History of Irrigation- Part 1.docx

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Agricultural Studies
AGST 1000
Henning Bjourlund

History of Irrigation Part 1 Hydraulic Societies - Major Irrigation Societies o Agriculture the basic of Cultivation Irrigation - Irrigation systems o Surface water diversions o Groundwater mobilization systems - Diffusion of irrigation systems Population pressure forces cereal production into the dry plains - Settled agriculture started around 10,000 years ago in areas with sufficient rainfall - Increasing population forces cereal production into ‘The plains’ around 4,500BC - Needed to adapt to new conditions - Mediterranean climate regime of wet winters and dry summers - The seasonal contrast is especially marked in the lowlands - Remedy simple-dig ditches to divert water from the river during dry periods and prevent flooding during harvest - And the practice of ‘irrigation’ emerged - This profoundly changed the sue of land - They could grow two crops a year but it required both drainage and irrigation - Land not subject opt spring flooding could now also be turned into productive fields Mesopotamia: Canals on the Plain - Early watercourses and settlements in the Diyaya region. The system shown in grey was in use during the Early Dynastic period about 3,000-2,400 BC - Sites and watercourses slight displaces so that the earlier pattern will remain visible, were occupied during the Old Babylonian period, about 1,800-1,700 BC How it works - The canals opened up opportunities for settlement and irrigation - Settlement and settlement/reservoirs would be built Declining output - Evidence of a shift to dryer climate over a 300 year period from about BC 2200 - Caused further migration south from rain fed areas - Irrigation brought with it o A continued threat of soil degradation and o Insufficient irrigation because of shortage of water promotes salinization o Caused change in production from wheat to more salt resistant barely and decline in yields Transport of crops on the canals - Soil became more clay-rich and fine grained away from the levee crests - Additionally, the flood basins water logging led to salinization - However, the creation of these canals provided ideal ways for the transportation of crops - Any shortfall in production were alleviated b means of transport by boat as long as other settlements were providing a sufficient surplus Silting - Silting is the filing up or raising of the bed of a body of water by depositing silt - In Mesoplatamia, silt built up quickly in the canals threatening to choke them from a water supply. This could be overcome by dredging but labor was constantly needed. Salt and Silt in Ancient Mesopotamian agriculture - Around 3500 BC it appears that as much wheat as barely was grown in Southern Iraq - By 2500 BC wheat accounted for only one sixth of production - By about 2100 BC it accounted for no more than 2% of crops - By 1700 BC no wheat was grown at all, only barely which is more salt tolerant - Soil fertility also declined dramatically- largely as a result of water logging and salinity o In 2400 BC avgas 2,537kg o 2100 BC yield declined to 1,40kg o 1700 BC, avg 897 kg per hectare - The Nile o Length 6,700 km o Source  White Nile, Lake Victoria, Uganda  The Blue Nile: Lake Tan, Ethiopia  River Ataraba o Civilizations  7000BC: evidence of first farming village  3100 BC The Old Kingdom under the Pharaos Egypt’s Earliest Farming Village Found - The crops and animals- and techniques for raising tem- were all introduced to Egypt from the ancient Middle East, where domestication of plants and animals are known to have existed as far back as 9000BC - The 7000 year old farming village site includes evidence of domesticated animals and crops Water management under the Pharaohs 3,100 BC - Small canals feeding from the Nile would connect into small flat-bottomed basins and simple sluices in the dikes were used up to fill up and drain the basins A series of 200 Nilometer’s - “The man on the Nilometer” measured the increase in the Nilometer daily between afternoon and sunset - He also compared the increase in water level each day with the same day of the previous year Lifting water increased the area available for crop growing - The shaduf increased the quantity of the grain harvest because it increased the area of land available for crop growing The Indus Valley Civilization - The Indus River o 3,200km o Originating in the Tibetan Plateau - Civilzations o The oldest village, Mehgarh, 6,00BC o Harappa c. 3300-1300BC o Indo-Aryans c. 1700-600BC Indus Valley - Using a network of inundation canals aligned with natural drainage canals - Based on maintaining fertility by silt bearing floods - The canals flowed for 4-% Months during the monsoon-then as drainage canals - They did not cause water logging Loss of the River?? - 1800 BC sign of decline of Indus Valley Civilization and by 1700 BC most cities were abandoned - However elements still remained until around 900BCE - Why? o Possibly climate change significantly cooler and dryer o Part of the river disappeared to a tectonic event o Combination of causes Early Chinese irrigation - Three great rivers run through China the Yellow River in the north and the Yangtze in the center - Most of China’s traditional irrigated agriculture was and still in the drainage basins of these two rivers. Both originate to the f
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