Microbial biomass carbon of each microcosm was measured by using fumigation-extraction method. Fumigated and non-fumigated soil (reference sample) samples were extracted with 40 mL of K2SO4 (0.5 mol • L-1) solution. Then, organic carbon of 1 mL extract was analyzed by using the carbon analyzer. Soil DNA was extracted from all soil samples by
using DNA kit D-5625-01 of OMEGA according to