Measured as an average yield in calories per hectare (a hectare is ten thousand square meters, the equivalent of 2.5 acres), cassava (9.9 million), maize (7.3 million), and potatoes (7.5 million) all trump the traditional European crops: wheat (4.2 million), barley (5.1 million), and oats (5.5 million). By introducing the New World crops to the Old World, the colonizers dramatically expanded the food supply and their population.
