Effects of Different Fertilizers on the Diversity of Rhizospheric N2-fixing Bacteria

• Main Authors: Hung-Yi Chu, 朱宏怡
• Other Authors: Chen-Chung Tan
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/37894521174555176838

碩士 === 國立中興大學 === 土壤環境科學系 === 90 === To maintain a proper soil microbial ecology is important to sustainable agriculture. In agricultural system, application of chemical and organic fertilizers may change the soil microbial community, including N2-fixing bacteria in rhizosphere. The experimental site was located at Kaohsiung district agricultural improvement station. An experiment dealing with organic and chemical fertilizations has been conducting for 12 years long. The purpose of this thesis was to investigate the effect of different fertilizers on the diversity of N2-fixing bacteria in the rhizosphere. Biolog MicroPlate identification System was applied to test the changing in diversity of N2-fixing bacteria in rhizosphere, and the ability of N2-fixation also to be measured by acetylene reduction method. The results obtained shoes that the nitrogen fixation ability in crop roots with chemical fertilizer has lower tendency than organic and intermediate fertilizers. Chemical nitrogen fertilizer might inhibit the nitrogen fixation ability of N2-fixing bacteria in rhizosphere. No matter what rotation system was, the bacteria species similarity between organic and intermediate fertilization was higher than that between chemical and organic fertilization, and between chemical and intermediate fertilization. It suggests that chemical fertilization for a considerable long time could change the community of N2-fixing bacteria in rhizosphere. The principal component analysis shows that crop species affect the structure of N2-fixing bacteria community in the rhizosphere much more than fertilization.