CCA - Certified Crop Advisor Fertilizer Sources and Application Questions and Answers

Question 1

A producer plans to topdress urea (46-0-0) on an established cool-season grass pasture.
Warm, breezy conditions are forecasted with no chance of rain for several days.
Which of the following describes the primary nitrogen loss pathway of concern and the best management practice to mitigate it?

Accepted Answer

Volatilization of ammonia; use a urease inhibitor or time the application just before a significant rainfall event.

Answer

Denitrification of nitrate; incorporate the fertilizer immediately with tillage.

Answer

Leaching of nitrate; apply a nitrification inhibitor with the urea.

Answer

Immobilization by soil microbes; switch to a different nitrogen source like ammonium nitrate.

Question 2

Which of the following statements accurately compares the initial soil reaction of monoammonium phosphate (MAP, 11-52-0) and diammonium phosphate (DAP, 18-46-0) when applied as a granular fertilizer?

Accepted Answer

MAP creates an acidic reaction in the soil immediately around the granule, while DAP creates an alkaline reaction.

Answer

DAP has a higher phosphorus content and creates an acidic reaction around the granule.

Answer

Both MAP and DAP have the same neutral effect on soil pH around the granule.

Answer

DAP is less water-soluble than MAP, leading to slower initial phosphorus availability.

Question 3

A grower is planting corn into a cool, high-residue, no-till field. A recent soil test indicates low phosphorus (P) levels. Which fertilizer placement method would be most efficient for providing phosphorus to the young corn plant?

Accepted Answer

Banding the phosphorus fertilizer 2 inches to the side and 2 inches below the seed at planting.

Answer

Topdress application of granular phosphorus fertilizer over the growing crop at the V3 stage.

Answer

Broadcast application of phosphorus fertilizer in the fall prior to planting.

Answer

Foliar application of a low-salt phosphorus product at the V5 growth stage.

Question 4

A grower is selecting a fertilizer for an in-furrow (pop-up) application at planting. Which of the following common fertilizer sources has the highest salt index, posing the greatest risk of seedling injury if applied at excessive rates?

Accepted Answer

Potassium Chloride (KCl)

Answer

Monoammonium Phosphate (MAP)

Answer

Triple Superphosphate (TSP)

Answer

Urea

Question 5

A farmer incorporates a large amount of mature cereal rye cover crop residue, which has a high carbon-to-nitrogen (C:N) ratio, into the soil shortly before planting corn. What is the most likely immediate effect on nitrogen availability for the corn crop?

Accepted Answer

A temporary decrease in available soil nitrogen due to microbial immobilization.

Answer

A rapid increase in available nitrogen due to fast mineralization of the residue.

Answer

No significant change in nitrogen availability, as the corn crop cannot use organic N.

Answer

An immediate increase in atmospheric nitrogen fixation by free-living bacteria.

Question 6

What is the primary agronomic advantage of using a chelated form of a micronutrient, such as zinc EDTA, compared to an inorganic salt form, like zinc sulfate, particularly in high pH or high phosphorus soils?

Accepted Answer

The chelate protects the nutrient ion from being tied up by adverse soil reactions, keeping it available for plant uptake.

Answer

Chelated forms are significantly less expensive per pound of actual nutrient.

Answer

The chelate lowers the soil pH in the application zone, increasing general nutrient availability.

Answer

Chelated forms provide a much slower, season-long release of the nutrient.