Not my area, but here's what is in RG that I hope would be helpful for you:

https://www.researchgate.net/search.Search.html?type=publication&query=determine%20a%20bacteria%20effect%20on%20plant

Best,

Debra

There is no test better than potted studies . But you need to be sure about the nature of properties of bacteria , you wish study their crop responses. Challenge inoculation studies can also be done but many times , the magnitude of crop response is not replicated in field...

Thanks for inspiring answers. I began to understand soil microbiology how is work. I think I need to work about Plant growth-promoting rhizobacteria and pot test. Thanks for answers.

1. By inoculation of seeds

2. By spraying the surface layer of the soil around the stem of the plant.

3. By inoculation of organic fartilizer (manure or compost) with Biocontrol agent (Trihoderma harzianum) or N2-fixing bacteria (Rhizobium, Bradyrhizobium etc)

There's some tests which will help u to find out that your isolated bacteria is beneficial for plant or not and it's also depends on from where you isolate bacteria

If you're bacteria is soulbalize phosphate and produce amonia and indol acetic acid or the ability of nitrogen fixaction than these are beneficial for plant growth

Most important is the fidelity of microbe identification and maintaining their purity under laboratory conditions over a period of time , since microbes gradually loose their vitality through subculturing under laboratory conditions.

Has anyone tried , taking rhizosphere soil from a healthy crop and inoculating the same healthy soil into unhealthy crops rhizosphere as a natural.microbial inoculant..???

Soil is abundant with millions of microbes but all of them were not helpful or sometimes they do not show their impact at right time for various reasons. Perhaps you can start screening your bacteria for various plant growth promoting properties like IAA, Gibberellic acid, cytokinins, phosphate solubilization, siderophore and HCN etc., For possible protocols and inoculation methods you can refer to Ali Skz papers.