A SIMPLE WET CHEMICAL-EXTRACTION PROCEDURE TO CHARACTERIZE SOIL ORGANIC-MATTER (SOM) .1. APPLICATION AND RECOVERY RATE

The knowledge of soil organic matter (SOM) composition is important for research in soil science. This is why two classical wet chemical extraction procedures were tested and combined to characterize SOM. Twenty-five samples from typical forest and arable soils in Schleswig-Holstein, Northwest Germany, were investigated in the laboratory. Lipids were extracted using a pre-step method. Several polysaccharide fractions were extracted sucessively with inorganic acids in a litter compound analysis (LCA). Proteins and lignins were determined in the bulk soil sample. In a humic compound analysis (HCA), fulvic and humic acids were extracted in the classical way with NaOH, and the non-humic substances were removed with the aid of the ''Sulfacetolysis'' from the residues (= usually ''humins''). The combination of these two wet chemical extraction proce dures (LCA and HCA) permitted quantitative estimations of the SOM composition in several soil horizons. The LCA method produced a better recovery rate (104%+/-4%) than the HCA methode (95%+/-15%). The litter compound/humic compound ratio of both analyses, and the combination of both correlated with visible humification grades in a significant way (r = -0.733 to -0.742***). LCA may be sufficient for solving special pedogenetic problems, because of its high recovery rate and the strong correlation between LCA and HCA.