The reason may be related to the large-scale use of chemical fertilizers in the world, and it is also related to its relatively complex technology, high cost, low reliability and low return. For the former, although the application of chemical fertilizers in agricultural production has a large effect and a rapid effect, its long-term application will increase the negative impact on agriculture and the ecological environment. For the latter, the development of new large-scale nitrogen-fixing cyanobacteria production technology and new inoculation technology are gradually eliminating these defects.