Rice straw was converted into compost having high content of humic substances, following a two-step composting process. The first step involved degradation of rice straw by selected lignin degrading fungi, Polyporus versicolor, Phanerochaete chrysosporium and Ganoderma eucidum. The second step involved humification by general composting process. The extent of degradation was measured in terms of total loss in weight, loss in organic carbon, lignin and cellulose of the decomposing material. The extent of humification was measured in terms of increase of humic and fulvic acids and CEC of the final compost. Greater loss in weight and greater increase in humic substances and CEC of the composts inoculated with lignin degrading fungi showed the effectiveness of fungi in accelerating decomposition as well as humification of rice straw. Efficiency of the three fungi was in the order: P. chrysosporium > P. versicolor > G. eucidum.
Rice straw, lignin degrading fungi, two-step composting process, humic acid, fulvic acid
