Concept
Chinampa (chināmitl tʃiˈnaːmitɬ) is a technique used in Mesoamerican agriculture which relies on small, rectangular areas of fertile arable land to grow crops on the shallow lake beds in the Valley of Mexico. They are built up on wetlands of a lake or freshwater swamp for agricultural purposes, and their proportions ensure optimal moisture retention. The United Nations designated it a Globally Important Agricultural Heritage System in 2018. Although different technologies existed during the Post-classic and Colonial periods in the basin, chinampas have raised many questions on agricultural production and political development. After the Aztec Triple Alliance formed, the conquest of southern basin city-states, such as Xochimilco, was one of the first strategies of imperial expansion. Before this time, farmers maintained small-scale chinampas adjacent to their households and communities in the freshwater lakes of Xochimilco and Chalco. The Aztecs did not invent chinampas but rather were the first to develop it to a large scale cultivation. Sometimes referred to as "floating gardens," chinampas are artificial islands that were created by interweaving reeds with stakes beneath the lake's surface, creating underwater fences. A buildup of soil and aquatic vegetation would be piled into these "fences" until the top layer of soil was visible on the water's surface. When creating chinampas, in addition to building up masses of land, a drainage system was developed. This drainage system was multi-purposed. A ditch was created to allow for the flow of water and sediments (likely including night soil). Over time, the ditch would slowly accumulate piles of mud. This mud would then be dug up and placed on top of the chinampas, clearing the blockage. The soil from the bottom of the lake was also rich in nutrients, thus acting as an efficient and effective way of fertilizing the chinampas. Replenishing the topsoil with lost nutrients provided for bountiful harvests. Embarcadero-Jiménez and colleagues tested the correlation between environmental parameters and bacterial diversity in the soil.