As a knowledgeable "lurker" I couldn't resist adding another comment or two:
First, I didn't notice Bill Duesing saying that he thought any production methods other than organic should be eliminated tomorrow, he was just talking about his own experiences. This seems to elicit a common defensive reaction whenever organic methods are described as beneficial or even possible--"but not everyone can do it that way." Sure, but lets keep trying to do better.
Second, the Irish potato famine occurred before the concept of "organic" arose, and can't legitimately be accused of being consistent with organic management. Most notably, it was a failure that could be more accurately ascribed to monoculture and genetic uniformity, as Mooney & Fowler so brilliantly explain in Shattering. This system is not organic, and a modern grower who did not rotate potato crops, for example, would not qualify as an organic grower.
That's it for now--thanks for so many thoughtful postings.
Grace Gershuny
USDA, National Organic Program