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COUNTRY
PROFILE - JAPAN
Japan is an island
country in the North Pacific Ocean. It lies off the northeast coast of
mainland Asia and faces the Russia, Korea, and China. Four large islands
and thousands of smaller ones make up Japan. The four major islands -
Hokkaido, Honshu, Kyushu, and Shikoku - form a curve that extends for
about 1,900 kilometres. More than 120 million people are crowded on these
islands, making Japan one of the most densely populated countries in the
world.
The official language
of Japan is Japanese and its geographical area is 377,873 km2. The population
of Japan is 126,926,000 and its irrigated area is about 2,600,000 hectares.
Physiography and
Climate
Japan is a land of
great natural beauty. Mountains and hills cover about 70 per cent of the
country. In fact, the Japanese islands consist of the rugged upper part
of a great mountain range that rises from the floor of the North Pacific
Ocean. Japan lies on an extremely unstable part of the earth's crust.
As a result, the land is constantly shifting. This shifting causes two
of Japan's most striking natural features - earthquakes and volcanoes.
The four main islands, in order of size, are Honshu, Hokkaido, Kyushu,
and Shikoku. Japan's territory also includes Ryukyu and Bonin islands.
Honshu, the Japan's largest island has an area of 227,414 square kilometres.
About 80 per cent of the Japanese people live on Honshu. Hokkaido, the
northernmost of Japan's four major islands, covers 78,073 square kilometres.
It is the country's second largest island but has only about 5 per cent
of Japan's total population. Kyushu, the southernmost of the main islands,
occupies 36,554 square kilometres. After Honshu, Kyushu is Japan's most
heavily populated island, with about 11 per cent of the population. Shikoku,
the smallest of the main Japanese islands, covers 18,256 square kilometres.
About 3 per cent of the Japanese people live on the island. The Ryukyu
and Bonin islands includes Okinawa, the largest and most important island
of the group.
The climate of the
Japanese islands varies considerably from south to north. The southern
islands of Kyushu and Shikoku have a warm temperate climate, much like
the southeastern coastlands of Queens land, Australia, with long hot summers
and mild winters. Honshu has warm, humid summers. Hokkaido, in the north,
with its cool summers and cold, snowy winters, has a climate like that
of southern Sweden. The average annual rainfall of 1700 mm is rather evenly
distributed.
Two Pacific Ocean
currents - the Japan Current and Oyashio
Current - influence
Japanese climate.
Japan is located in
the Asia monsoon area and has one of the highest precipitations in the
world. The annual per capita precipitation is only 5,200 m3/year-person,
or about one-fifth the world annual average of 27,000 m3/year-person.
The potential water resources of Japan are about 420 K m3 for a normal
year and about 280 K m3 for a dry year.
Precipitation data
from 1956 to 1995 shows that the potential water resources in dry years
have declined in these years.
Agriculture
The most important
crop in Japan is rice. Japan is one of the world's leading rice-producing
countries. Rice fields occupy more than 50 per cent of the country's farmland.
Japanese farmers also grow a wide variety of other crops, including sugar
beet, tea, tobacco, and wheat. Mulberry bushes are grown on some hillsides.
Many types of fruits, including apples, mandarin oranges, pear, persimmons,
and strawberries are grown in Japan. Common vegetables grown by Japanese
farmers include aubergines, cabbages, carrots, Chinese cabbages, cucumbers,
onions, potatoes, sweet potatoes, tomatoes, and white radishes.
Agricultural water
Usage
Water use for agriculture
has recently been flat nationwide, with a slight decrease in rice paddy
irrigation offset by an increase in irrigation for other crops.
Irrigation for other
types of crops is expected to continue to increase because the area land
with access to irrigation is increasing and in many cases, agricultural
chemicals and fertilizers are mixed with the water that is used to irrigate
these fields. The supply or water to greenhouses particularly, has increased
steadily in recent years, and their growing popularity has increased the
demand for water in winter. Irrigation channels have traditionally served
several functions in agricultural areas, such as supplying water to wash
crops and agricultural machinery, fire protection and preservation of
the rural environment.
Development of
irrigation technology in Japan
Modern irrigation
systems in Japan were first introduced in the 1950s. The Aichi Irrigation
Project created one of the first modern irrigation facilities that used
automatic checks along the trunk canals for constant, stable water distribution.
Japan has established
irrigation systems based on the open channel type in main and branch lines.
These systems and canals were lined with concrete. The main objectives
being to supply water to paddy fields and to increase rice production.
Water management is carried out by the traditional method based on the
experience of the old irrigation system. A pipeline system also started
in 1960s for upland crops. Pipe lines began to be used as Trunk Lines
for paddy fields from 1970s. Japan, however, considers that the water
resources are limited and irrigation water accounts for around 60 percent
of total water consumption in Japan.
Pipelines introduced
from 1980s for paddy and upland fields replace farm ditches. Farmers are
thus able to irrigate their fields whenever needed, and draw water individually
according to their farming schedule.
A water management
system with telemonitoring and telecontrol has also been introduced. Pipeline
systems and computer based water management systems have recently been
introduced, and some problems remain, especially concerning water control
and management.
Water control system
The traditional systems
are a "supplier-led" water control system, and the farmers are
accustomed to it. Accordingly, modern open channel irrigation systems
have been managed without difficulty.
However, the introduction
of the pipeline system for irrigation produced a radical change in supplier-led
water control system. A benefit of the pipeline system is that farmers
in the system can take as much water as they want. If they open or close
the valve at the end of the system, water will come out or stop. In the
pipeline system users control the water, and thus it is a "user-led"
water control system.
