Africa owns 60% of the world's uncultivated land suited for crop production, but accounts for 30% of the world's malnourished and only 3% of global agricultural exports. If there is one thing global agricultural policy experts Paul Collier and Derek Byerlee can agree on, it's that Africa's food system is struggling.Their different views on the causes and investment solutions to put Africa on a more prosperous and food secure path made for a provocative discussion at a symposium hosted last week by Stanford University's Center on Food Security and the Environment.