suspected of challenging with food production . ‘’ As a potential biofuel , this is essentially gold dust ,’’ says Dr Fernie . “ It grows not only on marginal land but land that is completely ruined for agricultural use .” In South Africa , at least , it won ’ t be food-versus-fuel , but fuel-versus-smokes – and Solaris could also be used in rotation on the 70,000 hectares of cotton plantations in the country , says Dr Tommasini .