Abstract: By the methods of heating accumulation, nitrate-reduction gas production, and quantitative analysis of denitrification, a bacillus strain with highefficient denitrifying capability named as TGR30 was isolated from the sediment of Wuliangsuhai Lake. The isolate was identified as Bacillus megaterium, based on its morphological feature, biochemical characteristics, and 16S rDNA sequence analysis. Single factor experiment was conducted to investigate the influences of medium carbon, C/N, salinity, pH, and dissolved oxygen on the denitrifying characteristics of the strain. When the medium salinity was 6% or the pH value was 12, the strain still had high nitrogen removal capability, and the optimal conditions for the nitrogen removal were the medium C/N ratio 14, pH value 8.0, and dissolved oxygen concentration 4 mg·L^-1 when soluble starch was used as the sole carbon source.

Key words: greenhouse, soil moisture, soil temperature, ratio of soil water to heat.