Annual ryegrass (Lolium multiflorum)
Annual ryegrass germinates rapidly (5-7 days) and provides quick ground cover while slower-establishing permanent species develop.
Question 7: A CPESC practitioner observes that a newly seeded slope has bare patches where runoff channels have formed. Which corrective action should be taken FIRST?
- Reseed immediately without addressing the channels
- Install temporary sediment barriers and regrade channels before reseeding (Correct answer)
- Apply additional fertilizer to encourage lateral spread
- Increase irrigation frequency
Correct answer: Install temporary sediment barriers and regrade channels before reseeding
Rilling and channeling must be graded out and stabilized with temporary controls before reseeding to prevent recurring erosion at the same locations.
CPESC Vegetative Stabilization 2
What is the minimum recommended seeding rate for tall fescue (Festuca arundinacea) when used as a permanent erosion control cover on disturbed slopes?