Wednesday, November 7, 2007
328-13
Decomposition Dynamics of Crop and Plant Biomass in Relation to Physico-Chemical Quality, Relative Placement, and Soil Microclimate.
Moniruzzaman Khan Eusufzai and Katsumi Fujii. JAPAN,Iwate Univ., Iwate University Faculty of Agriculture, 3-18-8 Ueda Morioka, Iwate, 020-8550, JAPAN
Understanding the decomposition dynamics of crop and plant biomass is essential for soil quality improvement and to find an appropriate strategy for carbon sequestration. We conducted fine mesh litterbag experiments to quantify the decomposition of rice straw, wood bark and sawdust in respect to C/N ratio, above and below ground placement of biomass and soil microclimatic effects. We tested the hypothesis that, high C/N ratio, above ground placement, low soil moisture & temperature inhibits the microbial activity and thus decomposition rate. On the contrary, low C/N ratio, below ground, high soil moisture and temperature accelerates the decomposition process. Initially, the decomposition rate was high irrespective of C and N content in such a way that rice straw>wood bark>sawdust. However at the end of study period, decomposition almost ceased and remained constant. Single pool exponential decay model were used to simulate the decomposition rate observed with conventional mass change.