Fertilizer classification — Calcium ammonium nitrate (CAN) is best classified as which type of fertilizer product?

Introduction:
Calcium ammonium nitrate (CAN) is a widely used nitrogenous fertilizer. Correct classification helps agronomists communicate nutrient planning and assess storage/handling requirements.

Given Data / Assumptions:

• CAN contains ammonium nitrate blended with powdered limestone or dolomite.
• Primary plant nutrients are N, P, K. Secondary include Ca, Mg, S.
• Calcium content improves handling and reduces explosion risk versus pure ammonium nitrate.

Concept / Approach:
A straight fertilizer supplies only one primary nutrient. CAN provides nitrogen as its primary nutrient; calcium (and sometimes magnesium) are secondary nutrients and do not change the classification to “mixed,” which requires at least two of N, P, K. CAN is therefore a straight nitrogenous fertilizer.

Step-by-Step Solution:
Identify primary nutrient(s) supplied: nitrogen only.Recognize calcium is a secondary nutrient; presence does not make it “mixed.”Classify CAN accordingly as a straight fertilizer.

Verification / Alternative check:
Extension bulletins and fertilizer regulations list CAN under straight nitrogen fertilizers, distinct from NPK complexes or blends.

Why Other Options Are Wrong:

• Mixed fertilizer requires at least two of N, P, K.
• Complex fertilizer refers to chemically combined multi-nutrient salts (e.g., diammonium phosphate), not CAN.
• “Not a fertilizer” is false; CAN is a common agricultural N source.
• It is not a biofertilizer.

Common Pitfalls:
Confusing presence of secondary nutrients with “mixed”; conflating CAN with ammonium nitrate hazards.

Final Answer:
A straight fertilizer (supplies a single primary nutrient, nitrogen)