To support their growing empire the Aztecs came up with clever ways to farm. They had irrigation systems causing them to have rich soil for farming. Since the Aztecs lived on an island in the middle of a lake and they soon ran out of farmland. The Aztecs soon came up with the idea of chinampas. These were little floating islands the Aztecs made by woven reed mats and on them was mud from the bottom of the lake that is rich with nutrients. The main way of trading was cacao beans.