(GIAHS) was introduced. Furthermore, examples of
agricultural production and soil environment conservation
were introduced.
Keywords
Geography and geology Á Climate condition Á Andosols
Á Anthropogenic soils Á Agricultural production and soil
properties Á GIAHS
7.1 Outline of the Kanto-Koushinetsu
Region
7.1.1 Perspective of the Kanto-Koushinetsu
Region
Kanto-Koushinetsu is a geological area shared between the
island of Honshu and other nearby islands (Fig. 7.1). The
area has an extremely large population (more than 48 million) and large amounts of industry and includes the Tokyo
metropolis and the prefectures of Ibaraki, Tochigi, Gunma,
Saitama, Chiba, Kanagawa, Yamanashi, Nagano, and Niigata. The Kanto-Koushinetsu region is usually divided into
three sub-regions: (1) the Kanto region, which includes the
Tokyo metropolis and the prefectures of Ibaraki, Tochigi,
Gunma, Saitama, Chiba, and Kanagawa; (2) the Koushin
region, which includes Yamanashi and Nagano Prefectures;
and (3) Echigo, which includes Niigata Prefecture. In general, the Koushin region and Echigo are together referred to
as “Koushinetsu.”
A total of 40% of the Kanto region consist of mountainous areas, which is lower than the national average
(61%). The region also contains the Kanto Plain, the largest
plain in Japan. The proportion of cultivated land in the
Kanto region (18.6%) is higher than the national average
(11.5%), due to agricultural activities on the region’s wide
flat areas, such as the Kanto Plain, that are suitable for
cultivation. Highly profitable urban agriculture, such as
vegetable production, is conducted while taking advantage
of proximity to big cities. In contrast, however, the distribution of paddy fields in the Kanto region is lower than the
Japanese average.
The Koushin region is characterized by high mountainous
areas. The average land altitude in Japan is 378 m above sea
level (a.s.l.), but in Nagano and Yamanashi Prefectures, the
averages are 1033 m and 913 m a.s.l., respectively; these
prefectural averages are the highest and the second highest in
Japan. Furthermore, the top five highest mountains in Japan
(Mt. Fuji, Mt. Kita, Mt. Okuhodaka, Mt. Mano, and Mt.
Yarigatake) are located in these prefectures. Moreover, the
area ratio of mountains in Nagano Prefecture (86%) and
Yamanashi Prefecture (85%) is much higher than the
national average. These two prefectures have unique geological conditions and are famous for their fruit and highland
farming. Yamanashi Prefecture produces the largest amount
of grapes and peaches of all Japanese prefectures, while
Nagano Prefecture produces the largest amount of highland
lettuce and the second largest amount apples.
Niigata Prefecture is located in the northern part of the
Kanto-Koushinetsu region and is the only prefecture in the
region that faces the Sea of Japan. The Echigo Mountains are
located in the south of Niigata Prefecture and divide the
prefecture from the Kanto region. The Echigo Mountains are
known to receive among the heaviest snowfall of any area in
the world, with an average snow depth of 3 to 4 meters. As a
result of this large snowfall, the mountains are the source of
several rivers, which flow into the Sea of Japan. In the lower
reaches of these rivers, the Echigo Plain extends to the
coastal area of Niigata Prefecture. This plain is the fourth
largest in Japan, and is also the largest rice production area,
using the abundant supply of snowmelt from the Echigo
Mountains to irrigate rice paddy.
7.1.2 Geography and Geology
of the Kanto-Koushinetsu Region
(1) Geography and geology of the Kanto region
The Kanto region has the largest plain in Japan (the Kanto
Plain, with an area of about 17,000 km
2 ). This plain is
bordered by 10 active volcanoes (Mt. Nasutake, Mt. Takahara, Mt. Nikko-Shirane, Mt. Nikko-Nantai, Mt. Akagi, Mt.
Haruna, Mt. Kusatsu-Shirane, Mt. Asama, Mt. Fuji, and Mt.
Hakone) located in the north and southwest of the region, by
the Kanto Mountains in the west, and by the Pacific Ocean to
the south and east (Fig. 7.1). Large quantities of tephra from
the surrounding volcanoes—Mt. Asama, Mt. Haruna, and
Mt. Akagi to the north and Mt. Hakone and Mt. Fuji to the
south—have been deposited on the Pleistocene terraces of
the Kanto region, thereby maintaining the Kanto Plain as the
largest plain in Japan. The Pleistocene terraces in this region
are the most important geomorphological plains in Japan
from an agricultural and pedological viewpoint, because
Andosols (which are mainly used for upland crops) are
widely distributed on these plains (see Sect. 7.1.3).
The Kanto Mountains consist of three major tectonic belts:
the Sambagawa belt, in the north, and the Chichibu and Shimanto belts, in the south. The Sambagawa belt is constituted
chiefly of crystalline schist that is composed largely of quartz,
graphite, piedmontite, and stilpnomelane. This schist is
thought to have been originally formed from Jurassic to Cretaceous accretionary deposits. The Chichibu belt consists
mainly of mélanges of pelagic, hemipelagic, and trench-fill
246
H. Sumida et al.
agricultural production and soil environment conservation
were introduced.
