FREE CFA Label Interpretation and Calculations Questions and Answers

Question 1

An applicator has a 50-pound bag of granular fertilizer with a guaranteed analysis of 24-6-12. How many pounds of actual nitrogen (N), phosphate (P2O5), and potash (K2O) are in the bag?

Accepted Answer

12.0 lbs N, 3.0 lbs P2O5, 6.0 lbs K2O

Answer

The three numbers in the guaranteed analysis represent the percentage by weight of N, P2O5, and K2O. To find the pounds of each nutrient, multiply the total weight of the bag (50 lbs) by the percentage of each nutrient in decimal form. Nitrogen: 50 lbs * 0.24 = 12.0 lbs. Phosphate: 50 lbs * 0.06 = 3.0 lbs. Potash: 50 lbs * 0.12 = 6.0 lbs.

Question 2

A soil test recommends applying 90 lbs of phosphate (P2O5) per acre. The applicator will use diammonium phosphate (DAP), which has a fertilizer grade of 18-46-0. How many pounds of DAP are needed to apply to one acre to meet the recommendation?

Accepted Answer

195.7 lbs

Answer

The formula to determine the amount of fertilizer needed is: (Recommended rate of nutrient) / (Percentage of nutrient in fertilizer as a decimal). In this case, 90 lbs of P2O5 is needed, and DAP contains 46% P2O5. Calculation: 90 lbs / 0.46 = 195.65 lbs, which rounds to 195.7 lbs.

Question 3

An applicator is using a liquid fertilizer, 32-0-0 Urea Ammonium Nitrate (UAN), which has a density of 11.06 lbs per gallon. How many pounds of actual nitrogen are in a 30-gallon tank of this product?

Accepted Answer

105.8 lbs

Answer

First, calculate the total weight of the liquid fertilizer: 30 gallons * 11.06 lbs/gallon = 331.8 lbs. Next, calculate the pounds of actual nitrogen by multiplying the total weight by the percentage of nitrogen: 331.8 lbs * 0.32 = 106.176 lbs. The closest answer is 105.8 lbs.

Question 4

The guaranteed analysis on a fertilizer label (e.g., 10-20-10) legally represents the minimum percentage by weight of which three nutrients in order?

Accepted Answer

Total Nitrogen (N), Available Phosphate (P2O5), Soluble Potash (K2O)

Answer

By law, the three numbers in the guaranteed analysis on a fertilizer label represent the minimum percentage by weight of Total Nitrogen (N), Available Phosphate (P2O5), and Soluble Potash (K2O), in that specific order.

Question 5

A turf manager needs to apply 0.9 lbs of actual Nitrogen per 1,000 sq. ft. They are using a fertilizer with an analysis of 21-0-7. How many pounds of this fertilizer product must be applied to a 6,000 sq. ft. lawn area?

Accepted Answer

25.7 lbs

Answer

First, determine the amount of fertilizer product needed per 1,000 sq. ft. by dividing the target nitrogen rate by the nitrogen percentage: 0.9 lbs N / 0.21 = 4.286 lbs of product per 1,000 sq. ft. Second, scale this amount for the total area: 4.286 lbs/1,000 sq. ft. * 6 (since the area is 6,000 sq. ft.) = 25.716 lbs.

CFA Practice Test

CFA Practice Test

FREE CFA Label Interpretation and Calculations Questions and Answers