Explain why dry farming was the ancient mesopotamians’ preferred method of farming. what eventually made dry farming more difficult?

Dry farming occurs is areas where there is little rainfall. Mesopotamians depended on the annual flooding of the Tigris and Euphrates Rivers. This is similar to the Egyptians depending on the Nile to flood. The annual flooding was more predictable than expecting rainfall. The problem with this style of farming is that rivers move and dry up. Should a great drought occur then even the flooding won't be enough to keep crops growing. 

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