sures has been also accomplished to reduce greenhouse
gas emissions and leaching of nitrate, and harmful
chemical substances are also discussed.
Keywords
Brown Forest soils Á Environmentally friendly
agriculture Á Fluvic soils Á Lake Biwa Á Paddy fields
9.1 Outline of the Kinki, Chugoku,
and Shikoku Regions
9.1.1 Perspective and Historical Background
The Kinki, Chugoku, and Shikoku regions are located in the
west-central part of Honshu Island, Shikoku Island, and
surrounding islands, and extend from roughly 32.7–35.8° N
latitude and 130.9–136.5° E longitude. The Kinki region is
administratively composed of six prefectures—Osaka,
Kyoto, Hyogo, Nara, Shiga, and Wakayama—with a total
area of 27.3 Â 10
3 km
2 (corresponding to 7.2% of the area of
Japan) and a total population of 20.68 million people (corresponding to 16.3% of the population of Japan; Ministry of
Internal Affairs and Communications, 2016). The Chugoku
region is administratively composed of five prefectures—
Tottori, Shimane, Okayama, Hiroshima, and Yamaguchi—
with a total area of 31.9 Â 10
3 km
2 (corresponding to 8.4%
of the area of Japan) and a total population of 7.41 million
people (corresponding to 5.8% of the population of Japan
2016). The Shikoku region is administratively composed of
four prefectures—Tokushima, Kagawa, Ehime, and Kochi—
with a total area of 18.3 Â 10
3 km
2 (corresponding to 4.8%
of the area of Japan) and a total population of 3.82 million
people (corresponding to 3.0% of the population of Japan,
2016). The three regions therefore have a combined area of
77.5 Â 10
3 km
2 (corresponding to 20.4% of the area of
Japan) and a combined population of 31.91 million people
(corresponding to 25.1% of the population of Japan 2016).
One of the characteristics of the Kinki, Chugoku, and
Shikoku regions is the early acceptance of the culture of the
Asian continent due to their proximity. Specifically, rice
farming was first introduced from China to Japan (northern
Kyushu) at the later stage of the Jomon period (fourth century BC), as evidenced by the Itatsuki ruins in Fukuoka
Prefecture and the Nahata ruins in Saga Prefecture. Rice
farming was quickly transferred to Eastern Japan and arrived
in northern Honshu at the early stage of the Yayoi period
(fourth century BC to the middle of the third century AD), as
evidenced by the Sunazawa ruins in Aomori Prefecture.
Accordingly, it is reasonable to assume that rice farming was
introduced in the Kinki, Chugoku, and Shikoku regions at a
relatively early stage of the Yayoi period. This would be
partly due to their climatic conditions, which are characterized by relatively warm temperature and plentiful precipitation, and to their geography, which consists of many rivers
and alluvial plains. Additionally, the pedological conditions
of these regions could be another reason for the early
introduction of rice farming; specifically, the distribution of
volcanic soils (Andosols) with high water permeability was
extraordinary sparse and such conditions made it easy to
prepare paddy fields, which require the storage of water for
rice production. In this sense, these regions must have
played a pioneering role during the nascent stage of rice
production in Japan.
Another characteristic of the Kinki, Chugoku, and Shikoku regions is their early development as centers of politics, economy, and culture, from (1) the Izumo Dynasty in
Shimane Prefecture and (2) the Yamato Dynasty in Nara
Prefecture, which named itself “the country of ripening rice”
and introduced an ancient land subdivision system, that is,
the strip system, and a system of periodic reallocation of
paddy fields to farmers, that is, “Handen-shuju-sei” (AD
652), for their governance, to (3) the capital of Heijo-kyo in
Nara Prefecture (AD 710) and 4) the capital of Heian-kyo in
Kyoto Prefecture (AD 794). It is highly probable that the
political, economic, and cultural importance of these three
regions was also strongly influenced by the specific conditions of these regions, including soil distributions.
The third characteristic of the Kinki, Chugoku, and Shikoku regions is their wide variety of population density,
from the second biggest metropolitan and economic center in
Japan (around Osaka; the biggest is in the Kanto region,
around Tokyo) to largely depopulated areas in some parts of
these regions. This variety affects the present land use and
soil management, including for agriculture and forestry.
9.1.2 Geomorphology
The landforms of these regions are classified into mountains
of the “inner zone” (north of the Median Tectonic Line
[MTL]), mountains of the “outer zone” (south of the MTL),
and in-between lowlands ranging from the Seto Inland Sea
to the Kinki triangle zone (Okada and Chinzei 2004).
Distinctive landform divisions in these regions are shown in
Fig. 9.1.
Mountains in the inner zone consist of the Tanba
mountains (1) in Fig. 9.1) in the north of Kyoto Prefecture
and the Chugoku mountains (2), which cover most of the
Chugoku region. In this zone, mountains higher than
1000 m above sea level (a.s.l.) are rare and the average
elevation is 800–900 m a.s.l. The relief of these mountains is
mostly gentle. The Chugoku mountains include backbone
ranges and plateaus and extend for more than 300 km from
300
J. Yanai et al.
gas emissions and leaching of nitrate, and harmful
chemical substances are also discussed.
