CGM Horticulture Practices & Plant Health 3 — Questions and Answers
Question 1: What is the primary purpose of performing a soil percolation test before installing an irrigation system?
- To measure soil pH and nutrient levels
- To determine how quickly the soil drains water (Correct answer)
- To identify thatch accumulation depth
- To assess compaction using a penetrometer
Correct answer: To determine how quickly the soil drains water
A percolation test measures the rate at which water moves through the soil profile, informing irrigation scheduling to prevent over- or under-watering.
Question 2: Deadheading flowering annuals throughout the growing season is primarily done to:
- Increase the size of individual flowers
- Promote continued blooming by preventing seed set (Correct answer)
- Reduce fertilizer requirements
- Harden the plant tissue against frost
Correct answer: Promote continued blooming by preventing seed set
Removing spent flowers before seeds mature prevents the plant from diverting energy into seed production, encouraging continuous flower production.
Question 3: Which integrated pest management (IPM) strategy should be applied first before any other control measures?
- Apply a broad-spectrum pesticide to eliminate all pests
- Identify the pest and establish an action threshold (Correct answer)
- Release beneficial insects immediately
- Remove all affected plant material
Correct answer: Identify the pest and establish an action threshold
IPM requires accurate pest identification and establishing an economic or aesthetic action threshold before selecting any control tactic.
Question 4: A grounds manager observes wilting in a newly seeded lawn despite adequate rainfall. The most likely cause is:
- Insufficient phosphorus in the soil
- Hydrophobic soil conditions repelling water (Correct answer)
- Excessive potassium levels
- Iron deficiency in the seedlings
Correct answer: Hydrophobic soil conditions repelling water
Hydrophobic (water-repellent) soil, often caused by dry organic matter or certain fungi, can prevent water infiltration even when rainfall amounts appear sufficient.
Question 5: The ANSI A300 pruning standards recommend leaving the branch collar intact when removing a limb primarily because:
- It improves the aesthetic appearance of the cut
- It contains protective tissue that seals the wound (Correct answer)
- It reduces sap flow to speed drying
- It prevents frost damage at the cut site
Correct answer: It contains protective tissue that seals the wound
The branch collar contains chemically and structurally distinct tissue that compartmentalizes decay and seals over the wound; removing it exposes the trunk to decay.
Question 6: When scheduling pesticide applications, grounds managers must consider the pesticide label's re-entry interval (REI) because:
- It indicates when the product must be reapplied for effectiveness
- It specifies the minimum time workers must stay out of treated areas (Correct answer)
- It describes the period before the product becomes environmentally inactive
- It defines storage conditions required after application
Correct answer: It specifies the minimum time workers must stay out of treated areas
The REI is a legally required safety period during which workers cannot enter treated areas without personal protective equipment to avoid exposure to pesticide residues.
Question 7: Which soil amendment is most appropriate for improving drainage in a heavy clay soil used for landscape plantings?
- Peat moss added at 1-inch depth
- Coarse sand mixed at 25–50% by volume (Correct answer)
- Fine sand added at 10% by volume
- Additional clay to stabilize particle size
Correct answer: Coarse sand mixed at 25–50% by volume
Incorporating coarse sand at 25–50% by volume significantly alters clay soil structure and improves drainage, while smaller amounts or fine sand can worsen compaction.
CGM Horticulture Practices & Plant Health 3
What is the primary purpose of performing a soil percolation test before installing an irrigation system?