i've spent a few years in the Bio-Dynamic world, and whilst my role is not gardening, i take part in alot of that and talk in detail with BD farmers, gardeners etc.. besides this i work (as an open-minded and kinda prospected outsider) within "Anthroposophy", the spiritual movement that underpins/created BD.

Whilst BD was developed as a movement in the 1920's iirc by the self-proclaimed seer Rudolph Steiner and some others (i CBA to look it up on wiki..), a lot of it's practices are simply good old fashioned traditional common sense, driven by care and not greed etc. It does contain some quite unconventional practices that are basicly a form of magic, but a focus on composting (albeit with semi-mystical preparations), soil care, and gaining an understanding the rhythms of the farm, the farmer and of nature are the key i guess.

The produce tho (and i never tried BD MJ btw..) is second to none taste wise, is supposedly infused with cosmic life forces (according to Mr Steiner), and is about as good/pure/green/whatever food can get. BD farms will often let you grow there yourself!

BD farms have a quite different nature to most other farms too, a focus on natural and (perceived) artistic harmony and their often communal and healing purposes for example.

kinda lost track there lol, but it's a start for you... much wierdness is contained within, especially when you into anthroposophy and Steiner himself - i find it fascinating as i'm fairly deep inside the Anthroposophical community and much of it is wonderful, but some of it is questionable, some of it daft, and some of it is just the result of 19th century religious romantics gone mad imo, but that's another story

bottom line tho, you get tastier food, a harmonious, resource-waste balanced farm, a more beautiful environment, and a happier farm and farmer... with no damage to the earth - in fact it is easily argued that BD enriches the earth.

oh yeah, and one last thing - the Shire analogy is spot on