My industry (electricity) has an obvious interest in finding things that are underground (preferably before we stick a spade through them). Thirty years ago, I came across some serious research we'd done into whether dowsing worked. The conclusion from some pretty careful research was that dowsers were indeed good at finding things underground (water or metal) - but no better than someone else who was looking carefully for tell-tale signs. In other words, dowsers may just be people with acute (and possibly subconscious) observation skills and an understanding of how the ground and the things that grow on it are affected by what's underneath.
A bit like how much alternative medicine can be effective in the right circumstances despite having no direct physical basis.
