Mr. Thierry Facon highlighted the importance of water in sustainable rice production. Despite the constraints of water scarcity, rice production must rise dramatically over the next decades. Producing more rice with less water is therefore a formidable challenge for food, economic, social and water security of the region.
Asia is relatively well endowed with water resources, but water resources per inhabitant are only slightly above half of the worlds average. Countries like India and China are approaching the limit of water scarcity. About 84% of water withdrawal is for agriculture, with major emphasis on flooded rice irrigation. There has been a rapid increase in irrigation development. Most countries have achieved self-sufficiency in rice. Schemes are designed primarily to secure rice cultivation in the main cropping season. Some countries design new irrigation schemes for year-round irrigation. Rice represents about 45% of irrigated areas and 59% of the rice land is irrigated. Average cropping intensity is 127%. The 28 million hectares under intense irrigation producing two to three crops per year suffer from declining productivity. Growth in irrigated areas has declined in recent years. Groundwater draw-down has reached alarming levels in many areas. Declining prices of rice, higher marginal development costs, environmental concerns, and poor performance of existing schemes are among the main factors of the decline in irrigation growth and investment both by governments and farmers. Increased competition for water between sectors already affects agriculture. Poor operation and maintenance of large public schemes has led to irrigation management transfer or increased participation of users through water users associations. Socio-economic changes and water scarcity call for a transformation of irrigation by the adoption of measures to modify water demands and maximize efficiency in water use, to improve its economic, technical, and environmental performance, together with diversification of produce and cropping patterns, changes in management systems and structures, financial and fiscal sustainability. But rehabilitation programmes are assuming increasing importance. Progress in modernization is slow when compared with other regions.
Scenarios for growth in water demand suggest that because of the projected increases in food demand, irrigated food production will need to increase significantly. Demand from other sectors will also increase because of economic development and increase in population. Nearly all countries in the region will need to invest considerable efforts and resources in a mixture of improved demand management of the water sector and interventions on the supply side to achieve the very considerable improvements in water use which are required. But approximately 1 billion people would live in regions of absolute water scarcity.
There is a need to improve rice water productivity as well as water use efficiency. Land preparation, soaking for maintaining water level in the paddy fields and soil saturation require more water than plant transpiration. System and farm irrigation is quite low (in the range of 30 to 40%). A river basin perspective should be adopted, defining the boundaries of intervention (farm, system, basin), paying attention to managing the return flows and to water quality. However, practices which minimise irrigation inflow are of a direct interest to farmers who receive less and more costly water. Water saving practices, which require greater water control, typically are associated with or part of packages to improve agronomic practices and the efficiency of use of other inputs. Available strategies include developing improved varieties, improving agronomic management, changing the crop planting date, reducing water use for land preparation, changing rice planting practices with wet or dry seeding, reducing water use during crop growth through intermittent flooding, maintaining the soil in sub-saturated condition, alternate drying and wetting, optimum use of rainfall, supplementary irrigation of rainfed low-land rice, water distribution strategies, water recycling and conjunctive use and alternative methods to flooding for growing irrigated rice under aerobic conditions.
Acceptance by farmers of these strategies and practices will depend on economic factors, improved water control and management of water at the system level for a better irrigation and drainage service and a conducive environment i.e. legal framework at national and local levels. Technical support in upgrading irrigation systems for efficient water distribution, and agricultural support in adapting agricultural practices to modified irrigation methods, will be equally important. Financial support to initiate community-managed credit-schemes, human resources development at district and community level, and a facilitating environment (market systems, storage facilities, management of agricultural produce and sound government macro-economic policies) to permit increases in production will ensure the economic viability of projects.
Improvements in the Operation and Maintenance (O&M) of rice irrigation schemes through rehabilitation of the deteriorated systems, irrigation infrastructure improvement for surface irrigation, irrigation management transfer, modernization, combining to various degrees institutional, organizational and technical changes, have been attempted in the region with mitigated degrees of success. A recent evaluation suggested that the more reticulated systems, capable of supporting on-demand water delivery, were not appropriate under humid climates. A second study found that irrigation projects were performing poorly, that operation and maintenance were better than expected and that there was no substantial negative constraints on irrigated production attributable to poor performance in O&M. Projects offered poor economics and low incomes. Recommendations were to sharpen the response to O&M failures, simplify infrastructure and operations, promote management transfer to farmers judiciously and improve household earnings by diversifying cropping systems and supporting research, extension and marketing for speciality crops and integrated high-value farming. Modernization projects were also evaluated recently. Most field (on-farm) irrigation methods in these irrigation projects were relatively simple, the initial focus on modernization was generally on reliability and equity and flexibility and control will be more important than they are at present. Water User Associations (WUAs) provide distinct advantages if they are properly empowered. WUAs that hire staff to distribute water and run the water distribution similar to a business operation are often quite strong. The desired service that will be provided at all levels within the system and the strategy combining hardware and management improvements must be clearly defined. The vision for all modernization programs must be on the water delivery service that is needed 30 years from now. Present project designs are not capable of supporting economically and technically the intensified, diversified and more water efficient production systems of the future. Modernization or improvement efforts have been inappropriate and poorly adapted to circumstances and rice-based production systems remain incomplete. Programs for improved irrigation scheduling for field irrigation will fail unless the water delivery service is well controlled, reliable and flexible. The design logic of systems in large parts of India and Pakistan clearly will not allow farmers to adopt the improved water saving technologies and management practices for rice production. A revolution in irrigated agriculture focusing on improving the performance of existing irrigation facilities and provision of a client-focused irrigation service is required.
Considerable investments in economic as well as human resources will also be required. Appropriate strategies will have to be designed carefully with the involvement of the farmers, but will need to be resolutely forward-looking and perhaps revolutionary.