Relationships between methane emissions and soil microorganisms in a double-rice field in southern subtropical China

Methane is produced in anaerobic environments by obligate anaerobic microorganisms through the decomposition of organic matters. To investigate the regression relationships between methane emissions and soil microbes in a double-rice paddy under various field practices, a two-year study was conducted to investigate the seasonal variation of methane emissions and the total activities of soil microbes (TASM) as well as the populations of methanogens (PMET) using the static closed-chamber-GC (gas chromatography) and the most probable number methods. Seven management practices were included in this study to look at the average effect of field treatments on methane emissions and TASM as well as PMET, viz. CWS (conventional tillage + without straw residues + urea), NWS (no tillage + without straw residues + urea), SCU (conventional tillage + without straw residues + controlled-release urea), HN (high stubbles + no tillage + urea), HC (high stubbles + conventional tillage + urea), SN (straw cover + no tillage + ...