Keywords
Geography and geology Á Climate condition Á Andosols
Á Anthropogenic soils Á Agricultural production and soil
properties Á GIAHS
7.1 Outline of the Kanto-Koushinetsu
Region
7.1.1 Perspective of the Kanto-Koushinetsu
Region
Kanto-Koushinetsu is a geological area shared between the
island of Honshu and other nearby islands (Fig. 7.1). The
area has an extremely large population (more than 48 million) and large amounts of industry and includes the Tokyo
metropolis and the prefectures of Ibaraki, Tochigi, Gunma,
Saitama, Chiba, Kanagawa, Yamanashi, Nagano, and Niigata. The Kanto-Koushinetsu region is usually divided into
three sub-regions: (1) the Kanto region, which includes the
Tokyo metropolis and the prefectures of Ibaraki, Tochigi,
Gunma, Saitama, Chiba, and Kanagawa; (2) the Koushin
region, which includes Yamanashi and Nagano Prefectures;
and (3) Echigo, which includes Niigata Prefecture. In general, the Koushin region and Echigo are together referred to
as “Koushinetsu.”
A total of 40% of the Kanto region consist of mountainous areas, which is lower than the national average
(61%). The region also contains the Kanto Plain, the largest
plain in Japan. The proportion of cultivated land in the
Kanto region (18.6%) is higher than the national average
(11.5%), due to agricultural activities on the region’s wide
flat areas, such as the Kanto Plain, that are suitable for
cultivation. Highly profitable urban agriculture, such as
vegetable production, is conducted while taking advantage
of proximity to big cities. In contrast, however, the distribution of paddy fields in the Kanto region is lower than the
Japanese average.
The Koushin region is characterized by high mountainous
areas. The average land altitude in Japan is 378 m above sea
level (a.s.l.), but in Nagano and Yamanashi Prefectures, the
averages are 1033 m and 913 m a.s.l., respectively; these
prefectural averages are the highest and the second highest in
Japan. Furthermore, the top five highest mountains in Japan
(Mt. Fuji, Mt. Kita, Mt. Okuhodaka, Mt. Mano, and Mt.
Yarigatake) are located in these prefectures. Moreover, the
area ratio of mountains in Nagano Prefecture (86%) and
Yamanashi Prefecture (85%) is much higher than the
national average. These two prefectures have unique geological conditions and are famous for their fruit and highland
farming. Yamanashi Prefecture produces the largest amount
of grapes and peaches of all Japanese prefectures, while
Nagano Prefecture produces the largest amount of highland
lettuce and the second largest amount apples.
Niigata Prefecture is located in the northern part of the
Kanto-Koushinetsu region and is the only prefecture in the
region that faces the Sea of Japan. The Echigo Mountains are
located in the south of Niigata Prefecture and divide the
prefecture from the Kanto region. The Echigo Mountains are
known to receive among the heaviest snowfall of any area in
the world, with an average snow depth of 3 to 4 meters. As a
result of this large snowfall, the mountains are the source of
several rivers, which flow into the Sea of Japan. In the lower
reaches of these rivers, the Echigo Plain extends to the
coastal area of Niigata Prefecture. This plain is the fourth
largest in Japan, and is also the largest rice production area,
using the abundant supply of snowmelt from the Echigo
Mountains to irrigate rice paddy.
7.1.2 Geography and Geology
of the Kanto-Koushinetsu Region
(1) Geography and geology of the Kanto region
The Kanto region has the largest plain in Japan (the Kanto
Plain, with an area of about 17,000 km
2 ). This plain is
bordered by 10 active volcanoes (Mt. Nasutake, Mt. Takahara, Mt. Nikko-Shirane, Mt. Nikko-Nantai, Mt. Akagi, Mt.
Haruna, Mt. Kusatsu-Shirane, Mt. Asama, Mt. Fuji, and Mt.
Hakone) located in the north and southwest of the region, by
the Kanto Mountains in the west, and by the Pacific Ocean to
the south and east (Fig. 7.1). Large quantities of tephra from
the surrounding volcanoes—Mt. Asama, Mt. Haruna, and
Mt. Akagi to the north and Mt. Hakone and Mt. Fuji to the
south—have been deposited on the Pleistocene terraces of
the Kanto region, thereby maintaining the Kanto Plain as the
largest plain in Japan. The Pleistocene terraces in this region
are the most important geomorphological plains in Japan
from an agricultural and pedological viewpoint, because
Andosols (which are mainly used for upland crops) are
widely distributed on these plains (see Sect. 7.1.3).
The Kanto Mountains consist of three major tectonic belts:
the Sambagawa belt, in the north, and the Chichibu and Shimanto belts, in the south. The Sambagawa belt is constituted
chiefly of crystalline schist that is composed largely of quartz,
graphite, piedmontite, and stilpnomelane. This schist is
thought to have been originally formed from Jurassic to Cretaceous accretionary deposits. The Chichibu belt consists
mainly of mélanges of pelagic, hemipelagic, and trench-fill
246
H. Sumida et al.