The ancient agricultural landscape of the satellite settlement of Ramonal near Tikal, Guatemala

Soil science methodologies often enrich archaeological reconstructions. In the Maya Lowlands of Mesoamerica, stable carbon (C) isotope ratio (δ ¹³C) analysis of soil organic matter (SOM) from profiles near ancient archaeological sites has been used to interpret the vegetative histories related to ancient maize agriculture. Due to distinct photosynthetic processes, the decomposed organic matter from the cultivation of maize can be distinguished from SOM derived from native forest detritus. The recalcitrant nature of humic substances allows for this distinction to be preserved through time. This study evaluates SOM δ ¹³C from 98 soil profiles near Tikal, Guatemala to identify areas of ancient Maya agriculture and the staple crops used. Ancillary physical and chemical properties of the soil profiles were examined to facilitate and to supplement the interpretation of the isotope data. Most of the soils analyzed in this study are shallow Haprendolls with limited C isotopic evidence of prehistoric vegetation changes. The deeper, well-developed Argiudolls and Hapludolls contained strong evidence of vegetation changes associated with ancient maize agriculture. Areas with strong δ ¹³C signatures of ancient C ₄ vegetation corresponded with foot- and toeslope locations, high clay content and low phosphorus (P) levels. The shallow backslope soils lacked significant evidence of ancient agriculture. The connections between profile location, settlement, isotope data, and P levels enable the identification of both agriculture production zones and enhanced understanding of stable C isotope dynamics in soils within the unique physiographic and archaeological surroundings of the Maya Lowlands.