Very nice discussion Dr Wang and equally thoughtful responses from Prof Hani as usual . Its always heartening to read his thought provoking responses. My take on the whole issue is, is it necessary to sterilize the soil to study the responses of re-inoculation on microbial diversity . And , my second take is , a soil in its natural habitat will always maintain a definite microbial diversity while working with a particular crop , this is where rhizosphere is built up for microbial proliference , otherwise in the absence of crop , i do not think , it will make a viable exercise for objectives , we are aiming at . A soil as such will remain the soil only , no rhizosphere , unless crop component is added to facilitate metabolically active roots to interact with different soil components.