They measure how much was irrigated in two medieval agricultural areas of the Basque Country

Most of the information available today on agriculture in the Middle Ages comes from written sources, which mainly cover the last centuries of the period and do not offer precise information.

A team, in which the University of the Basque Country has participated, has used an unprecedented methodology in medieval sites on the Iberian Peninsula with which it has been possible to obtain agricultural data on the entire Middle Ages and on contexts for which data were not available. direct written evidence.

This is highlighted by Maite Iris García Collado, postdoctoral researcher in the Archeology Area of ​​the University of the Basque Country / Euskal Herriko Unibertsitatea (UPV/EHU), who is currently on a stay at the University of York. The results of this study have recently been published, based largely on the analysis of stable isotopes of carbon and nitrogen in 50 seed samples from the medieval sites of Zornoztegi and Aistra (Álava), dated between the 4th and 14th centuries AD.

“With these data we have been able to determine the levels of irrigation and fertilization that were practiced -explains García Collado-.

The study has also helped to reconstruct the agrarian practices of medieval societies in the area.

This technique makes it possible to quantitatively characterize the agricultural practices of the past, especially with regard to water availability and fertilization. In addition, it is the first time that the methodology has been systematically applied to medieval sites in the Iberian Peninsula. “Thus we can affirm that in the medieval settlements of Zornoztegi and Aistra wheat and barley were cultivated, characterized by low and moderate levels of irrigation and practically null fertilization. Even so, the wheat samples suggest that the selection of plots with greater water availability or human interventions to improve it was greater in the village of Zornoztegi than in Aistra”.

Charred wheat seeds from the medieval site of Zornoztegi. (Photo: Maite Iris García Collado)

On the other hand, this research also presents indications of the possible application of crop rotation using legumes to fertilize soils since the High Middle Ages. These results, which reveal hitherto unknown aspects of the agrarian strategies adopted by medieval rural communities, encourage further work on this topic, analyzing larger data sets and expanding the case studies geographically and chronologically.

“Other interesting things we have discovered are important differences between the two sites, which help us understand the economic, social and political roles of each. Zornoztegi was a peasant village in which there are no differences between family groups, while Aistra was a central place in the region where there are indicators of the presence of local elites and which probably served as a tax collection center. Initially we thought that the seeds found in Aistra, coming from rents, would have been more diverse. However, the variability was similar in both contexts and we even observed a possible greater investment of work in those of Zornoztegi. However, the lack of isotopic data on agricultural practices during Roman times has limited our research, which would have been essential to adequately assess the changes and innovations that occurred during the Middle Ages”, concludes the researcher.

The study is entitled “First Direct Evidence of Agrarian Practices in the Alava Plateau (Northern Iberia) During the Middle Ages Through Carbon and Nitrogen Stable Isotope Analyzes of Charred Seeds”. And it has been published in the academic journal Environmental Archaeology. (Source: UPV/EHU)