Irrigation Revisited

Asia urgently needs to learn how to use water more wisely to feed the additional 1.5 billion people who will live there by 2050, warns a new report.

The report shows that there is scope for doubling the agricultural productivity of Asia's irrigated lands through sustained effort.

A comprehensive new study of irrigation in Asia warns that, without major reform and innovation in the way water is used for agriculture, many developing nations will face the politically risky prospect of having to import more than a quarter of the rice, wheat and maize they need to feed their growing populations. The International Water Management Institute (IWMI) and the Food and Agriculture Organization of the United Nations (FAO) recently released the report during 2009 World Water Week in Stockholm, attracting widespread media attention. Irrigation will play a key role in producing food to feed the 1.5 billion additional people who will live in Asia by 2050. This is the main finding of the report, titled Revitalizing Asia’s Irrigation: To Sustainably Meet Tomorrow’s Food Needs.

The authors use numerical modeling to assess the options Asian states can use to meet future food requirements. The report outlines three such options: 1) import large quantities of cereals from other regions, 2) improve and expand rainfed agriculture, and 3) focus on improving yields from irrigated farmlands.

IWMI director general Colin Chartres says, “Of the three options, the best bet for Asia is to revitalize its vast irrigation systems, which account for 70% of all irrigated land in the world. Relying on trade to meet much of the future food demand would only impose a huge and politically untenable burden on the economies of many developing countries, and rainfed farming is far too uncertain, given climate change predictions.”

Compiled by lead authors Aditi Mukherji of IWMI and Thierry Facon of FAO and funded by the Asian Development Bank, the report draws on the work of over 700 leading experts, in-depth research and computer-based forecasting models.
 
Asian agriculture registered dramatic advances during the 1960s and 1970s through a combination of irrigation, improved crop varieties and fertilizers. The resulting Green Revolution made it possible to avert widespread hunger and raise living standards. From 1970 to 1995, the area under irrigation in Asia more than doubled, making it the world’s most irrigated continent.

However, this extensive irrigation infrastructure is not currently used to its full potential, because the conditions that prevailed when it was built no longer exist. In the 1960s and 1970s, farmers mostly grew cereals such as rice and wheat. They relied on large, centrally managed, supply-driven irrigation schemes to provide water and secure their livelihoods. Today, however, many have diversified to grow more fruit and vegetables in response to changing markets. Such farming methods need more flexible and responsive management that delivers water on demand.

In large parts of Asia, cereal crops will remain dominant. The current state of surface irrigation infrastructure provides suboptimal service, even in large cereal-based systems; hence the need for drastic reforms.

With yesteryear’s large, outdated irrigation schemes unable to meet needs, farmers have installed millions of groundwater pumps across Asia to secure their own supplies. Since there is little regulation of groundwater extraction, water tables have dropped dramatically enough in some places to disrupt surface water flows and the habitats they support. Meanwhile, the old combination of large irrigation developments, mono-cropping and heavy fertilizer use continues to take a toll on the environment. The uncertainties of climate change and its effect on rainfall and runoff complicate the question of how best to ensure food security in Asia while conserving natural resources.

The authors suggest that Asia needs to employ not one but several strategies for improving irrigation to achieve food goals under the varying economic, political and geographic conditions across the continent. They put forward five strategies for helping irrigation perform to its full potential and satisfy future food needs while safeguarding the environment:

1. reengineer large irrigation schemes to meet modern farming needs,
2. emulate farmers’ initiatives where they have successfully employed their own irrigation methods,
3. improve on existing reforms by engaging the private sector in irrigation,
4. boost knowledge through training, and
5. invest in other sectors that indirectly influence irrigation.

Investments in irrigation are closely linked to food and energy prices. The authors note that, with food and energy costs forecast to rise in future, there is renewed interest in investing in irrigated agriculture. However, they warn that reversing the degradation that has resulted from years of neglect calls for innovative methods. The report shows that there is scope to double the productivity of irrigated lands in Asia. To achieve this, farmers need more reliable irrigation systems that provide good service, help in improving soil health and improved crop varieties that resist pests. Only then can they ensure that Asia’s future population does not go hungry.

Revitalizing Asia’s Irrigation: To sustainably meet tomorrow’s food needs is available at www.iwmi.org/SWW2009/ and www.waterknowledgehub.iwmi.org.