Science et changements planétaires / Sécheresse


Histoire hydraulique et agricole et lutte contre la salinisation dans le delta du Nil Volume 6, issue 4, Décembre 1995

Orstom, Laboratoire d’études agraires, BP 5045, 34032 Montpellier cedex 1, France
  • Page(s) : 307-17
  • Published in: 1995

The Nile Valley can be thought of as an immense oasis whose existence depends on single water resource and shared along the length and breadth of the valley and its delta. For 5,000 years, the silt deposited by flooding and draining has provided the vital elements for soil fertility. Long-term irrigation systems are recent phenomena. From 1 820 to 1830, the Egyptian government decided to tackle the Nile’s low water level, and turned flood distribution into an irrigated system to force peasant communities to grow a new crop: cotton. At the turn of the 20th century, cotton went through a major crisis. The two main reasons were salinisation of the irrigated land and the growth of parasites. For nearly a century, irrigation has been done with virtually no artificial drainage network. Following Audebeau’s reports on his experiments on the influence of water tables on the crops (from 1900 to 1920), the State set up an immense open-drainage network. With the completion of the Aswan Dam in 1964, agriculture - increasingly intensified since the 19th century - took a new turn with the practice of twice-annual cropping. Once again, the irrigation planners work fell short in terms of drainage. It was not until the eighties and nineties that drainage became balanced with water input. To understand what could happen in other irrigated parts of the world, the Nile Valley offers some useful lessons on the risks of salinisation.