Reading ‘Africa – A Biography of a Continent’, a book by John reader has been really enlightening. I have learnt that both maize and cassava were introduced to African agriculture by the Portuguese during the 16th century. I always thought Cassava was indigenous to Africa. The crops were initially introduced along the west African coast and it appears that their dissemination was rather slow. Neither of them contributed significantly to the subsistence diet before 18th century.
Cassava was more advantageous to African agricultural communities than maize. Capable of producing harvestable tubers at any altitude from seal level to 1800 metres, in soils ranging from rainforest humus to savannah sands, with rainfall ranging from 800mm to 9000mm per year, cassava broadened food-production opportunities in every habitat farmers occupied. Furthermore it was readily propagated from short lengths of stem simply stuck into the ground and its mature tubers could be left underground for up to two years or more. No other African crop could be stored for for so long, and at times of violent social transformations it was better to have crops in the ground than grain in the granary, where raiders could find it. For these reasons cassava became popular among African communities.
Maize also offered storage advantages, but its greatest attraction was high productivity, the absence of indigenous pests, and a husk which protected the cobs from birds. By the virtual of these features maize could provide nine times more grain per unit of labour than either millet or sorghum, but only where soils are sufficiently fertile and well watered. Unlike cassava, maize cannot tolerate poor soils and drought.