Stable isotopic evidence for land use patterns in the Middle Euphrates Valley, Syria.

The depletion in 15 N from the Neo-Assyrian period onwards is best explained in terms of a shift from intensive to extensive farming, triggered by the fall of regional city-states after the Old Babylonian period and the formation of large supra-regional polities in the Neo-Assyrian period and later. The enrichment in 13 C during the Modern period was most likely the effect of more widely utilizing the dry steppes, abundant in C4 plants, as pasture.