The International Water Management Institute held its annual "Stockholm Water Week" in AUgust 2009 which saw the publication of a report entitled "Revitalizing Asia's Irrigation to Sustainably meet tomorrow's needs".
The report points out that Asia is home to 70% of the world's irrigated land and warns that without major reforms and innovations in the way water is used for agriculture, many developing nations face the politically risky prospect of having to import more than a quarter of the rice, wheat and maize they will need by 2050.
The study was carried out by IWMI and the United Nations Food and Agriculture Organization (FAO) along with researchers from partner organizations with funding from the Asian Development Bank (ADB). It outlines three options for meeting the food needs of Asia's population, which will expand by one and a half billion people over the next 40 years. The first is to import large quantities of cereals from other regions; the second to improve and expand rainfed agriculture; and the third to focus on irrigated farmlands.
To meet expected cereal demand by 2050, IWMI's projections show that, with present trends of yield growth, the area of irrigaged farmland in South Asia would need to increase by 30%, and in East Asia by 47%. Without water productivity gains South Asia would need 57% more water for irrigated agriculture and East Asia 70 % more. Given the existing scarcity of land and water, and growing water needs of cities, such a scenario is untenable. This clearly points to a need for dramatic increases in water productivity, which can only be achieved with a complete revitalization of irrigation infrastructure, management and policy.
The scenarios presented in the IWMI-FAO report do not factor in climate change, which will likely make rainfall more erratic and increase the strain on already overstretched irrigation systems.
The report finds that the potential for improvement is particularly great in South Asia, where more than half of the harvested area is irrigated yet yields are low. Asia as a whole could obtain as much as three-quarters of the additional food it will need by improving the performance of irrigated crop production, and South Asia could satisfy all of its additional demand.
Another option is to shift more land to rainfed farming but the scope is found to be limited - in South Asia 94% of the land suitable for farming is already in production. As a consequence, significant expansion of rainfed farming would come largely at the expense of fragile marginal areas with high environmental costs in terms of biodiversity loss and greenhouse gas emissions.
The report therefore proposes an alternative strategy, the key element being to modernize the region's large-scale irrigation systems, which were built to rely on surface water. Another critical measure is to selectively support rather than thwart the trend toward individual farmers' use of inexpensive pumps to extract groundwater for irrigation. In India, an estimated 19 million such pumps are providing water for more than 60% of the nation's total irrigated area. Instead of condemning this widespread practice, governments should actively support innovative initiatives. A third component of the IWMI-FAO strategy is to involve the private sector more actively in publicly managed irrigation systems.
The report is attached below.
For more about the IWMI, see here.
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