Ancient Mesopotamia, the drainage basin of the Tigris and Euphrates Rivers, where agriculture and urban societies first developed, was divided ecologically into two zones the southern irrigation agriculture zone of Sumer and Akkad in southern Iraq, and the northern dry-farming zone of Subir, across northern Iraq and Syria. ArcheoSim simulates growth, collapse, and resettlement in Subir using real archeological survey data, from 2600-1728 BC, including regional responses to megadrought in Subir at 2200 BC.
Rain-fed cereal cultivation in this area was bounteous and extensive, across low-rolling plains similar to the Ukraine and Kansas. Essentially, all grain was grown for the state, and stored by the state. People were paid rations of grain based on their needs and the kind of work they did.