This is not one of Bush's more bizarre suggestions but it is one of those ideas that seem blindingly obvious when you hear about it.
A couple in Scotland have been experimenting for 20 years and since 1998 have been tending a barren hillside using their technique. They use volcanic rock dust from a local quarry instead of artificial fertiliser. Their theory is that applying the dust mimics the effect of a glacier passing over the ground and depositing minerals. These have of course been leeched out after the millenia since the last ice age.
What was once a windswept hillside just about able to produce rough grass has been transformed into a producive plot. The size of their crop is amazing with potaotoes big enough for one to feed a family, brussels sprouts the size of small apples, softball sized strawberries and "small" red cabbages the size of soccer balls.
Their charitable trust has now been given £95,000 ($175,000) to conduct proper experimental field trials. The technique seems to be very effective in very adverse conditions. If it proves succssful it could replace expensive artificial fertilisers in third world countries.
http://news.scotsman.com/scitech.cfm?id=92342004