Early Mesopotamians turned to dry farming because

Early Mesopotamians turned to dry farming because of the climate there which was dry with so little rainfall. It was the seasonal floods that made their soil fertile. F armers depended on the flooding of the Tigris and Euphrates rivers to have water for their crops. It was the silt that was left behind from the flooding water that made the soil fertile ... The most important crops in Mesopotamia were wheat and barley.