Sterilized soil of course in order to avoid the positive or negative interaction of soil micro-flora. But if you are asking about whether sandy, silty or podzol soil are suitable or not for field trial after in vitro and in vivo test (pot experiment), I guess that sandy soil are more suitable during spring or even summer time. They have less organic matter content, low bulk density and suitable for vegetables growing Thus, you will have more response of your tested PGPR under those conditions in comparison with heavy soil.

Even in sandy soil, you might add some organic matter (sheep or cow manure 15T/ha) to allow your PGPR to be maintained at rhizosphera level as long as your experiment is conducted.

Good luck

Thanking you Dr. Azim, in-vitro is oK !!

But we want under field condition for long term experiment with PGPR,

Thanks for your valuable suggestions ~~ 

You welcome Dr. Vijay, as I said sandy soil is more suitable for this purpose, just work out the soil very well at 30cm depth and keep uncropped buffer zone (50cm at least) between plots to avoid lateral contamination (diffusion). Keep the soil wet to maintain your inoculum alive (sandy soil is susceptible to water infiltration -loss- more than heavy one). You can use drip irrigation to keep the soil wet also.

Hello, Dr. Vijay, Sandy soils are good choice for the planning of experiments. Silty soils and clay soils have some problem but your microbes are efficient enough then you will try on these also.

In case of field trials you will not maintain the sterility just like pot trials.

Before starting the trials you must analyse the soil that it falls under which class. There are two types of classification. so depending on the location of experiment you will confirm the class of the soil.

Best of luck.

See any soil can be used for PGPR experiments because microorganisms can grow in any environment. more the harsh soil role of bacteria is more to helps others to survive in the environment. only effectiveness of the PGPR can be differ based on the soil type........................like sandy soil, sandy loam soil, clay soil.............soil having more organic matter have the more potential to hold more microbial activity. according to me Sandy loam soil having 0.5 to 1.0 % soil organic carbon is the most suitable for subtropical region in India.

Mr, Hani Antaun I can't access your link http://www.bashanfoundation.org/publications.html