Final answer:
Chinampas agriculture is a method of ancient American agriculture used by the Aztecs, where small, rectangular areas of fertile arable land were used to grow crops in shallow lake beds. This technique allowed for careful control of soil fertility and watering, supporting a higher yield compared to other agricultural methods.
Step-by-step explanation:
The method of ancient American agriculture that used small, rectangular areas of fertile arable land to grow crops in shallow lake beds is called chinampas agriculture. This technique was practiced by the Aztecs in their island capital of Tenochtitlán on Lake Texcoco. Chinampas were raised planting-beds on floating platforms, allowing the Aztec farmers to carefully control soil fertility and watering. Through chinampas agriculture, the Aztecs were able to support six people per acre, which was much higher than the yield of Chinese intensive rice farming at the time.