From ABC News, writer Anna Salleh attended a speech by Dr Sanchez in Sydney.
"A lot of the public opinion still feels that Africa is a basket case. It cannot feed itself," says Dr Sanchez, of Columbia University's The Earth Institute in New York.
"I think that needs to change."
Expanding on a recent article in Nature Geoscience, Dr Sanchez argues tropical Africa is capable of tripling its crop yields if something is done about the lack of nutrients in its soils.
"Food crop yields have not changed in Africa since 1961," he says. "That's 50 years. It's amazing."
Dr Sanchez says most of the soils cultivated by Africa's small farmers are "pretty decent", but have become depleted of nitrogen, and to a lesser extent phosphorous.
"The soils are not inherently bad as some people have said," he says.
"What happened is that farmers took out too many nutrients, mainly in the form of crop harvests."
He says the same thing happened after 100 years of farming in the US Midwest, which has some of the best soils in the world.
While he sees GM crops as part of the solution to feeding Africa, Sanchez says the focus of donor agencies, like the World Bank, on improved crop varieties has missed the importance of soils.
"If the fertilisers aren't there, there is no way you can have high-yielding varieties reaching their potential," says Dr Sanchez.