dnaSRPS EN 18316:2025

Inorganic fertilizers - Determination of the total K2O content by gravimetry and inductively coupled plasma optical emission spectrometry (ICP-OES)

Scope

This document specifies two different methods (Method A and Method B) for the determination of the total potassium content (expressed as K2O) in inorganic fertilizers soluble in mineral acids. Method A specifies a gravimetric method. Method B specifies the method using inductively coupled plasma optical emission spectrometry (ICP-OES).
This document is applicable to fertilizing product blends, where the blend is a mix of at least two of the following components, fertilizers, liming materials, soil improvers, growing media, inhibitors and plant biostimulants, and where inorganic fertilizers are the highest % in the blend by mass or volume, or in the case of liquid form, by dry mass. If inorganic fertilizers are not the highest % in the blend, the European Standard for the highest % of the blend applies. In case a fertilizing product blend is composed of components in equal quantity, the user decides which standard to apply.
NOTE Variations in analytical methods for fertilizing product blends can lead to differing results as some components or matrix interactions can affect the outcome. Validation procedures have shown that developed standard methods are robust and reliable across diverse product compositions, but possible interferences and unexpected results when analysing fertilizing product blends are possible.

Related directives

NOTE: If the word "harmonized" (marked in green) is not found in the field with the name of the directive, it means that the European standard is not cited in the OJEU.