Environmental settings of agricultural practices in central Italy during the first half of the first millennium BCE

One of the main transformations in the western Mediterranean is the birth and surge of urban life during the first half of the 1st millennium BCE. This urbanization process is usually linked with an intensification of food production and changes in agricultural practices. However, it is not well known how the relationships between their different parameters were reshaped during this period. This phenomenon was observed in Central Tyrrhenian Italy from the Bronze Age to the Archaic period (12th to 6th c. BCE). Over the span of a few centuries the sparse clusters of huts observed during the Bronze Age evolved into city-state urban centers such as Rome or Tarquinia. Some of the aspects of these changes are still under debate including what kind of agricultural practices sustained the development of these early urban centers. Importantly, there is much that we do not know about possible environmental factors that could have triggered or influenced these processes in multiple and complex ways. Climatic instability has been reconstructed for this period but its role in the social cultural development of the region has not yet been assessed. The present research question lies in the interplay between environment, climate, agriculture and urbanization processes that occurred in Central Tyrrhenian Italy during the first half of the 1st millennium BCE. Three archaeological sites that underwent this process of urbanization (Palatine Hill located in Rome, Gabii and Tarquinia) were selected for this study. They all provided charred archaeobotanical material (seeds, fruits and wood) dated from the 10th to the 5th c. BCE. Two complementary methods were used to answer the research question: The first was the study of the archaeobotanical material which informs on crop production; The second was the use of carbon and nitrogen stable isotope analysis. This innovative method helps to gather information about the field environment and management. Specifically, it allows us to study the water availability in which plants grew with the measure of the Δ13C as well as to identify possible application of manure through the δ15N results. The archaeobotanical study resulted in a total of about 30400 seeds, fruits and fragments from the three archaeological sites. The analysis showed a dominance of cereals, with barley and emmer being the main staples. Pulses were the second most important category represented mainly by fava beans and bitter vetch. Some differences in the proportions of crops were identified among sites suggesting cultural or economic preferences since the three sites lie in the same environmental region. Weeds of arable fields, which are good environmental indicators, were also identified in large quantities but due to their ubiquity, they were not discriminant. Carbon and nitrogen stable isotope analyses (δ13C and δ15N) were performed on 557 charred barley and emmer caryopses from the three archaeological sites. The results show some variation in water availability across time for both species. The δ15N values are, overall, low and no difference across time or periods was identified. This suggests that no manuring practices were commonly used during this period. A pilot study on 270 fragments of wood charcoal from Gabii to reconstruct the environment of the spontaneous flora in the region. Taxonomic identification shows a prevalence of deciduous oak forests and the surprising presence of beech which, according to the regional paleoenvironment studies, should not be present anymore in low altitudes. Ten charcoal fragments of deciduous oak were selected for isotope analysis. They were radiocarbon dated (14C) and δ13C was calculated to explore past natural environmental water availability. The comparison with the trends identified in the crops is used to discriminate environmental from anthropic factors. The14C results obtained show a large range in terms of dating which was expected as the period of interest falls into the Hallstatt plateau, a flat area between the 9th and the 5th c. BCE on the reference curve used for calibration (Trias et al. 2020). This makes it challenging to put the charcoal fragments in sequence and consequently compare their trend with the cereal ones. Different methods to overcome this are currently being explored and the addition of more charcoal fragments should help. It is the first time that this kind of work is undertaken in this region and for this period. It represents an innovative work which contributes greatly to the understanding of the complex mechanisms and evolution occurring during this period.