Paddy Field Characteristics in Water Use: Experience in Asia - Water and Agriculture: Sustainability, Markets and Policies - page 216

flood mitigation functions: mountainous regions of Niigata prefecture, Tone river in
Japan, Mekong river, Chao Phraya river in Thailand
groundwater accumulation and recharge functions: the Shira river basin in Kumamoto
prefecture in Japan
soil erosion and hillside collapse prevention functions
eco-system protection functions: the Kokai river and others in the Tone river basin in
Japan
landscape formation functions, health and recreation functions.
Moreover, he made a review on the methodologies of economic evaluation of the multi-
functional roles of paddy field irrigation such as the substitution method, the contingent
valuation method, the hedonic method, the travel cost method, and the direct method.
Finally, he made a policy proposal to domestic policymakers and the international
community.
On the other hand, the Rural Development Bureau in the Ministry of Agriculture,
Forestry and Fisheries of Japan submitted a proposal document to the OECD Expert
Meeting on Agricultural Water Quality and Water Use Indicators held in Gyeongju, Korea
in October 2003. In the document entitled “The Relationship between Water Use in Paddy
Fields and Positive Externalities —Japanese Perspective and Proposal”, Yamaoka (2003)
describes some examples of attempts to evaluate the multi-functional roles of paddy field
irrigation and drainage, such as:
aquatic creatures in paddy fields in Japan, paddy fields required for breeding of
migratory and endangered birds in Japan;
water returned to the river from paddy fields in the Kino river basin, balance of nitrogen
in paddy and dry fields, effect of reducing peak flood runoff by water storage facilities
for agriculture, provided by Dr. Kato and others, NIRE, Japan;
example of supplying water resources for industrial needs in Youkaichi city, example of
the relation between water use in paddy fields and change in recharging of groundwater
in the Tedori river basin in Ishikawa prefecture in Japan.
2.4. Roles of paddy rice agriculture
The principal grain crop in the Asian monsoon region is rice. Rice supplies 31% of
total food calories to people in Asia while only 3% in other areas in the world. Rice
supplies more than 60% of total food calories in some countries such as Bangladesh,
Cambodia, Laos, Myanmar and Viet Nam. Even in OECD member countries in Asia,
Japanese and Korean people receive 23% and 31% of total food calories from rice
(Table 2).
Surveying the cultivation of the “big three grains” in various regions of the world, we
find that Asia accounts for nearly 90% of the world's paddy rice cultivation area. The
cultivation of wheat, meanwhile, predominates in Europe, Russia, West Asia, and