Technologies in irrigated agriculture: costs and benefits

Asian region has not only the highest share (70%) of the world irrigated area, but also has the largest proportion (60%) of world's population to feed. Credible forecasts suggest that in coming decades most of the expansion of world irrigated area will takes place in Asia. Today, Asian irrigated agriculture is facing the triple challenge of water resource development, irrigation area expansion with least environmental impacts, and increasing food production with progressively diminishing water supplies. Improved technologies and tools play a significant role in achieving water savings, better operation and maintenance, and overall gains in irrigation performance and thereby in food production.

There is a vast range of technologies available for improved operation, better management and efficient use of irrigation water -ranging from simple siphon tubes for field water application to sophisticated canal automation and telemetry. These technologies and tools available can be clubbed under three categories viz., off-farm technologies, on-farm technologies, and Soft tools in respect of both on- farm and off-farms.

The off-farm technologies provides improved operation, regulation, flow control and distribution in conveying and delivering irrigation water from the source to fields at the desired flow rate, at pre decided time and locations in the command area with minimum losses. These technologies include canal lining with conventional as well geo-synthetic/geo-membrane materials, SCADA, improved flow measuring and regulating devices, the use of telemetry, modern water delivery outlets, introduction of farm ponds and storage on farm etc.

On-farm technologies comprise all those field water application methods which apply irrigation water to crops as precisely as possible. Improved gravity methods on laser levelled fields, modern pressurized irrigation methods like low pressure center pivot and linear move sprinkler systems, subsurface drip, and micro sprinkler systems have dramatically changed the way crops had been traditionally irrigated. Now it is possible to apply water and other inputs like fertilizers/nutrients, pesticides to crops quite precisely and at the desired time and quantities. Availability of both simple and sophisticated tools for irrigation scheduling has further enabled achieving high crop and water productivity. Beside the advances in the hard technologies at the off-farm and on-farm scale, soft tools like canal operation simulation models, decision support systems, benchmarking, stock management, FAO's RAP, MASSCOTE, have greatly facilitated improved operation, maintenance, monitoring and evaluation of irrigation systems.

Despite availability of a wide spectrum of irrigation technologies, there are technical, economic, social and institutional issues in adoption of these in Asian region on wide scale. The paper highlights some strategies and recommendations to fully explore the potential benefits of these technologies in irrigated agriculture of Asia. This includes developing appropriate and affordable technologies and their effective dissemination, capacity development and training of irrigation managers, field staff and farmers, enhancing investment/funding by national governments, private sectors, and international financing institutions.

Since last six decades International Commission on Irrigation and Drainage (ICID) has been active in promoting ‘managing water for sustainable agriculture’ across the world. The Commission has made significant contributions in promoting irrigation technology and water saving initiatives in close collaboration with its member countries, experts, and other stakeholders. ICID had looked into some of the non technological aspects that impact water savings including water pricing, Policies and Agricultural Markets etc and their positions are also covered.