A study was conducted with the objective to determine the humus content of surface and depth rhizosphere of 10 different plant species and concluded that the plant litters of Delonix regia are comparatively of best quality to be used as substrate by soil microbes and enzymes for decomposing and stabilizing it into humus. In support of the work, the change in activity of different carbon cycling enzyme has also determined in incubated soil alone and in soil with plant litter(50:1) for an interval of 20, 40 and 60 days respectively. 20 days incubation was found to be more effective in both except that of tyrosinase enzyme. The enzymes taken under consideration are dehydrogenase, phenol oxidase, peroxidase, laccase, cellulose and tyrosinase. Plant litters in soil have more enzymatic activity as compared to soil alone for all incubation periods.
