CFA Interpreting Fertilizer Labels Questions and Answers

Question 1

An applicator needs to apply 1.5 lbs of actual nitrogen (N) per 1,000 sq ft.
They are using a fertilizer with a guaranteed analysis of 25-5-10.
How many pounds of this fertilizer product must be applied per 1,000 sq ft?

Accepted Answer

6.0 lbs

Answer

4.5 lbs

Answer

5.0 lbs

Answer

7.5 lbs

Question 2

A fertilizer label for a 50 lb bag of 10-20-20 also lists 'Potential Acidity: 400 lbs Calcium Carbonate Equivalent per ton'. What does this statement signify?

Accepted Answer

The fertilizer will lower the soil pH over time, and its acidifying effect is equivalent to that produced by 400 lbs of limestone per ton of fertilizer applied.

Answer

Applying one ton of this fertilizer has the same effect as adding 400 lbs of calcium carbonate, raising the soil pH.

Answer

The product contains 400 pounds of calcium carbonate per ton to buffer the soil against pH changes.

Answer

For every ton of fertilizer applied, 400 lbs of acidic compounds are released into the soil.

Question 3

A turf manager is applying fertilizer near newly germinated seeds and wants to minimize the risk of 'fertilizer burn'. Which of the following characteristics listed on a fertilizer label is the most direct indicator of this risk?

Accepted Answer

Salt Index

Answer

Percentage of water-insoluble nitrogen

Answer

Guaranteed analysis (N-P-K ratio)

Answer

Micronutrient content

Question 4

A fertilizer label displays a guaranteed analysis of 12-8-10. It also specifies that 3% of the total nitrogen is from ammoniacal nitrogen and 9% is from nitrate nitrogen. Which of the following statements is most accurate regarding this nitrogen composition?

Accepted Answer

The majority of the nitrogen is immediately available for plant uptake but is also more susceptible to leaching.

Answer

All the nitrogen is in a slow-release form.

Answer

The fertilizer has a strong acidifying effect due to the high ammoniacal nitrogen content.

Answer

The nitrogen will become available gradually over a period of 3 to 9 months.

Question 5

The guaranteed analysis on a fertilizer bag reads 15-0-30 and also guarantees 2% Magnesium (Mg) and 5% Sulfur (S). How many pounds of actual potash (K2O) and sulfur (S) are in a 50 lb bag of this product?

Accepted Answer

15 lbs of K2O and 2.5 lbs of S

Answer

30 lbs of K2O and 5 lbs of S

Answer

7.5 lbs of K2O and 1 lb of S

Answer

30 lbs of K2O and 2.5 lbs of S

Question 6

The second number in the N-P-K guaranteed analysis on a fertilizer label legally represents the percentage by weight of which compound?

Accepted Answer

Available Phosphate (P2O5)

Answer

Elemental Phosphorus (P)

Answer

Phosphoric Acid (H3PO4)

Answer

Water-Soluble Phosphorus (P)

An applicator needs to apply 1.5 lbs of actual nitrogen (N) per 1,000 sq ft.They are using a fertilizer with a guaranteed analysis of 25-5-10.How many pounds of this fertilizer product must be applied per 1,000 sq ft?

An applicator needs to apply 1.5 lbs of actual nitrogen (N) per 1,000 sq ft.
They are using a fertilizer with a guaranteed analysis of 25-5-10.
How many pounds of this fertilizer product must be applied per 1,000 sq ft?