Barry Green, who runs the Tourist Radio network here in Western Australia, runs Boronia Farm using Permaculture principles. He has a point of view about organic farming worth hearing, and a down to earth way of explaining it:
When we apply soluble fertilizers the plant draws in water and takes on all the nutrients that are floating around in the water. Because the plant grows larger than before we think we are clever, but if people live on Coke and Big Macs they to grow to spectacular size but this does not mean that they are healthy, so too with plants. Plants fed on a soluble fertilizer diet are basically less healthy, and so attract pests and diseases that have evolved in nature to help weed out unhealthy specimens so that only the strongest survive. Having created unhealthy plants farmers are then locked into an expensive spraying program to protect the plants that no longer can protect themselves.
You can read Barry’s excellent article in full here, as well as refer to an excellent set of resources he has put together about organic farming: