CHT Soil Science & Fertilization 1 — Questions and Answers
Question 1: What soil pH range is generally considered optimal for most horticultural crops?
- 4.0–5.0
- 5.5–7.0 (Correct answer)
- 7.5–8.5
- 8.5–9.5
Correct answer: 5.5–7.0
A pH of 5.5–7.0 supports nutrient availability and microbial activity optimal for most horticultural plants.
Question 2: Which macronutrient is primarily responsible for promoting leafy, vegetative growth?
- Phosphorus (P)
- Potassium (K)
- Nitrogen (N) (Correct answer)
- Calcium (Ca)
Correct answer: Nitrogen (N)
Nitrogen (N) drives chlorophyll production and cell division, making it the key driver of vegetative, leafy growth.
Question 3: A soil test result shows a CEC of 25 meq/100g. What does this indicate?
- Very low nutrient-holding capacity
- High clay or organic matter content (Correct answer)
- Highly acidic soil
- Excessive drainage
Correct answer: High clay or organic matter content
A high CEC (cation exchange capacity) indicates abundant clay or organic matter, which holds more nutrient cations for plant uptake.
Question 4: Which fertilizer analysis number represents phosphorus content?
- First number
- Second number (Correct answer)
- Third number
- Fourth number
Correct answer: Second number
The N-P-K label lists nitrogen first, phosphorus (as P₂O₅) second, and potassium (as K₂O) third.
Question 5: Slow-release fertilizers are preferred in professional horticulture primarily because they:
- Are cheaper per application
- Reduce leaching and provide sustained nutrition (Correct answer)
- Work only in acidic soils
- Eliminate the need for irrigation
Correct answer: Reduce leaching and provide sustained nutrition
Slow-release fertilizers reduce nutrient leaching, lower burn risk, and supply steady nutrition over weeks or months.
Question 6: Which soil texture allows the best balance of drainage and water retention?
- Clay
- Sand
- Loam (Correct answer)
- Silt
Correct answer: Loam
Loam is a balanced mix of sand, silt, and clay that provides good drainage while retaining adequate moisture and nutrients.
CHT Soil Science & Fertilization 1
What soil pH range is generally considered optimal for most horticultural crops?