Have it in mind that the laboratory will not give you the condition you will get on the field although you can still get some results in the laboratory but in my own knowledge, I don't think you can effectively and efficiently determine rhizosphere competency of microorganisms in the laboratory. Growth chambers can be used in a controlled experiment but how do you account for the competition of the indigenous microorganisms on the field? How do you account for the interkingdom interactions such as protists, phages, environment interactions, etc? All these affect the competence of an introduced microorganism in the rhizosphere. T o sum it up, the best option is to introduce your microorganism to the natural environment and check the competency.

Thanks, Oluwaseyi Samuel Olanrewaju well explained. I totally agree with you.

Suppose salt tolerance potential of a microorganism and reported level of salt in the soil is 10 ppm, so keeping in mind the competition in the field, in vitro experiments should be done at 100 ppm or more. Moreover, microbial consortia can be studied instead of individual isolates. Please share your views.

Yes, the beneficial microbes that used as biofertilizers, before entering the field, their plant growth-promoting properties are examined in the laboratory and in-vitro condition. For example, in a study, we finally achieved the superior 4 isolates of 150 bacterial isolates in terms of low-soluble phosphate dissolution. In addition to the low phosphate solubility properties, they showed the other plant growth-promoting traits such as phytohormone auxin production, siderophore production, antifungal properties, etc.

Therefore, by observing the mentioned properties of selected bacteria, we used them as microbial fertilizers and applied them on the corn plant, and positive results were observed.