**4. Principles of nano-fertilizers preparation**

*The dissolution kinetics of nano-particle* by The Scientist Noyes-Whitney. The dissolution rate of nano-particles of the nano-fertilizers is directly proportional to their surface area because a relatively larger interface for dissolution is available, which promotes the dissolution of dissolved ions away from the particle.

According to *the Ostwald-Freundlich principle.*

The relative solubility of a spherical particle of the same material increases as the particle size decreases in the solid-liquid system—the solubility of the particle increases when the equivalent spherical diameter is <0.1 um.
