I think I have come to the point where I no longer believe a meaningful
comparison could be made. Sustainable agriculture has been defined in
so many ways, by some many esteemed scientists and groups representing
scientists, that it has become virtually meaningless.
Just think about trying to find an agricultural scientist that is doing
research on "unsustainable" agriculture, and you get the picture.
You might contact Nic Lampkin at U. of Wales, (Aberystwyth) as a
excellent local source on organic agr. By the way, at least you can
find reasonably coherent sets of national and international standards
that define what types of farming practices can be certified as
"organic".