Organic farming is far superior to conventional systems on so many levels. This is true with respect to building, maintaining and replenishing the health of the soil. And from the standpoint of soil health alone, organic agriculture is more sustainable, as you may guess, than conventional farming.
Rodale Institute has demonstrated that organic farming is better equipped to feed us now and well into the ever changing future, after 30 years of side-by-side research in their Farming Systems Trial (FST)®
For more information and some fast facts about organic farming vs. conventional- go to link