Evaluation of Extractants to Quantify Dissolved Organic Carbon and Nitrogen in Dissimilar Soils

摘要

Dissolved organic matter (DOM) is the most mobile and dynamic non-living organic matter fraction which acts as source of readily available carbon (C) and nutrients for soil microbes (Marschner and Kalbitz 2003). The DOM is defined operationally as a continuum of organic molecules of different sizes and structures that pass through a filter of 0.45 um pore size (Thurman 1985). It is frequently used as indicator of soil organic matter (SOM) dynamics (Alvarez et al. 1998) because changes caused by environmental and management stresses are detected earlier in DOM than SOM as a whole. Since C represents the bulk of the organic matter (>50%), DOM is often quantified by measuring dissolved organic C (DOC) in soils. The retention and mobility of DOC in soils is controlled primarily by its binding to mineral surfaces (Kramer et al. 2012). Several studies have shown the effect of soil properties such as clay and OC content, surface charge, oxalate-extractable iron (Fe) and aluminium (Al), and pH on DOC recovery (Kogel-Knabner et al. 2008; Rashad et al. 2010).em:mavimsl6@pau.edu)