A Modified Method of Weight Loss on Ignition to Evaluate Soil Organic Matter Fractions

摘要

Chemical fractionation and quantification of Soil Organic Matter (SOM) pools involve laborious and time-consuming processes, which are also not very accurate. Therefore an attempt was made here to quantify the Fulvic Fraction (FF), Humic Fraction (HF) and soil litter which are known to be very important in nutrient availability in tropical ecosystems, by using weight Loss on Ignition (LOI) method. Cambisols in Sri Lanka was used to extract the humic substances and soil litter. The result indicated that the soil litter combusted at temperatures 170-190°C. Peak weight losses of the FF occurred between 200-250°C. The weight losses of the HF occurred at 500°C. The study clearly showed that soil litter combusted at temperatures 190°C. Therefore the LOI can be used as a quick and simple technique for the determination of soil litter, in particular and further the FF and HF, compared to conventional extraction methods. This will be very much useful in comparative studies where there are large numbers of samples to be analysed.