-La plupart de l’eau prélevée va à l’irrigation

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Temps de lecture : 2 minutes  

irrigation premeir poste depense eau

On a global scale, agriculture absorbs 70% of all freshwater supplies, a figure that rises to 95% in some developing countries. Irrigation allows food production to be increased, combating hunger and improving living standards. However, irrigation is not without drawbacks. It uses up a resource that is only available in limited quantities: since 1950, irrigated areas have doubled, while the use of water for agricultural, domestic, and industrial purposes has more than tripled. Two examples illustrate the problems of large-scale reliance on irrigation.

Egypt and its 82 million inhabitants are totally dependent on the water provided by the Nile: 100% of agricultural land is irrigated and 96% of this with river water. Thanks to the Aswan Dam, irrigation has been ensured, but salinization—a consequence of intense irrigation in areas where evaporation is high—is now threatening the soil and reducing crop yields.

In Central Asia, the diversion of the Syr-Daria and Amu Darya rivers to allow large-scale irrigation of cultivated areas—predominantly for growing cotton—has resulted in the shrinking of the Aral Sea, which since the 1960s has lost 60% of its surface area and 80% of its volume of water. Its ecosystem has been destroyed, and the local fishing industry has collapsed. Salts and pesticides that have accumulated on the dried sea bed are blown by the wind and are contaminating drinking water supplies, endangering the health of the region’s population.

Is there any way to reduce water consumption and protect freshwater ecosystems while still increasing agricultural production? In regions where rainfall is insufficient or barely sufficient, drip irrigation or micro-irrigation is a method that delivers water directly to the roots of plants through a system of pipes and small sprinklers, reducing evaporation, deep drainage, and contamination. Drip irrigation can create a saving of 40—60% of water compared to traditional systems. Despite the set-up costs, the United Nations Food and Agriculture Organization supports the promotion of this technique in developing countries.

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