Brown Forest soils and another soil great group have both or
alternating characteristics of the soil great groups. Such soils
are classified at the subgroup level of Brown Forest soils.
(2) Soil group
In the Soil Classification System of Japan (2017), the Brown
Forest soil great group only consists of the Brown Forest soil
group. Because the Japanese archipelago has a wide range of
climatic conditions, the Brown Forest soil great group is
considered to have various characteristics corresponding to
climatic differences. Soils under warm temperate forest were
regarded as “warm temperate forest soils” (Endo 1966) or
“yellow-brown forest soils” (Nagatsuka 1975), which were
different from the “brown forest soils” under cool temperate
forest. The Unified Soil Classification System of Japan (first
approximation) (Committee for Soil Classification and
Nomenclature 1986) followed these ideas and classified soils
developed under warm temperate forest as “yellow-brown
forest soils” and soils developed under cool temperate forest
as “brown forest soils.” A subsequent classification system
(The Fourth Committee for Soil Classification and Nomenclature the Japanese Society of Pedology 2003) also keyed out
“yellow-brown forest soils” from “brown forest soils” using
soil color and organic carbon content as diagnostic criteria.
However, these classifications did not consider the influence
of volcanic ash on “brown forest soils.” Considering the
influence of volcanic ash and comparing only soils with little
or no influence from volcanic ash, the colors of subsurface
Fig. 4.45 Vertical distribution
of SRO Al and Fe compounds in
Brown Forest soil and Andosol
profiles. Data source Imaya et al.
(2007)
Fig. 4.46 Soil profile of Andic Brown Forest soil (Andic Dystrudept)
under deciduous evergreen forest in Sefuri Mountains, Saga, Japan
Photograph A. Imaya
116
Y. Takata et al.
alternating characteristics of the soil great groups. Such soils
are classified at the subgroup level of Brown Forest soils.
(2) Soil group
In the Soil Classification System of Japan (2017), the Brown
Forest soil great group only consists of the Brown Forest soil
group. Because the Japanese archipelago has a wide range of
climatic conditions, the Brown Forest soil great group is
considered to have various characteristics corresponding to
climatic differences. Soils under warm temperate forest were
regarded as “warm temperate forest soils” (Endo 1966) or
“yellow-brown forest soils” (Nagatsuka 1975), which were
different from the “brown forest soils” under cool temperate
forest. The Unified Soil Classification System of Japan (first
approximation) (Committee for Soil Classification and
Nomenclature 1986) followed these ideas and classified soils
developed under warm temperate forest as “yellow-brown
forest soils” and soils developed under cool temperate forest
as “brown forest soils.” A subsequent classification system
(The Fourth Committee for Soil Classification and Nomenclature the Japanese Society of Pedology 2003) also keyed out
“yellow-brown forest soils” from “brown forest soils” using
soil color and organic carbon content as diagnostic criteria.
However, these classifications did not consider the influence
of volcanic ash on “brown forest soils.” Considering the
influence of volcanic ash and comparing only soils with little
or no influence from volcanic ash, the colors of subsurface
Fig. 4.45 Vertical distribution
of SRO Al and Fe compounds in
Brown Forest soil and Andosol
profiles. Data source Imaya et al.
(2007)
Fig. 4.46 Soil profile of Andic Brown Forest soil (Andic Dystrudept)
under deciduous evergreen forest in Sefuri Mountains, Saga, Japan
Photograph A. Imaya
116
Y. Takata et al.