Wasserproduktivität steigern

Wasserknappheit habe negative Auswirkungen auf das Wachstum in der Lebensmittelproduktion. Deshalb müsse versucht werden, die Wasserproduktivität zu steigern, schreibt Lester R. Brown in einem Kommentar für das Earth Policy Institute am 27. August 2008.

First and foremost, „a new mindset and a new way of thinking about water use“ are needed, says Brown. To this end, he calls for improved irrigation efficiency, which is crucial to improving water productivity. 

This can be done by introducing new irrigation systems that consume less water and manage water more efficiently. In many countries, including India, Mexico, Pakistan, Malaysia and Israel, Brown explains that „water efficiency is affected not only by the type and condition of irrigation systems but also by soil type, temperature and humidity“. 

Hot arid regions are particularly at risk as „the evaporation of irrigation water is far higher than in cooler humid regions,“ says the author. 

For this reason, resolving to move from the current, less efficient flooding technique to other systems like overhead sprinklers or drip irrigation would significantly raise irrigation water efficiency. Drip irrigation systems are said to be „well-suited to countries with a surplus of labour and a shortage of water“ as they are „labour intensive and water-efficient,“ says the paper. 

Only a few countries – Jordan, Cyprus and Israel – have opted to use this system. Water policy analyst Sandra Postel believes drip technologies would irrigate 10 million hectares of India’s land if the system were to be applied on several scales. 

As for water management, the author believes institutional change is necessary, calling for the management of irrigation systems to be left to local water users associations rather than government bodies. „Farmers tend to do a better job than distant government agencies,“ he says. 

Water should be priced „accordingly“ as it is becoming a scarce resource, argues the paper. China exemplifies this case, as its leaders have increased water prices to dissuade people from wasting it. 

He concludes by stating that „reducing water use to the sustainable yield of aquifers and rivers worldwide involves a wide range of measures not only in agriculture but throughout the economy“.