Analysis of Soil Microbial Flora Based on Carbon Source Utilization Pattern and Assessment of Pesticides Effects on Rice Paddy Soil Ecosystem.

通过培养水稻土样品的总微生物接种量，验证了biologg方法是一种独立于分离的微生物区系鉴定方法。在此基础上，以低投入量和常规投入量稻田为对照，对两个生长季土壤微生物种群、生物量、活性和区系的自然波动进行了监测，以评价农药对土壤生态系统的副作用。在室内试验中，采用生物学方法考察了两种农药对土壤微生物区系的影响。1) Biolog方法表征微生物区系的评价用稀释的土壤溶液接种Biolog GN板，定期测定每孔吸光度值。利用SPSS软件进行聚类分析，对Biolog板上阳性孔的模式进行分组。各参数的变异系数分别为：硝化活性（16-20%）、氨化活性（39-53%）、蛋白酶活性（31-62%）、铵氧化剂（88-174%）、微生物生物量氮（19-37%）、微生物生物量碳（15-30%）、ATP含量（28-44%）、好氧菌（39-46%）、革兰氏阴性菌（51-59%）、厌氧菌（42-61%）、真菌（33-52%）。两个稻田间的值无显著差异。稻田微生物区系划分为两大类群，分别属于淹水期和非淹水期，表明稻田微生物区系形成于氧化还原性土壤环境。这些结果表明，本研究中测量的微生物参数在自然压力和人类压力下波动。因此，这些结果可作为农药对稻田土壤微生物生态系统风险评价的参考。3)农药对土壤微生物区系的影响采用Biolog方法对土壤淹水和施用农药引起的不同微生物区系进行了检测。农药对水稻土微生物区系的影响可以通过与土壤氧化还原条件变化的影响进行比较来评价，土壤氧化还原条件对水稻土微生物区系的影响最为显著。少

The Biolog method was examined as an isolation-independent method to characterize microbial flora by incubating total microbial inoculum from paddy soil samples. Then, the natural fluctuation in the soil microbial population, biomass, activity and flora of two different rice paddies (low-chemical-input and conventional) were monitored during two growing seasons as reference in order to assess the side-effect of pesticides on soil ecosystem. Effect of two pesticides on soil microbial flora was also examined using the Biolog method in laboratory experiments.1) Evaluation of the Biolog method to characterize microbial floraThe Biolog GN plate was inoculated with diluted soil solutions and absorbance values at each well were measured periodically. Patterns of the positive wells in the Biolog plates could be grouped by the cluster analysis using the SPSS software.2) Natural variability in soil microbial population, biomass, activity and floraThe coefficient of variation for each parameter w … More as as follows : nitrification activity (16-20%), ammonification activity (39-53%), protease activity (31-62%), ammonium oxidizer (88-174%), microbial biomass nitrogen (19-37%), microbial biomass carbon (15-30%), ATP content (28-44%), aerobic bacteria (39-46%), Gram-negative bacteria (51-59%), anaerobic bacteria (42-61%), and fungi (33-52%). There was no significant difference in the values between the two paddies.Microbial flora in both paddies was separated into two major groups, which belonged to flooded and unflooded periods, indicating that the characteristic microbial flora was formed in the oxidative and reductive soil environments.These results indicate that the microbial parameters measured in this study fluctuate by natural stresses as well as anthropologic stresses. Therefore, these results should be used as reference when conduct risk assessment of pesticides to the microbial rice paddy soil ecosystem.3) Effect of pesticides on soil microbial floraDifferent microbial flora caused by soil flooding and application of pesticide was detected using the Biolog method. Effect of the pesticides on microbial flora could be assessed by comparing it with the effect of changes in the soil redox conditions, which have the most significant effect on microbial flora in paddy soils. Less