Development of Plant Food Production in the West African Savannas: Archaeobotanical Perspectives

The West African savannas are a major area of independent plant domestication, with pearl millet, African rice, fonio, several legumes, and vegetable crops originating there. For understanding the origins of West African plant-food-producing traditions, it is useful to have a look at their precursors in the Sahara during the “African humid period” between 10,500 and 4,500 years ago. The Early and Middle Holocene Saharan foragers and pastoralists intensively used wild grasses for food but did not intentionally cultivate. Due to increasing aridity in the late 3rd millennium bce, the pastoralists migrated southward into the savanna zone. In this context pearl millet was domesticated and spread rapidly in West Africa during the 2nd millennium bce. It was first cultivated by agro-pastoral communities, predominantly on a small scale. The 1st millennium bce was a transitional phase: most of the early agricultural societies disappeared, but it was also a time of numerous economic and social innovations. Due to increasing aridity, the floodplains around Lake Chad and the valleys of the rivers Senegal and Niger became accessible to farming populations after 1000 bce. In the 1st millennium ce, agriculture intensified, with mixed cultivation of cereals and legumes and the integration of new African domesticates, such as sorghum, fonio, roselle, and okra. Pearl millet remained the major crop in most areas, while sorghum dominated in northern Cameroon. Imported wheat, date palm, and cotton appeared in the first half of the 2nd millennium ce. The combined exploitation of cultivated cereals, legumes, and wild fruit trees (e.g., shea butter tree) in agroforesty systems eventually resulted in a cultural landscape as it is still visible in West Africa today.