Growing food in the desert: is this the solution to the world's food crisis?

Philipp Saumweber is creating a miracle in the barren Australian outback, growing tonnes of fresh food. So why has he fallen out with the pioneering environmentalist who invented the revolutionary system? The scrubby desert outside Port Augusta, three hours from Adelaide, is not the kind of countryside you see in Australian tourist brochures. The backdrop to an area of coal-fired power stations, lead smelting and mining, the coastal landscape is spiked with saltbush that can live on a trickle...