“…This, however, ignores the significant differences in the quantity of labor required to grow and harvest each plant. Of the staple crops in Africa, maize has the lowest labor requirements (Purseglove, 1972;Hogendorn andGemery, 1990-1991;McCann, 2001), particularly after processing, storage and transport are taken into account (Miracle, 1966). Given that a hectare of maize has a similar energy content to a hectare of cassava or sweet potatoes, this suggests that maize was the most productive of the New World crops introduced into Africa, and had the greatest potential to create an agricultural productivity shock.…”