This guy has indisputable credentials...

This is an amazing interview I can across by the late Norman Borlaug that basically makes the claim that organic agriculture is unsustainable because there isn't enough nitrogen available from organic sources. In other words there isn't enough poop (fertilizer) being produced to provide enough nitrogen in the soil if organic agriculture was the predominant agriculture modality.

Yes, it is from Reason magazine the mouthpiece of the Libertarian movement (yes, that does make it suspect) but on the other hand, this guy won the Nobel Peace prize in the 1970 for AGRICULTURE because the Nobel Committee declared that he did so much to bring about peace through developing farming methods to radically reduce starvation. He is said to be responsible for saving billions (yes, with a "b") lives through his work:

Here is the article: