【摘要】 生物固氮不仅固氮量大，而且还可提高土壤肥力，改善土壤条件，不污染环境；更为重要的是它有取之不尽，用之不竭的廉价氮源，成本低，利用率高，因此，生物固氮是今后肥料发展的主要方向之一。更多还原

【Abstract】 Biological nitrogen fixation not only has large nitrogen-fixing capabilities, can raise soil fertility, but also can improve the soil and is harmless to environment. It is the most important that it has endless cheap source of nitrogen, it has low cost and high efficiency. So biological nitrogen fixation has become one of the main directions for today’s fertilizer development in the world.更多还原