This method quantifies the active carbon pool in the soil. Active carbon (also known as Permanganate Oxidizable Carbon or POXC) is the portion of total organic matter that is readily available for soil microbial population. This method uses a deep purple colored potassium permanganate solution for the oxidation of active carbon. The solution loses some of its color upon oxidation of active carbon meaning the more the color declines, the more active carbon is found in the soil. A spectrophotometer set at 550 nm wavelength is used to determine this pool. Active carbon is reported as mg POXC/kg soil with a detection limit of 20 mg/kg.
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