Physical and Chemical Properties of Fertilizers and Methods for their Determination

Abstract

The physical form in which a fertilizer is produced is of considerable importance, both agronomically and in regard to satisfactory handling, transport, storage, and finally application to the field. Most of the problems encountered with fertilizers probably are those resulting from deficiencies in physical properties; frequent problems include caking, dustiness, poor flowability, segregation, and excessive hygroscopicity. Customer acceptance or preference for a particular fertilizer over another of equal plant-food content almost always is based on physical properties of the product. Good physical condition, which is relatively easy for the customer to evaluate by simple observation, ensures him of easier, faster, more uniform, and less expensive application to the field. Also, in the various handling, transport, and storage steps that usually are involved between production and final use of fertilizers, it is essential that physical properties be such that the material remains free flowing (noncaking), that it be relatively nondusty, and that it withstand a reasonable amount of exposure to normal atmospheric humidity. Many production techniques, including various physical “conditioning” treatments, have been developed especially to provide favorable physical properties.