ABSTRACT
Soil organic matter (SOM) can be characterized in different ways, depending on the purposes. Total organic carbon (TOC) and carbon to nitrogen ratio (C:N) are commonly used to quantify and qualify SOM. Many different extraction and fractionation schemes have been developed in order to study the composition of SOM. However, the most commonly used extractant is a dilute alkali solution (NaOH), which was introduced by Russian scientists in the 18th century (Kononova, 1961). The dilute alkali solution remains the most effective and most widely used extractant for SOM.