The user-led system
cannot be controlled at the head of the system. Usually, the head of the
pipeline is located comparatively high. The introduction of a pipeline
system requires the water control system to be changed from the traditional
supplier-led one to the user-led one. The water requirement varies mainly
with the rainfall. Frequency of changing water supply to suit the requirement
used to be weekly or seasonally. After introducing a pipeline hourly changes
in water requirement cannot be ignored.
Japan aims to adopt
policies regarding Water Circulation in Catchment Areas by defining the
role of agricultural water use in water circulation system. Agriculture,
forestry and fishery activities are maintained by utilizing the reproductive
power of nature itself, and rely on the natural environment including
the air, water and soil. Industrial activity is also based on the circulation
of natural materials. The rural environment forms the basis of semi-artificial,
semi-natural, or secondary nature, which is formed by humans using nature
continuously for agricultural production. However, to prevent floods,
forests and agricultural lands which account for most of the land use
in catchment areas contribute as follows through sound production activity
by farmers and forestry workers :
- prevent soil erosion
and debris avalanche;
- help the percolation
and storage of precipitation; and
- return most of
the water to rivers eventually.
Use for irrigation
accounts for two thirds of the water requirement, and extensive networks
of irrigation canals have been built that comprise much of the water circulation
system in catchment areas.
In Japan, agriculture,
forestry and fisheries are controlled to stabilize the food supply, to
develop agricultural, forestry and fishery villages, to preserve the land,
and to contribute to the growth of the economy and society. Such management
has, directly and indirectly, supported many functions such as conservation
of the land and environment of forests, farmlands and coastal areas. However,
in line with recent changes in economic and social conditions, catchment
areas have also been changing drastically.
In order to build a sound water circulation system, it is considered that
the ministries and agencies concerned and those living in catchment areas
(irrigators, inhabitants and so on) recognize the role of forests, farm
lands and agricultural activity in the water circulation system.
In Japan, irrigation
has been managed by people in the villages, and farm villages have been
formed under irrigation orders based on rules developed over time. So,
the environment in Japanese traditional farm villages is preserved mainly
by the water users' associations originally established for allocating
agricultural water,. Diversion facilities which were used to allocate
water to tertiary canals in the community and ditches in each field were
managed by each community, and the management was based on the principle
of "communal activity" symbolized by compulsory services, while
water users' associations have managed main headwork and canals, and distributed
water properly to each community. These compulsory services in each community
were not confined to management of water, but covered all things including
management of water for households and farm roads required in the community.
Land Improvement Districts have gathered much know-how about how to manage
the environment in Japanese traditional farm villages. But due to the
critical situation facing agriculture and farm villages including low
prices for agricultural products, urbanization and farmers and non-farmers
living alongside in agricultural and rural communities, depopulation and
aging, Land Improvement Districts are being forced to operate on a weaker
financial basis and less communal function within the community.
Allocation of water
resources in the existing system of the River Act has generally been decided
by the river administrator, Ministry of Construction, for the public interest.
Ministry of Construction is responsible for granting permission to use
irrigation. However, the irrigation situation, including the higher demand
for water for water use per hectare, the trend of repeated water shortages,
and new demand for water for the environment and others, is changing,
and it is also becoming difficult to develop new water resources.
However, Japan considers that coordination of irrigation, that is, allocation
of water resources, cannot be managed centrally and appropriately by the
public river administrator, because it is different from flood control.
Coordination of irrigation is based on coordination among various irrigation
parties. This coordination is result of the self-governing function in
basin areas. Irrigation coordination associations, therefore, are needed
to be established for negotiating and coordinating among all of the water
users (not necessarily for the whole system) who are involved in order
to allocate water properly over a wide area. In doing this, the departments
and agencies for irrigation, and the river administrator should serve
as advisers, and should generally reflect the intentions of water users
summarized by the irrigation coordination association in the management
of agricultural water use and river management. This falls into line with
the demand for minimum involvement by the government (to reduce administration
costs) in recent years.
From the viewpoint
of the water circulation system, hillsides and mountainous regions conserve
the land by preventing soil erosion, floods, as well as cultivate water
resources by forests and farm lands because of their locations. The various
functions of such forests and farmlands protect economic and social activities
in the downstream areas.
Farming of hillsides
and mountainous regions is being abandoned due to aging of people and
depopulation. Because the water circulation system must be secured, it
is necessary to preserve farm lands by taking measures including conserving
terraced paddy fields, preventing the abandonment of agricultural lands,
and managing agricultural lands in uncultivated.
Table
1. Production of Cereals (t)
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2000
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2001
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2002
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2003
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| (1) Cereals,
Total |
12,795,980
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12,254,770
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12,183,860
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10,822,960
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| (2) Cereals (Rice
Milled Eqv) |
8,845,601
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8,485,210
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8,483,897
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7,579,540
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| (3) Cereals other
than rice |
932,980
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934,770
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1,072,860
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1,082,960
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| Rice, Paddy |
11,863,000
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11,320,000
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11,111,000
|
9,74,000
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| Wheat |
688,200
|
699,900
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827,800
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855,200
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| Barley |
214,300
|
206,400
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217,200
|
198,500
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| Maize |
180
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170
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160
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160
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| Oats |
1,500
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2,000
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2,000
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2,000
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| Millet |
300
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300
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300
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300
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| Buckwheat |
28,500
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26,000
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25,400
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26,800
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Source
: FAOSTAT(www.fao.org)
Japan and ICID
Japan joined ICID
in the year 1951 and ever since actively participated in the activities
of ICID.
Japanese National
Committee hosted the 14th IEC meeting and 5th ICID Congress in Tokyo,
in 1963 and 7th Afro-Asian Regional Conference in Tokyo in 1989.
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Mr.
Shinsuke Ota