The Effect Of Microbial Fertilizer On The Nitrate Cummunication In Rape

With the improvement of people’s living standard, food safety is more and more important. Nitrate pollution in vegetables is a problem of the most common and most easily overlooked. It has become a hot topic how to reduce nitrate accumulation in plant. Many studies show that the content of nitrate is mainly affected by nitrogen. The measures to reduce nitrate include reducing nitrogen fertilizer,changing the structure of nitrogen fertilizer, adding nitrification inhibitor and so on. The study about Microbial fertilizer is relatively less and immature, and so far there is no consistent findings. In this thesis, it was studied the effect of several microbial fertilizer on rape nitrate content, nitrate reductase, soluble sugar content, soluble protein content, fresh weight per plant. It analyzed the effect of microbial on the nitrogen absorption and utilization in rape. In addition, this paper explored the effect of CO2on nitrogen accumulation from the perspective of carbon accumulation in order to look for a green, effective and applicabilitable measure to reduce nitrate accumulation and also to provide a theoretical basis for both the application and development of microbial fertilizer.The main conclusions are as follows:1. Soil moisture, nitrogen concentration, harvest time can all affect the rape nitrate content. The test determined the optimum moisture conditions17.5%-20%.The longer the harvest time away from fertilization time,the better it was. Rape nitrate content increased with the nitrogen concentration increasing, but no further increase to a certain degree.2. The rape yield and content of nitrate was highest when nitrate was offered as nitrogen. Adding Bacillus megaterium, Bacillus mucilaginosus Krassilnikov, Paenibacillus polymyxa and photosynthetic bacteria nitrate content decreased, expect for Bacillus mucilaginosus Krassilnikov foliar application was better, it was better root irrigation than foliar application.3. The yield and nitrate content were both lowest while ammonium nitrogen as nitrogen offer. Bacillus mucilaginosus Krassilnikov increased the nitrate content of rape, even resulted in nitrate pollution.4. Applying acid nitrogen for nitrogen fertilizer Bacillus megaterium, Bacillus Krassilnikov, Bacillus subtilis could effectively reduce the nitrate content in rape.5. The results of effective strain combination test showed that the composite bacterial reduce less nitrate than the single bacterial.6. Adding CO2effectively reduced rape nitrate content and increased the yield of rape. Adding CO2to the bacteria reduced more nitrate content.