Keywords
Brown Forest soils Á Environmentally friendly
agriculture Á Fluvic soils Á Lake Biwa Á Paddy fields
9.1 Outline of the Kinki, Chugoku,
and Shikoku Regions
9.1.1 Perspective and Historical Background
The Kinki, Chugoku, and Shikoku regions are located in the
west-central part of Honshu Island, Shikoku Island, and
surrounding islands, and extend from roughly 32.7–35.8° N
latitude and 130.9–136.5° E longitude. The Kinki region is
administratively composed of six prefectures—Osaka,
Kyoto, Hyogo, Nara, Shiga, and Wakayama—with a total
area of 27.3 Â 10
3 km
2 (corresponding to 7.2% of the area of
Japan) and a total population of 20.68 million people (corresponding to 16.3% of the population of Japan; Ministry of
Internal Affairs and Communications, 2016). The Chugoku
region is administratively composed of five prefectures—
Tottori, Shimane, Okayama, Hiroshima, and Yamaguchi—
with a total area of 31.9 Â 10
3 km
2 (corresponding to 8.4%
of the area of Japan) and a total population of 7.41 million
people (corresponding to 5.8% of the population of Japan
2016). The Shikoku region is administratively composed of
four prefectures—Tokushima, Kagawa, Ehime, and Kochi—
with a total area of 18.3 Â 10
3 km
2 (corresponding to 4.8%
of the area of Japan) and a total population of 3.82 million
people (corresponding to 3.0% of the population of Japan,
2016). The three regions therefore have a combined area of
77.5 Â 10
3 km
2 (corresponding to 20.4% of the area of
Japan) and a combined population of 31.91 million people
(corresponding to 25.1% of the population of Japan 2016).
One of the characteristics of the Kinki, Chugoku, and
Shikoku regions is the early acceptance of the culture of the
Asian continent due to their proximity. Specifically, rice
farming was first introduced from China to Japan (northern
Kyushu) at the later stage of the Jomon period (fourth century BC), as evidenced by the Itatsuki ruins in Fukuoka
Prefecture and the Nahata ruins in Saga Prefecture. Rice
farming was quickly transferred to Eastern Japan and arrived
in northern Honshu at the early stage of the Yayoi period
(fourth century BC to the middle of the third century AD), as
evidenced by the Sunazawa ruins in Aomori Prefecture.
Accordingly, it is reasonable to assume that rice farming was
introduced in the Kinki, Chugoku, and Shikoku regions at a
relatively early stage of the Yayoi period. This would be
partly due to their climatic conditions, which are characterized by relatively warm temperature and plentiful precipitation, and to their geography, which consists of many rivers
and alluvial plains. Additionally, the pedological conditions
of these regions could be another reason for the early
introduction of rice farming; specifically, the distribution of
volcanic soils (Andosols) with high water permeability was
extraordinary sparse and such conditions made it easy to
prepare paddy fields, which require the storage of water for
rice production. In this sense, these regions must have
played a pioneering role during the nascent stage of rice
production in Japan.
Another characteristic of the Kinki, Chugoku, and Shikoku regions is their early development as centers of politics, economy, and culture, from (1) the Izumo Dynasty in
Shimane Prefecture and (2) the Yamato Dynasty in Nara
Prefecture, which named itself “the country of ripening rice”
and introduced an ancient land subdivision system, that is,
the strip system, and a system of periodic reallocation of
paddy fields to farmers, that is, “Handen-shuju-sei” (AD
652), for their governance, to (3) the capital of Heijo-kyo in
Nara Prefecture (AD 710) and 4) the capital of Heian-kyo in
Kyoto Prefecture (AD 794). It is highly probable that the
political, economic, and cultural importance of these three
regions was also strongly influenced by the specific conditions of these regions, including soil distributions.
The third characteristic of the Kinki, Chugoku, and Shikoku regions is their wide variety of population density,
from the second biggest metropolitan and economic center in
Japan (around Osaka; the biggest is in the Kanto region,
around Tokyo) to largely depopulated areas in some parts of
these regions. This variety affects the present land use and
soil management, including for agriculture and forestry.
9.1.2 Geomorphology
The landforms of these regions are classified into mountains
of the “inner zone” (north of the Median Tectonic Line
[MTL]), mountains of the “outer zone” (south of the MTL),
and in-between lowlands ranging from the Seto Inland Sea
to the Kinki triangle zone (Okada and Chinzei 2004).
Distinctive landform divisions in these regions are shown in
Fig. 9.1.
Mountains in the inner zone consist of the Tanba
mountains (1) in Fig. 9.1) in the north of Kyoto Prefecture
and the Chugoku mountains (2), which cover most of the
Chugoku region. In this zone, mountains higher than
1000 m above sea level (a.s.l.) are rare and the average
elevation is 800–900 m a.s.l. The relief of these mountains is
mostly gentle. The Chugoku mountains include backbone
ranges and plateaus and extend for more than 300 km from
300
J. Yanai et al.