| Abstract: | Quantitative determination of reduced substances in subhydric soils The determination of reduced substances is possible by rapid oxidation with a diluted potassium dichromate/sulfuric acid solution at room temperature, and subsequent titration with FeSO4 solution. These values (meq/100 ml of fresh sample) show a nonlinear, negative correlation with redox potential, and increase with increasing content of organic material. Sulfides, expressed as FeS, amount to appr. 50 % of the reduction equivalents. Subhydric soils rich in nutrients show an increasing amount of reduced substances with increasing depth, whereas oligotrophic and mesotrophic soils give no distinct depth function. |
