Organic Matter Mineralization and Decomposition

Abstract

Organic matter mineralization is the transformation of organic C and nutrients into inorganic forms or into smaller, simpler organic compounds if mineralization is not complete. Organic matter mineralization is of central importance in many ecosystem functions. Methods to measure organic matter decomposition and mineralization are discussed in this chapter. The litterbag technique is the most widely used method for determining short-term decomposition rates and nutrient mineralization–immobilization dynamics of fine fresh litter (leaves, plant reproductive parts, fine roots, and small-diameter wood). Soil heterotrophic respiration is measured as the production of CO2 and CH4. The alkali absorption method for CO2 production and the gas chromatography method for CO2 and CH4 production are described. A method to measure the photodegradation of dissolved organic matter to CO2 is also described.