[Characteristics of Microbial Nitrogen Degradation in Fluvo-aquic Soil of Hebei Plain]

Understanding the law of soil microbial degradation of nitrogen is of great practical significance for the remediation of soil nitrogen pollution. From fluvo-aquic soil of Hebei plain, 8 kinds of bacteria,including nitrification bacteria, ammonification bacteria, heterotrophic nitrification to aerobic denitrification bacteria were isolated and analyzed by 16S rDNA identification, and the most suitable strains were selected to prepare bacterial agents with optimized carrier materials. The effects of the screened strains of bacteria or antagonistic fungus to Chinese cabbage in the process of drip irrigation on nitrogen and PLFA (Phospholipid Fatty Acids) values in the soils were discussed. The results showed that by using diatomite as a carrier, the ammonia nitrogen degradation rate was 38% and the synthetic rate of nitrate was 205% with ammonibacteria, the synthetic rate of ammonia nitrogen was 1711% with ammonibacteria, the degradation rate of nitrate nitrogen was 367% with heterotrophic nitrification to aerobic denitrification bacteria. In drip irrigation experiment, total nitrogen and ammonia nitrogen in soil were better degraded and nitrification was stronger in the soil, meanwhile, PLFA in the soil increased and content of microbes reached the peak in shorter time, the soil biological environment was better after irrigation with screened bacteria.