CHT Soil Science & Fertilization 2 — Questions and Answers
Question 1: What is the purpose of a soil percolation test?
- Measure pH
- Assess drainage rate (Correct answer)
- Identify soil pathogens
- Determine organic matter content
Correct answer: Assess drainage rate
A percolation test measures how quickly water drains through soil, helping determine suitability for plants and irrigation design.
Question 2: Micronutrient deficiencies often become apparent first in:
- Roots
- New growth (young leaves) (Correct answer)
- Older lower leaves
- Stems
Correct answer: New growth (young leaves)
Micronutrients like iron and manganese are immobile in plants, so deficiency symptoms appear first in new, young growth.
Question 3: Which amendment is most effective for raising soil pH?
- Sulfur
- Peat moss
- Agricultural lime (Correct answer)
- Ammonium sulfate
Correct answer: Agricultural lime
Agricultural lime (calcium carbonate) neutralizes soil acidity and raises pH when incorporated into the soil.
Question 4: Phosphorus application is best timed to:
- Be applied during heavy rain
- Be incorporated before planting (Correct answer)
- Be sprayed on foliage
- Be applied after harvest only
Correct answer: Be incorporated before planting
Phosphorus is relatively immobile in soil and should be incorporated before planting so roots can access it at the root zone.
Question 5: What does a green or blue-green soil crust indicate?
- High fertility
- Algae or cyanobacterial growth due to excess moisture (Correct answer)
- Proper drainage
- Calcium deficiency
Correct answer: Algae or cyanobacterial growth due to excess moisture
A green or blue-green surface crust typically indicates algae or cyanobacteria thriving in overly wet, compacted, or waterlogged conditions.
Question 6: Organic matter improves soil structure primarily by:
- Increasing soil density
- Binding soil particles into aggregates (Correct answer)
- Lowering soil pH significantly
- Eliminating all pests
Correct answer: Binding soil particles into aggregates
Organic matter acts as a binding agent, promoting aggregation of soil particles into crumbs that improve aeration, water infiltration, and root penetration.
CHT Soil Science & Fertilization 2
What is the purpose of a soil percolation test?