Definition check:\n“Nitrolime” refers to which material used in agriculture and industry?

Introduction / Context:
Nomenclature in fertilisers and agrochemicals can be confusing. The term “nitrolime” has a long history and specifically refers to calcium cyanamide, not nitrate blends. It is valued for multiple roles: as a nitrogenous fertiliser, soil conditioner, and selective weed suppressant in certain crops when properly applied.

Given Data / Assumptions:

• Trade/legacy names may differ regionally, but “nitrolime” is widely equated with CaCN2.
• Other calcium-containing fertilisers include Ca(NO3)2 and CAN (ammonium nitrate + limestone), which are distinct.
• Application practices for calcium cyanamide require moisture and time to hydrolyse to plant-available forms.

Concept / Approach:
Calcium cyanamide is produced by reacting nitrogen with calcium carbide (Frank–Caro process). In soil, it hydrolyses to release plant-available nitrogen and can raise pH locally, also exhibiting herbicidal effects in specific contexts (e.g., onion fields). Therefore, among listed options, only calcium cyanamide correctly matches the definition of “nitrolime.”

Step-by-Step Solution:

Verification / Alternative check:
Agronomic references and historical fertiliser literature consistently list “nitrolime” as calcium cyanamide, with guidance on timing and soil conditions for safe, effective use.

Why Other Options Are Wrong:

• Calcium nitrate and CAN are nitrate-based fertilisers; they do not equal nitrolime.
• “Mixture of nitric acid and lime” and “ammonium nitrate + calcium nitrate” are not standard identities for nitrolime.

Common Pitfalls:
Assuming any calcium-containing nitrogen fertiliser is “nitrolime”; ignoring the unique cyanamide chemistry.

Final Answer:
Calcium cyanamide (CaCN2)