Prehispanic agricultural terrace-settlement systems: an integrative approach to study land use and settlement dynamics in the southern Peruvian Andes

An impressive relic of the scale of human-environment interaction and land modification in prehispanic South America are agricultural terraces, covering slopes across the Andes and of which only a fraction is still in use nowadays. Despite the ubiquity of agricultural terraces in the Andes, there is a lack of systematic studies that combine the investigation of farming terraces, land use history, and settlement patterns, preventing a comprehensive understanding of prehispanic socio-economic-ecological systems and human-environmental interactions. Our project develops and applies an integrative and interdisciplinary methodological approach to the study of prehispanic Andean terrace agricultural systems and associated settlements, providing reliable data on the dynamics of land use-settlement systems through time and space. Our methodological approach consists of the application of a variety of archaeological and geoscientific methods, including archaeological and geomorphological surveys, archaeological excavations, drone surveys, mapping using satellite imagery and high-resolution digital elevation models, geographic information system applications, soil testing, phytolith and starch analysis, numerical dating, and calculations of food supply capacity and labour requirements.

We apply these to the prehispanic site of Cutamalla (3,300 m asl) in the southern Peruvian Andes, which serves as an ideal and pioneering case study. Previous research has focused primarily on the settlement of Cutamalla, particularly through large-scale archaeological excavations, but less attention has been paid to the extensive farming terraces surrounding the settlement and the close relationship between agricultural and settlement activities. By analyzing both the terrace and settlement levels, we take a new perspective and introduce the term agricultural terrace-settlement system for such complexes. Our results show that the residential occupation of Cutamalla and the use of the surrounding farming terraces coincided: the agricultural terrace-settlement system was intensively used for a relatively short period of about 200 years (~250–40 BCE) during the Formative Late Paracas and transitional Initial Nasca periods. There is no evidence of reoccupation of the site and subsequent reuse of the agricultural system. Our data also document the large extent of agricultural terraces around Cutamalla (221 ha) and that maize was likely a major crop grown there. Finally, we place these findings in their broader socio-economic and ecological context. Cutamalla was an important regional center and economic hub during a very dynamic period characterized by significant population growth and increased violence. Not only a more humid climate, but probably also forced collective labor were cornerstones of substantial agricultural production in Cutamalla and the region.