Weed survey and isotope sampling in Morocco

Our route through Morocco

In March, the AGRICURB team carried out fieldwork in Morocco, accompanied by colleagues Professor Mohammed Ater and Dr Younes Hmimsa from the Université Abdelmalek Essaâdi, Tétouan. The team spent 10 days travelling through Morocco and conducting weed and crop isotope surveys of organic cereal fields managed under different agronomic regimes, from highly intensive oasis ‘gardens’ to extensively managed fields. The Moroccan fieldwork offers us a range of agronomic regimes across a contrasting set of climatic conditions, from the mediterranean north to the extreme aridity of the ‘portes du désert’ in the south. This range of agronomic practices under semi-arid to arid conditions is directly relevant to our archaeological sites in the Aegean, such as Knossos, and in south-west Asia, such as Tell Brak.

The first stop was the Rif region in the north of Morocco, where we assessed the potential for a return trip in late May when the crops are ripe (more about this soon…). This was followed by a drive through the High Atlas region, with stops en-route to see intensive high-altitude alluvial cereal farming, watered by the spring snow melt, and down towards Tata, where opportunistic floodplain cultivation is practiced on the rare occasions that rain falls in this otherwise desert-like landscape.

The final goal was to visit oases in the south of Morocco, around Tata and further to the west, where the permanent groundwater supply allows intensive cereal farming in the shade of date palms. These permanently irrigated, intensively manured and hand-worked fields contrast with rain-fed, extensively managed terrace agriculture practiced on the southern slopes of the Anti-Atlas Mountains nearby. In all of these regions, ecological analysis of the weed surveys combined with stable carbon and nitrogen isotope analysis of crop samples collected here will enable us to assess the impact of varying agronomic practices under (semi-)arid conditions, and improve our ability to recognize such cultivation practices in the archaeological record.

Weed survey in the oasis

Provence weed functional ecology survey and isotope sampling concluded

A twelve-person AGRICURB team completed a trip to the south of France in early July 2013 to conduct a weed survey and take crop samples for isotopic analysis. The team, led by Amy Bogaard, visited nearly 60 fields of organically-grown einkorn, barley, wheat and lentils in the region of Vaucluse and the Lubéron National Park. In cooperation with local farmers, the team documented the traditional agricultural methods being used and surveyed the weed species found along a transect within each field. Species were identified by John Hodgson and Glynis Jones, assisted by Charlotte Diffey, Laura Green and Hyunyoung Kim, and specimens were collected to make functional attribute measurements back in the UK. This will allow the team to link the crop growing conditions of fields in Provence to the types of weed present, ultimately allowing us to recognize very extensively maintained growing conditions based on the functional characteristics of weeds that are identified in the archaeological record. At the same time, Amy Styring and Erika Nitsch took samples of crops, hedgerow plants and water for carbon, nitrogen and strontium isotope analysis in order to understand how within-field variability might affect interpretations of isotopic measurements of archaeobotanical crops. The mapping and spatial design of the entire survey was coordinated by John Pouncett.

PNAS paper available in Early View

“Crop manuring and intensive land management by Europe’s first farmers” (by Amy Bogaard, Rebecca Fraser, Tim H. E. Heaton, Michael Wallace, Petra Vaiglova, Michael Charles, Glynis Jones, Richard P. Evershed, Amy K. Styring, Niels H. Andersen, Rose-Marie Arbogast, László Bartosiewicz, Armelle Gardeisen, Marie Kanstrup, Ursula Maier, Elena Marinova, Lazar Ninov, Marguerita Schäfer, and Elisabeth Stephan) is now available in Early View from PNAS.

Abstract:

The spread of farming from western Asia to Europe had profound long-term social and ecological impacts, but identification of the specific nature of Neolithic land management practices and the dietary contribution of early crops has been problematic. Here, we present previously undescribed stable isotope determinations of charred cereals and pulses from 13 Neolithic sites across Europe (dating ca. 5900–2400 cal B.C.), which show that early farmers used livestock manure and water management to enhance crop yields. Intensive manuring inextricably linked plant cultivation and animal herding and contributed to the remarkable resilience of these combined practices across diverse climatic zones. Critically, our findings suggest that commonly applied paleodietary interpretations of human and herbivore δ15N values have systematically underestimated the contribution of crop-derived protein to early farmer diets.

There is more information available from the School of Archaeology News page at the University of Oxford.