Mapping Pre-Colonial African Agricultural Systems

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Recent attempts to map the history of global land cover underestimate the development of sub-Saharan African agriculture prior to colonialism. Furthermore in most categorizations of African agricultural systems the assumption has been that shifting cultivation was the norm, and that African agriculture changed little over the centuries. Several strands of on-going research question this image of extensive farming with few technological changes over time . It has, for example been shown that shifting cultivation involved a number of different and dynamic farming systems that changed over time. Moreover, a number of areas in Africa were characterized by intensive cultivation (terracing, manuring and/or irrigation) that predates European colonization. The antiquity of these systems is unknown, but the existence of ancient centralized societies indicates that agricultural production and intensity must have reached high levels. This paper presents the first continent-wide overview of the development of farming landscapes during the past millennium and will present a dynamic picture of farming systems and land use responding to societal changes. During the whole last millennium agriculture expanded in Southern Africa, while a retreat southwards along the Sahel zone can be documented in some areas. The first millennium also saw the establishment of the intensive banana-based agriculture in the Great Lakes area, connected to the development of centralized kingdoms. After the Columbian exchange the introduction of the American crops, notably maize and cassava (manioc) offered possibilities for an intensification of agriculture in the humid and subhumid zones. This expansion seems to be spurred by developing Atlantic trade. Paradoxically the period of the intensive slave trade, was contemporaneous to an intensification of agriculture in West Africa. The development of farming systems of that time is closely connected to the increase of slave raiding, slave trade and trade in other products. There existed a dialectical relationship between centralized states involved in the slave raiding and decentralized communities trying to evade slave raiding. While the former used slaves in the development of intensively manured infield-outfield systems along the semi-arid savannah zone, especially in northern Nigeria, the later developed intensive farming systems with terracing and manuring in highlands or expanded irrigated rice cultivation in the coastal zone