The Columbian Exchange left significant marks on African history and society, arguably nowhere more than in the introduction of American food crops, which occurred within the context of Portuguese trade in slaves and commodities and the development of a broader Atlantic economy. Subsequent increase in the cultivation of these crops is inseparable from population growth and the development of commercial agriculture. Today, though pre-Columbian African crops such as rice, sorghum, and millet continue to be important on the continent, American crops have eclipsed them.
MAIZE
Claims have been made for the pre-Columbian origin of maize, either as an indigenous crop or as evidence of earlier contact between Africa and the Americas. However, despite lack of precise evidence for the dating of maize’s introduction, most scholars concur that maize was introduced in the sixteenth century either by the Portuguese or by trans-Saharan Arab traders. The Portuguese required cheap, storable, and local food sources to support the slave trade, and maize served this need, becoming the principal food of slave ships. The crop’s spread in the sixteenth century is poorly mapped, though contemporary reports suggest a fairly wide diffusion and growing adoption by Africans. African horticulture was amenable to experimentation, allowing intercropping and therefore the dedication of part of a garden plot to new crops. The advantages of maize over African crops such as sorghum and millet were soon recognized by African agriculturalists; maize can be eaten immature, gives higher yields, renders more calories per acre, and is less prone to bird damage. By the seventeenth century the crop had spread to interior sites including the Congo Basin and Senegal River Valley, and there are also reports of its cultivation in East Africa. Maize is generally reckoned to have enabled population expansion; certainly it enabled the slave trade, both by providing a cheap food source to feed slaves and, possibly, because crop failures produced displaced and saleable populations. Maize also had political implications; for example, it furthered the hegemony of groups such as the Asante of Ghana. Travelers’ reports from the eighteenth century confirm the spread of maize deep into the interior of western Africa. By the end of the 1800s maize was found virtually everywhere in sub-Saharan Africa with the exception of Uganda. Its current status as the core dietary staple in much of eastern and central Africa, however, was a later development enabled by the growth of large-scale commercial farming. The history of maize in Africa is thus a narrative of growth from its origins as a cheap food linked to the slave trade to its current status as (perhaps fragile) mainstay of many African diets.
MANIOC (CASSAVA)
Manioc or cassava is another American crop whose importance continued to grow from the sixteenth century to the twentieth. Like maize, manioc was originally introduced by Portuguese traders as a food suitable for feeding slaves and spread quickly with the growth of the trade in human beings. Native to tropical America, manioc is well suited to tropical African conditions, as it tolerates poor soils, resists drought and locust attack, and stores well. Its superiority to maize in these regards led to its supplanting that crop in tropical regions where maize gained early acceptance, such as the south-central Congo Basin. However, manioc spread more slowly; despite cultivation in Angola in the sixteenth century, there is no contemporary evidence for manioc planting on the Guinea Coast. Nonetheless, by the seventeenth century manioc was spreading through west central Africa. Adoption was slower elsewhere; anecdotal reports of manioc poisonings in East Africa may suggest good reason for greater caution. Indeed, despite widespread Amerindian development of toxin-eliminating processing techniques, in Africa manioc was sometimes fed to slaves in a minimally processed form. Overall, however, manioc produced declines in infant mortality in African communities and increased the possibility of survival during times of drought. Like maize, manioc thus furthered population increase but did not completely end the cycles of drought and crop loss that often led to the sale of individuals into slavery. Thus this ”agricultural revolution” enjoyed an ironic symbiosis with the slave system. Manioc’s spread continued after the eighteenth century and into the modern era. Though manioc has not experienced a recent dramatic growth in cultivation as seen in the case of maize, manioc is the most widely planted crop in tropical Africa, the continent’s second most important food crop, and a cherished cultural tradition despite its foreign provenance. Tropical Africa is the world’s leading producer of manioc, which remains at the core of Africa’s hopes for food self-sufficiency and economic growth.
OTHER CROPS
Other American crops were introduced during the period of Portuguese trade, though the exact circumstances of their introduction are even more clouded than those surrounding the introduction of maize and manioc. American groundnuts or peanuts were introduced and became an important source of protein as well as an important cash crop for small producers; tomatoes, avocados, squash, beans, papayas, pineapples, guavas, and chilies had varying impacts on the diet of different regions, and were all enthusiastically adopted in the cuisines of West Africa. Sweet potatoes, however, have had greater impact than any of these crops, in some places attaining the status of a staple crop and contributing significantly to total caloric intake.
The introduction of American crops continued into the modern period in the context of global market competition in the agricultural sector. In the nineteenth century, vanilla was introduced to Madagascar, which is today a much more significant producer than vanilla’s Mesoamerican homeland, though it is facing vulnerability to new sources of competition. Cacao was introduced to West Africa at the end of the nineteenth century to compete with American production; though the region is now the largest producer of cacao, its cultivation has brought deforestation and vulnerability to fluctuations in the world market. Cacao production has also revived the association of American crops with slavery, as child slavery has recently been reported in Ivory Coast cacao plantations. American crops have thus had an ambivalent history in Africa; they have been central to the sustenance of the African population, but have also often been associated with a more general history of domination.
Cassava Processing in Madagascar. A man dries cassava in a village near Betioky in Madagascar in 2000. The cassava plant, which is native to South America, was brought to Africa by Portuguese traders.
