Improving Water Use Efficiency in Asian Agriculture
More crop for every drop
Enhanced Irrigation and Water Use Efficiency
One of the sources of future growth in crop production in the region is enhanced efficiency of irrigation and water use. During the next 30 years, the expansion of irrigation in the developing countries will drop to only 0.6 percent annually. This will be affected by the increasing cost of bringing additional areas under irrigation, as well as the growing scarcity of water resources. However, due to the increase in cropping intensity under irrigation, the harvested irrigated area in the next 30 years will increase by 86 million hectares. Most of this gain will take place in Asia, where irrigated land will reach about 40 percent of total arable land.
According to the Food and Agriculture Organization (FAO), to meet the multiple demands in irrigation and water use, agriculture policies will need to unlock the potential of water management practices to raise productivity, promote equitable access to water, and conserve the resource base. It proposes a strategy to "re-invent" water management in the agriculture sector, based on modernization of irrigation infrastructure and institutions, the full participation of water users in the distribution of costs and benefits, and the revival of flagging investment in key areas of the agricultural production chain.
It is under this premise that FFTC, together with IWMI and the Philippine Council for Agriculture, Forestry and Natural Resources Research and Development (PCARRD), organized the International Workshop on Enhancing Water Use Efficiency through Improved Irrigation Management Technologies in December 2003. Through the workshop, the Center hoped to promote far-reaching irrigation and water use reforms in the region that are likely to tremendously affect not only the farmers, but the public in general. The workshop was based on the notion that technological advances together with innovative participatory approaches and appropriate policies and support services, are vital in ensuring the efficiency of irrigation and water use in the Asian region to enable agriculture to respond to changing patterns of demand for food, combat food insecurity and poverty, and compete for scarce water with other users.
Improved Irrigation Management Practices
Different Asian countries are carrying out a range of programs to improve their use of irrigation water. In Korea, for instance, fertigation is practiced as a method of enhancing the efficiency of water use and fertilizer application. Irrigation efficiency through fertigation is measured using hardware and software management tools. The recently developed Korean auto-irrigation system covers a number of plots, and can irrigate several plots at the same time. It uses an electronic tensiometer to measure the level of soil moisture, and an electric flow meter as a watering gauge. This system provides accurate and uniform applications of water and fertilizer at a low labor cost.
Japan taps its biggest river in Kyushu island, the Chikugo river, for irrigating diversified cropping systems through water re-use and recycling. This is made possible through the canal-reservoir network systems that can be found in the river's downstream portion. In these lowland areas, water demand for irrigation is higher than the potential water supply because of the river's relatively small basin. Farmers also practice the Ao-intake method as a means of maximizing the amount of stored water. During high tide, water pours in through the intake gate. Use of available water is maximized by a massive system of pipelines and pumps, as well as open canals.
In Malaysia, water recycling based on water loss from irrigation system is practiced to contribute towards improving irrigation efficiency. In 1982, an irrigation recycling pump project was launched with a conservative estimate of 0.2 m of water availability from the paddy areas. This is equivalent to about 193 million m3 of water. Currently, approximately 110 million m3 of water is being recycled annually in the area. Full potential of recycling has yet to be exploited. New sites suitable for recycling pump stations have been identified for future development.
A common practice now in the Philippines is the pressurized irrigation system (PIS), which uses drip and sprinkler systems. More than 21,600 hectares are now irrigated in this way, mainly in Mindanao, much of which is planted in high-value crops such as banana and mango. PIS reduces non-beneficial evaporation, applies water uniformly to crops, reduces stress in plants, and helps increase the economic productivity of water. PIS is appropriate in high-value production and other intensive cultivation.
Irrigation systems for rice paddies depend partly on the scale of production. Paddy farms in Taiwan, Korea, and Japan are fairly small. However, irrigation and drainage practices are sophisticated, and considerable labor is needed to control the gate operations. This becomes economically inefficient when labor costs are high. Rather than independent management of irrigation water by farmers, the focus now is on rotational block irrigation, with ditches to recycle the overflow. This system helps reduce labor costs, and promotes the use of mechanization.
The Role of Policy, Institutions, and Farmers' Participation
The problems identified during the presentations and discussions can be categorized into technical, economic, institutional, social and political, and environmental.
Some technologies that have been developed are not acceptable under local conditions. This is because of several factors, including a lack of funds for large infrastructure projects, lack of technical skills to automate irrigation systems, and lack of adequate rainfall as one source of irrigation water. In developed countries, where funding is less of a problem, the issues related to the costs and benefits of large infrastructure projects are still under discussion. When governments make a large capital investment, there may be less concern to assess its cost effectiveness.
Common among developing countries with small farms is the problem of collecting irrigation service fees. Most, if not all, experience a low rate of payment of fees. This low rate of collection leads to another problem, of poor infrastructure and irrigation facilities due to lack of funds. This in turn reduces the productivity of farms.
The impact of intensive agriculture on the environment was another concern for almost all countries represented at the workshop. The growing public awareness of the deteriorating water quality and widespread water pollution makes it imperative to develop a more holistic approach to water resources management.
It seems that the key success factors in irrigation management are related and intertwined. The absence or weakness of one factor leads to the inability of the whole system to perform at its best. Among these factors are: availability and appropriateness of technologies; management
approaches and systems; facilities and infrastructure development; government and policy support; provision of incentives and availability of financial support; and improvements in the institutional and organizational structures, functions, and operations.
Where there is an integrated, holistic approach to irrigation management, the impacts are positive. Water use efficiency involves a wide range of factors such as farm size, soil conditions, cropping patterns, agronomic crops, as well as the interplay of socio-political and economic aspects of allocation, management, and utilization of water.
In this workshop, farmers' participation in the planning, implementation, monitoring, and evaluation of irrigation projects was given emphasis. Also, a well-organized water users' group or irrigation association must be in place to enable members to undertake operations and maintenance.
Increasing water use efficiency in agriculture is necessary to solve many of the problems of the water crisis, but this alone is not sufficient. Considerable attention must be given to establishing and maintaining access to water for domestic uses and income generation, affordable water-productivity enhancing technologies, and giving the small-scale farmers a voice in water decisions.
Index of Images
Figure 1 Water Resources Development Facilities in Japan
Figure 2 Irrigation Canal in Korea
Figure 3 Water Recycling in Malaysia
