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氮是植物营养中的一个必需元素,氮占大气的70％,但它不易被植物所利用。微生物能使这种非有效氮转变为植物的有效氮。这种媒介是细菌通过与豆科植物共生及非共生过程来实现。自生固氮菌(Azotobacterspp.)和贝氏固氮菌(Beijerinckia spp.)是异养的非共生固氮菌的两个主要类群,后者是热带土壤中所特有的。贝氏固氮菌与自生周氮菌相似,但它们在抗酸性和钙的需求量及其它某些性状方面有所不同。这类细菌即使在最适合的土壤条件下,存在的数量也有
Nitrogen is an essential element of plant nutrition, nitrogen accounts for 70% of the atmosphere, but it is not easily used by plants. The microorganisms can convert this non-available nitrogen into the plant’s available nitrogen. This medium is achieved through the symbiotic and non-symbiotic process of bacteria with legumes. Azotobacterspp. And Beijerinckia spp. Are two major groups of heterotrophic non-symbiotic azotobacteria, which are endemic to tropical soils. Azotobacter vinelandii is similar to autotrophic nitrogen bacteria but they differ in their resistance to acid and calcium requirements and some other traits. This type of bacteria is present in even the most suitable soil conditions