Fertilizer additives — Why are conditioners such as finely divided peat added to granular fertilizers during manufacture and storage?

Introduction:
Granular fertilizers can absorb moisture and undergo physical changes during handling and storage, leading to caking, hardening, and poor flowability. Conditioners are minor additives used to maintain product integrity and ensure consistent field application.

Given Data / Assumptions:

• Finely divided peat is cited as a representative conditioner (others include clays, talc, or lignite).
• Focus is on physical handling properties, not nutrient chemistry.
• Granular products are stored in bags or silos under varying humidity.

Concept / Approach:

Conditioners act as moisture scavengers, anti-caking agents, or surface coatings to reduce inter-granular bridges formed by dissolved–recrystallized salts. By interrupting crystal growth and minimizing liquid bridges, they prevent hard agglomerates, keeping fertilizers free-flowing. They do not materially increase nutrient content or significantly alter solubility or pH.

Step-by-Step Solution:

Verification / Alternative check:

Fertilizer quality standards specify anti-caking additives and coating oils to maintain flow; industry practice confirms their effectiveness.

Why Other Options Are Wrong:

A: Burning relates to foliar application rates, not storage. C: Bulking without purpose adds cost. D: Solubility is governed by salt chemistry, not conditioners. E: Peat does not reliably raise pH.

Common Pitfalls:

Confusing anti-caking conditioners with nutrient coatings (e.g., sulfur or polymer for controlled release).

Final Answer:

to avoid caking and hardening