Simulating the Effects of Salinization on Irrigation Agriculture in Southern Mesopotamia

A model of irrigation agriculture is applied to southern Mesopotamian for the areas around Nippur and Uruk. Field systems around late third millennium BC (Ur III period) cities are modeled in order to understand the effects of salinization and what strategies might limit progressive salinization that hinders agricultural yields. Scholars have long suspected that progressive salinization may constrain irrigation agriculture in southern Mesopotamia. This is not only demonstrated by modeling, but methods to mitigate the effects of salinization and promote the resilience of agricultural systems are presented. Strategies that incorporate fallowing regimes and which promote natural and/or engineered leaching create resilient agricultural systems in which ancient farmers could have made decisions about when to crop and irrigate based on the effects of salinization. Simulation results not only demonstrate to what extent and under what conditions salinization could be limited, but also model results indicate that irrigation-induced salinity could have ultimately become a major constraint to settlements and agriculture in southern Mesopotamia.