shifts in microbial populations

[N. Kent Peters]

In our journal club, we have been discussing several papers that look at 
the genetic diversity of a soil population of bacteria.  Methods in 
these articles have varied but all have analysized site to site 
variation.  Does anyone know of studies that have looked at the same 
site through time.  Most importantly, if the time frame includes changes 
in vegetation of the soil or other factors.  For example, have there 
been any studies on changes observed in the soil population of bacteria 
during crop rotation?  

I would greatly appreciate any help in finding this literature if it 
exists.

Thanks,
N. Kent Peters
University of Tromsø
Tromsø, Norway
kent at ibg.uit.no