Methods for determination of labile soil organic matter: An overview

Abstract

Methods for determination of labile soil organic matter: An overviewSoil organic matter (SOM) can be divided into three main pools: labile, stable and inert. Research over recent years has focused on the labile fraction (LF), as it is considered a quickly reactive indicator of soil productivity and health, and important as a supply of energy for soil micro-organisms. A wide spectrum of analytical methods has been used to determine and/or evaluate LF, based on physical, chemical and biochemical principles. The advantages and disadvantages of each technique are explored in this work, but none of the methods can determine LF sufficiently, either because a part of the LF is not involved or because further characterisation is missing. Although analytical methods are widely used to evaluate changes in soil management or organic carbon turnover, the practical question of the quantity and quality of SOM cannot be answered completely. It is also suggested that future research should focus on the interactions among SOM fractions and their better chemical and functional characterisation. It is possible to use a combination of the analytical methods reviewed here in order to accomplish this objective.