Farmers who grew crops on the very banks of the river or the shores of the lake or swamp were always at the mercy of devastating floods or droughts. When they succeeded in controlling the water, however, the results were spectacular. Whereas Neolithic farmers in the Middle East might hope to reap four or fi ve grains of barley for every grain they planted on rain-watered land, in a river valley, a grain of barley receiving the right amount of water during the growing season could yield up to forty grains.
The farmers who settled closest to the rivers could depend on periodic floods to water their fields. Those who came later, however, settled further from the riverbanks. To bring water to their fi elds, they had to dig canals, dikes, and other earthworks. Building and maintaining these works required the labor of hundreds, even thousands, of men directed by a cadre of supervisors. Although farmers had to contribute their labor, they were not slaves driven by men with whips. People obeyed because they realized the need to work together, because of the peer pressure of their neighbors, and because they were afraid that refusing would bring down the wrath of the gods. Moreover, they knew that they had nowhere else to go. In rain-watered environments, people could wander off seeking new land, but in desert regions, survival was impossible outside the river valleys.
The place where the first civilization arose was Iraq, a land the Greeks called Mesopotamia, the “land between the rivers” Tigris and Euphrates. The valley has good alluvial soil but is difficult to farm. It is very hot and dry in the summer and cold and dry in the winter. Although little rain reaches the valley, in the spring water rushes down from the mountains to the east and north when the snows melt. The rivers carry a great deal of silt that gradually raises them above the surrounding plains until they overfl ow their banks in devastating floods. All the peoples of the region told legends of the flood, most famously the Hebrew story of Noah’s Ark told in the Bible (Genesis 5–9).
To the Neolithic farmers who lived in the surrounding hills, the flood plain presented both an opportunity and a challenge. By the sixth millennium bce, the bolder ones were moving down into the plains and building villages. By the fi fth millennium, they were digging short feeder canals to irrigate their fields and drain excess water. To keep the floods from washing away their crops, they built dikes. To hold some of the water back when the fl oods subsided in the summer when the crops needed water the most, farmers built small reservoirs. Keeping the water flowing was a constant task because silt clogged the canals and the salt and gypsum it contained would poison the fi elds if they were not properly drained. As the population grew, farmers drained marshes and built canals and reservoirs ever farther from the rivers, requiring ever larger work crews. Success depended on good leadership and the cooperative work of thousands.
Food Resources in Early Civilized Societies and Development of Technologies
