section_path: Economy/Agriculture and subsistence
section_name: Agriculture and subsistence
paragraph_text: Agriculture and subsistence
  
  Like all Mesoamerican peoples, Aztec society was organized around maize agriculture. The humid environment in the Valley of Mexico with its many lakes and swamps permitted intensive agriculture. The main crops in addition to maize were beans, squashes, chilies, and amaranth. Particularly important for agricultural production in the valley was the construction of chinampas on the lake, artificial islands that allowed the conversion of the shallow waters into highly fertile gardens that could be cultivated year-round. Chinampas are human-made extensions of agricultural land, created from alternating layers of mud from the bottom of the lake, and plant matter and other vegetation. These raised beds were separated by narrow canals, which allowed farmers to move between them by canoe. Chinampas were extremely fertile pieces of land, and yielded, on average, seven crops annually. Based on current chinampa yields, it has been estimated that one hectare (2.5 acres) of chinampa would feed 20 individuals and 9,000 hectares (22,000 acres) of chinampas could feed 180,000.
  
  The Aztecs further intensified agricultural production by constructing systems of artificial irrigation. While most of the farming occurred outside the densely populated areas, within the cities there was another method of (small-scale) farming. Each family had a garden plot where they grew maize, fruits, herbs, medicines, and other important plants. When the city of Tenochtitlan became a major urban center, water was supplied to the city through aqueducts from springs on the banks of the lake, and they organized a system that collected human waste for use as fertilizer. Through intensive agriculture, the Aztecs were able to sustain a large urbanized population. The lake was also a rich source of proteins in the form of aquatic animals such as fish, amphibians, shrimp, insects and insect eggs, and waterfowl. The presence of such varied sources of protein meant that there was little use for domestic animals for meat (only turkeys and dogs were kept), and scholars have calculated that there was no shortage of protein among the inhabitants of the Valley of Mexico.