Direct evidence for agricultural intensification during the first two millennia AD in northeast Burkina Faso

Abstract

Archaeobotanical evidence from archaeological sites in northeast Burkina Faso dating to the first and second millennia AD has provided a useful insight into crop cultivation and the development of the West African savanna landscape. Nitrogen isotopic analysis of charred pearl millet grains from the same sites now provides the first opportunity to investigate how increased crop production and permanence of cultivated fields related to the intensity of household waste/manure application. Nitrogen isotope values of pearl millet grains increased during the first two millennia AD, indicating an intensification of manuring that would have enabled soil to stay fertile for longer, reducing the agricultural footprint of shifting cultivation. This may have been advantageous as population and settlement density increased, thereby increasing competition over land. The intensity of manure application in the second millennium AD at sites close to the Mare d'Oursi suggests that manure was likely sourced from outside the farming settlements, from livestock herded by nomadic pastoralists who would have been drawn to the mare for water. This is rare evidence for specialisation of sedentary farmers and pastoralists, demonstrating how the novel combination of fruit/seed, charcoal, faunal and isotopic evidence used in this study can enrich our knowledge of past lifeways in West Africa.

Urban form and scale shaped the agroecology of early ‘cities’ in northern Mesopotamia, the Aegean and Central Europe

“…Crop nitrogen isotope values and use of a regression model that takes into account the effect of rainfall offer a ‘common currency’ with which to compare the intensity of agricultural practices in discrete geographic regions and [pre]historic periods. We hope that the application of this approach in other regions of the world (e.g., Styring et al, 2019 ) will help to provide a more nuanced insight into agricultural practice and how it intersected with politics and society more broadly over the longue durée . Alongside focus on the threat to agricultural sustainability posed by loss of species diversity, there needs to be a parallel discussion of how past agrosystems maintained a range of ecological niches if we are to maintain and promote biodiversity in the future (e.g., FAO, 2016 ).…”

Living in the dry zone: Stable isotope insights into palaeodiet in ancient Myanmar

“…Isotope analysis has become a fundamental tool for archaeologists and bioarchaeologists seeking to understand the lives and lifestyles of prehistoric individuals (Larsen, 2015). Significantly, stable isotope analysis of human tissues, animal remains, and plant remains has been increasingly used to explore questions relating to changes in diet, domesticate management, and environment linked to transitions in agriculture and settlement in different parts of the world (Styring et al, 2019, Vaiglova et al, 2020. In the context of human and animal remains, the methodology works on the principle of 'you are what you eat', whereby isotopic variation in food sources can be tracked into the tissues of their consumers (DeNiro and Epstein, 1976).…”