In general, a cyanobacteria with bi

In general, a cyanobacteria with biofertilizer potential is selected to evaluate the growth and nitrogen degrading enzyme activity of microalgae in the laboratory, and to investigate the effect of the next microalgae on germination and yield increase of crops. Experiments should be carried out and cultivated at some sites. Investigate growth. However, the problems with laboratory screening are as follows: 1) In the laboratory, growth assessment of a single bird species is commonly performed, and in practical applications, mixed bird paper, often used; 2 ) Laboratory measurements of nitrogen-fixing enzyme activity are generally performed under nitrogen deficiency or nitrogen limitation, and the soil at the time of actual application is not under nitrogen deficiency, but during the life cycle of nitrogen-fixing cyanobacteria. The activity of the nitrogenolytic enzyme is changed. The index has only a reference value. 3) The mechanism for increasing the yield of cyanobacteria in crops is not limited to the increase of soil available nitrogen content by nitrogen fixation. Further, the soil microbial community is very rich, and even after inoculation of a large amount of nitrogen-fixing cyanobacteria, the cyanobacteria after the dynamic adjustment of the soil microbial community is still in a low abundance ratio. Since there may be reciprocal inhibition between the interactions between different nitrogen-fixing cyanobacteria and between cyanobacteria and soil microorganisms, there is a need to efficiently screen combinations of different nitrogen-fixing cyanobacteria.