Composting manure might concentrate metals, and other issues, which are difficult to think about when the processes are not known to the buyer: http://www.slate.com/articles/health_and_science/green_room/...

My grandpa who had an orchard was not into organic farming at all, but also he already used wasps to get rid of certain insects. I think it's important to know what happens down there on the field and to me "organic" comes across at times as a marketing trick, but's that maybe me. :-)