Producing more food with less water in the dry areas: Challenges and opportunities

摘要

The dry areas are experiencing severe and growing water scarcity.Its impact on food security and the environment,could potentially lead to socio-political instability and conflicts.Agriculture,the largest consumer of water,receives a progressively smaller proportion of total water resources – while food demand continues to rise.It is therefore essential for countries in the dry areas to produce more food with less water.Conventional approaches aim to increase crop yields(increase land productivity)while investing in modern irrigation systems – but this approach has major limitations.Higher crop yields generally require more water,which is hardly available.Modernizing irrigation systems may not result in real and substantial water savings; they increase the field and farm irrigation efficiencies,but not necessarily the overall efficiency at basin or landscape levels.In water-scarce areas,where water is more limiting than land,the focus must shift from land productivity to water productivity,which is the return per unit of water used.Research has shown that it is possible to double water productivity in the dry areas; this is equivalent to doubling available water resources.Water productivity can be increased through improving crop water management and technologies such as deficit irrigation,supplemental irrigation and water harvesting.Simultaneously,countries may cultivate highly water productive crops while importing crops with lower water productivity.However,this will require changes in cropping patterns,irrigation approaches,crop improvement strategies,policies and institutions; and greater investment in research and capacity development.