CFA Label Interpretation and Calculations 2 — Questions and Answers
Question 1: A fertilizer bag lists the guaranteed analysis as 10-5-8. What does the middle number (5) represent?
- Total nitrogen percentage
- Available phosphate (P2O5) percentage (Correct answer)
- Soluble potash (K2O) percentage
- Calcium percentage
Correct answer: Available phosphate (P2O5) percentage
The middle number in the N-P-K analysis always represents available phosphate expressed as P2O5.
Question 2: A fertilizer label states 'Apply at 4 lbs per 1,000 sq ft.' How many pounds are needed for a 15,000 sq ft lawn?
- 45 lbs
- 60 lbs (Correct answer)
- 75 lbs
- 80 lbs
Correct answer: 60 lbs
4 lbs × (15,000 ÷ 1,000) = 4 × 15 = 60 lbs.
Question 3: What does the term 'slow-release nitrogen' on a fertilizer label indicate?
- Nitrogen is in nitrate form only
- Nitrogen is converted by soil microbes or water over time (Correct answer)
- Nitrogen content is lower than fast-release products
- Nitrogen must be watered in within 24 hours
Correct answer: Nitrogen is converted by soil microbes or water over time
Slow-release nitrogen is formulated to break down gradually via microbial activity or hydrolysis, extending nutrient availability.
Question 4: A 50 lb bag of 20-0-10 fertilizer is applied to 5,000 sq ft. How many pounds of actual potash (K2O) are applied?
- 2 lbs
- 5 lbs (Correct answer)
- 10 lbs
- 50 lbs
Correct answer: 5 lbs
50 lbs × 10% K2O = 5 lbs of actual potash applied.
Question 5: Which section of a fertilizer label is legally required to list nutrient guarantees?
- Directions for use
- Guaranteed analysis (Correct answer)
- Precautionary statements
- Storage instructions
Correct answer: Guaranteed analysis
The 'Guaranteed Analysis' section is the legally mandated portion listing minimum nutrient percentages.
Question 6: A spreader is calibrated to deliver 3.5 lbs of product per 1,000 sq ft. What total product is needed for an 8,500 sq ft area?
- 24.5 lbs
- 28.0 lbs
- 29.75 lbs (Correct answer)
- 35.0 lbs
Correct answer: 29.75 lbs
3.5 lbs × (8,500 ÷ 1,000) = 3.5 × 8.5 = 29.75 lbs.
Question 7: A fertilizer label lists 'Derived from: urea, muriate of potash.' What does this statement indicate?
- The fertilizer is organic
- The sources of nutrients in the product (Correct answer)
- The manufacturing process used
- The solubility of the product in water
Correct answer: The sources of nutrients in the product
The 'Derived from' statement identifies the specific ingredient sources that provide the guaranteed nutrients.
CFA Label Interpretation and Calculations 2
A fertilizer bag lists the guaranteed analysis as 10-5-8.
What does the middle number (5) represent?