Well it's certainly an interesting question. Many permaculture practitioners don't see themselves as farmers, but as gardeners. Modern farming has moved towards monoculture on an industrial scale for what economists call "economies of scale". To support this method of farming though requires huge amounts of man-made inputs, in varying concentrations of Nitrogen, Phosphorous and Potassium... unless that is of course, you can find natural replacements for these much needed mineral inputs! (see forest gardening diagram below!)
So, production of food is of utmost importance, that's a gimme, but how are we going to provide for ourselves let alone our extended communities, counties, regions, countries or continents? If these fossil-fuel inputs are reducing, FACT, and monoculture farming is dependent upon these reducing inputs, FACT, why save farming?
"It’s probably too late to prepare for peak oil, but we can at least try to salvage food production." - George Monbiot, published in the Guardian 16th November 2009
http://www.monbiot.com/archives/2009/11/16/if-nothing-else-save-farming/
