Exploring the influential factors of granular fertilizer caking: a comprehensive review

Abstract

The phenomenon of fertilizer caking has an impact on the commercial value of the final products. It can occur throughout the life cycle, including production, storage, transport and final agricultural application. Fertilizer caking leads to clumping and agglomeration and presents a significant challenge. This review comprehensively examines the mechanisms underlying granular fertilizer caking, focusing on the complex interactions at the granular level, particularly adhesive and phase contacts. These interactions, including solid–solid and solid–liquid contacts, are pivotal in the agglomeration process, with salt bridges from phase contacts being a critical factor in caking propensity. The review identifies numerous factors influencing fertilizer caking. Internal factors such as chemical composition, particle size, hardness, and moisture content, as well as external factors like weather fluctuations, pressure, storage duration, and the effectiveness of coating agents, profoundly affect caking behavior. By synthesizing existing literature, this work provides valuable insights into the multifaceted nature of granular fertilizer caking, elucidating the underlying mechanisms and factors involved. This review lays the groundwork for future research aimed at mitigating caking challenges in fertilizer production and storage.