Nahua plant knowledge and chinampa farming in the Basin of Mexico: A Middle Postclassic case study.

Abstract

The development of states with large non-agrarian urban centers required a dependable and abundant food supply. Chinampa agriculture, the system of raised fields in the swampy lakes of the Basin of Mexico, was a remarkable, intensive agriculture that provided food for Tenochtitlan, the capital of the Aztec empire. This study examines the complexity of chinampa agriculture to increase our understanding of the development of chinampa farming and its economic significance in prehispanic times. The primary archaeological data are plant remains collected from Ch-Az-195, a Middle Postclassic (A.D. 1150-1350) chinampa settlement in Lake Chalco. A reconstruction of Nahua plant knowledge, land use, and strategies for plant collection and cultivation was developed using linguistic, ethnohistoric, ethnographic, ecological, and contemporary botanical information. Applying this reconstruction to prehispanic times required examining changes in natural and cultural conditions in the Basin. Taking into account changes in population growth, urbanization, political integration, tribute demands, and the market system between the Middle and Late Postclassic periods, it is suggested that stable and predictable yields were more important than large yields in Middle Postclassic times. Consequently, Middle Postclassic chinampa agriculture was less intensive, the chinampa economy was less specialized, and exchange systems more informal. Using estimates of nutritional and other plant needs from Ch-Az-195, predictions are made about the nature of chinampa farming, plant use, and land use at that site. The plant remains provide evidence of many economic activities, including chinampa farming, collecting of non-domesticated food plants, mat-making, collecting of Piedmont fruits, and spinning cotton. Quantitative analysis of the remains suggests that agriculture was less intensive than in Late Postclassic times, but was sufficient to supply the needs of the Ch-Az-195 population. A shift to more intensive agriculture could have resulted from internal changes at the settlement and from economic and political forces from outside.