soils in the WRB classification system, whereas the alteration of land and transferred soils are the main diagnostic
characteristic for soils in anthropized environments in the
USDA Soil Taxonomy. The central concept of the Japanese
classification system does not translate well to the USDA
classification system, but is relatively close to that of the
WRB classification system with a narrower range of applications. In the Japanese classification, the concept of soils
which have the potential to be responsible for primary productivity can be close to that in the USDA classification
system (Kida and Kawahigashi 2017).
The definition of the top of a soil surface directly influences the stated vertical position of any diagnostic horizons
for soil classification (Kida and Kawahigashi 2017). The
definition of soil surface in the Japanese classification system is the mineral soil surface, as opposed to the ground
surface which is the definition used for soil surface in the
WRB classification system. The difference in the definitions
of soil surface between classification systems differentiates
the position of diagnostic horizons in a soil horizon, affecting the soil name and the translation of the soil name
between the systems.
4.1.4 Distribution of Human-Made Soils
in Japan
(1) Settlement areas in Japan
Areas of human settlement, which occupy almost 10% of
Japan’s land area, have been artificially modified by large-scale
civil engineering works. The total settlement area has increased
during the past several decades, accompanied by a decrease in
the area of agricultural fields (Fig. 4.3). In civil engineering, a
large volume of soil, reaching approximately 300 million m
3
every year, is transferred from one site to another, mainly to
make flat land (Katsumi 2015). The process of cutting and
banking soils forms a new soil profile, leading to an increase in
the area of Artifactual soils and Reformed soils. However, the
processed area covered with constructions, which occupies
approximately 80% of settlement areas (Ministry of Land,
Infrastructure and Transport 2014; Fig. 4.4), is excluded from
classification under the Soil Classification System of Japan.
This means that most of the land area in urban areas, which is
covered with artifacts, is not considered to be areas where
Human-made soils are distributed.
The remaining 20% of settlement areas is occupied by
greenery areas, which include recreation areas such as golf
courses and ski slopes that required land-forming construction (Fig. 4.4). These artificially formed soils are frequently
excluded from the definition of Human-made soils because
the soils used on-site to flatten land for construction of road
Fig. 4.3 Change in the area of agricultural land and settlement area in
land use change in Japan from 1984 to 2012. The settlement area
consisting of residential and road areas does not include recreation areas,
greenery areas, and reclaimed lands. The figure was created by the
authors based on data from white papers on land published by Ministry
of Land, Infrastructure, Transport and Tourism of Japan (MLIT 2014)
Fig. 4.4 Composition in land uses in the extended settlement of Japan.
The figure was created by the authors based on data from “Greenhouse
Gas Inventory Report of Japan 2012” published from Greenhouse Gas
Inventory Office of Japan (GIO) and databases from Ministry of Land,
Infrastructure, Transport and Tourism of Japan (MLIT 2014). Residential, Road, and Industry areas were the statistical data of white
papers on land (MLIT 2014). These three areas were subtracted from
total area of the extended settlement (GIO 2012) to calculate the area of
“others” which include greenery areas, golf courses, reclaimed land
areas and unknown land uses
4 Major Soil Types
73
characteristic for soils in anthropized environments in the
USDA Soil Taxonomy. The central concept of the Japanese
classification system does not translate well to the USDA
classification system, but is relatively close to that of the
WRB classification system with a narrower range of applications. In the Japanese classification, the concept of soils
which have the potential to be responsible for primary productivity can be close to that in the USDA classification
system (Kida and Kawahigashi 2017).
The definition of the top of a soil surface directly influences the stated vertical position of any diagnostic horizons
for soil classification (Kida and Kawahigashi 2017). The
definition of soil surface in the Japanese classification system is the mineral soil surface, as opposed to the ground
surface which is the definition used for soil surface in the
WRB classification system. The difference in the definitions
of soil surface between classification systems differentiates
the position of diagnostic horizons in a soil horizon, affecting the soil name and the translation of the soil name
between the systems.
4.1.4 Distribution of Human-Made Soils
in Japan
(1) Settlement areas in Japan
Areas of human settlement, which occupy almost 10% of
Japan’s land area, have been artificially modified by large-scale
civil engineering works. The total settlement area has increased
during the past several decades, accompanied by a decrease in
the area of agricultural fields (Fig. 4.3). In civil engineering, a
large volume of soil, reaching approximately 300 million m
3
every year, is transferred from one site to another, mainly to
make flat land (Katsumi 2015). The process of cutting and
banking soils forms a new soil profile, leading to an increase in
the area of Artifactual soils and Reformed soils. However, the
processed area covered with constructions, which occupies
approximately 80% of settlement areas (Ministry of Land,
Infrastructure and Transport 2014; Fig. 4.4), is excluded from
classification under the Soil Classification System of Japan.
This means that most of the land area in urban areas, which is
covered with artifacts, is not considered to be areas where
Human-made soils are distributed.
The remaining 20% of settlement areas is occupied by
greenery areas, which include recreation areas such as golf
courses and ski slopes that required land-forming construction (Fig. 4.4). These artificially formed soils are frequently
excluded from the definition of Human-made soils because
the soils used on-site to flatten land for construction of road
Fig. 4.3 Change in the area of agricultural land and settlement area in
land use change in Japan from 1984 to 2012. The settlement area
consisting of residential and road areas does not include recreation areas,
greenery areas, and reclaimed lands. The figure was created by the
authors based on data from white papers on land published by Ministry
of Land, Infrastructure, Transport and Tourism of Japan (MLIT 2014)
Fig. 4.4 Composition in land uses in the extended settlement of Japan.
The figure was created by the authors based on data from “Greenhouse
Gas Inventory Report of Japan 2012” published from Greenhouse Gas
Inventory Office of Japan (GIO) and databases from Ministry of Land,
Infrastructure, Transport and Tourism of Japan (MLIT 2014). Residential, Road, and Industry areas were the statistical data of white
papers on land (MLIT 2014). These three areas were subtracted from
total area of the extended settlement (GIO 2012) to calculate the area of
“others” which include greenery areas, golf courses, reclaimed land
areas and unknown land uses
4 Major Soil Types
73