and Sorachi areas are used as paddy fields. Peat soils are
mainly distributed in gentle streams of rivers and backmarshes, common in the Ishikari and Sorachi areas. These
areas have a high groundwater level, poor drainage, and low
bearing capacity.
(2) Land consolidation projects in paddy fields
In Hokkaido, many paddy fields are poorly drained and
unsuitable for use as agricultural land. Therefore, the consolidation of drainage canals and subsurface drainage by
Table 5.1 Distribution rate of soil types in Hokkaido with the Soil Classification System of Japan and the relationship to Hokkaido agricultural
diagnostic soil types
Great Groups
Groups
(%)
(%)
Organic Soils
3.3
8.6
Peatsoils
3.3
8.6
I. Peat soils
Andosols
41.8
40.9
Podzolic Andsols
<0.1
0.0
-
Regosolic Andosols
7.0
7.8
II. Volcanic soils
Gleyed Andosols
<0.1
0.1
II. Volcanic soils
Wet Andosols
0.0
6.7
II. Volcanic soils
Non-allophanic Andosols
6.0
1.4
II. Volcanic soils
Allophanic Andosols
28.0
24.9
II. Volcanic soils
Podzols
1.2
0.0
Podzols
1.2
<0.1
(not fixed)
Fluvic soils
10.3
28.7
Fluvic Paddy soils
0.2
0.0
-
Gley Fluvic soils
1.4
5.5
III. Low land soils
Gray Fluvic soils
2.6
9.2
III. Low land soils
Brown Fluvic soils
5.3
13.8
III. Low land soils
Regosolic Fluvic soils
0.8
<0.1
III. Low land soils
Red-Yellow soils
0.9
1.9
Argic Red-Yellow soils
<0.1
1.0
IV. Terrestrial soils
Cambic Red-Yellow soils
0.9
0.8
IV. Terrestrial soils
Stagnic soils
1.8
7.8
Stagnogley soils
<0.1
0.5
IV. Terrestrial soils
Pseudogley soils
1.8
7.3
IV. Terrestrial soils
Eutrosols
<0.1
0.0
Magnesian Eutrosols
<0.1
0.0
-
Calcareous Eutrosols
<0.1
0.0
-
Brown Forest soils
31.9
9.8
Brown Forest soils
31.9
9.8
IV. Terrestrial soils
Regosols
8.1
2.3
Volcanogenous Regosols
4.9
2.0
II. Volcanic soils
Sandy Regosols
0.6
0.3
(not fixed)
Lithosols
0.9
<0.1
-
Terrestrial Regosols
1.8
<0.1
-
Others
0.6
-
Rocks and Stone
<0.1
-
City and Water
0.6
-
total
100.0
100.0
total area (km
2 )
* official data of w hole area is 83,424 (km
2 )
** official data in 2010 of cultivated area
italic : soil group w ith no distribution
Classification System of Japan
Whole area
Cultivated area
Relationship to
Hokkaido agricultural
diagnostic soiltypes
81,488*
11,556**
5 Hokkaido Region
139
mainly distributed in gentle streams of rivers and backmarshes, common in the Ishikari and Sorachi areas. These
areas have a high groundwater level, poor drainage, and low
bearing capacity.
(2) Land consolidation projects in paddy fields
In Hokkaido, many paddy fields are poorly drained and
unsuitable for use as agricultural land. Therefore, the consolidation of drainage canals and subsurface drainage by
Table 5.1 Distribution rate of soil types in Hokkaido with the Soil Classification System of Japan and the relationship to Hokkaido agricultural
diagnostic soil types
Great Groups
Groups
(%)
(%)
Organic Soils
3.3
8.6
Peatsoils
3.3
8.6
I. Peat soils
Andosols
41.8
40.9
Podzolic Andsols
<0.1
0.0
-
Regosolic Andosols
7.0
7.8
II. Volcanic soils
Gleyed Andosols
<0.1
0.1
II. Volcanic soils
Wet Andosols
0.0
6.7
II. Volcanic soils
Non-allophanic Andosols
6.0
1.4
II. Volcanic soils
Allophanic Andosols
28.0
24.9
II. Volcanic soils
Podzols
1.2
0.0
Podzols
1.2
<0.1
(not fixed)
Fluvic soils
10.3
28.7
Fluvic Paddy soils
0.2
0.0
-
Gley Fluvic soils
1.4
5.5
III. Low land soils
Gray Fluvic soils
2.6
9.2
III. Low land soils
Brown Fluvic soils
5.3
13.8
III. Low land soils
Regosolic Fluvic soils
0.8
<0.1
III. Low land soils
Red-Yellow soils
0.9
1.9
Argic Red-Yellow soils
<0.1
1.0
IV. Terrestrial soils
Cambic Red-Yellow soils
0.9
0.8
IV. Terrestrial soils
Stagnic soils
1.8
7.8
Stagnogley soils
<0.1
0.5
IV. Terrestrial soils
Pseudogley soils
1.8
7.3
IV. Terrestrial soils
Eutrosols
<0.1
0.0
Magnesian Eutrosols
<0.1
0.0
-
Calcareous Eutrosols
<0.1
0.0
-
Brown Forest soils
31.9
9.8
Brown Forest soils
31.9
9.8
IV. Terrestrial soils
Regosols
8.1
2.3
Volcanogenous Regosols
4.9
2.0
II. Volcanic soils
Sandy Regosols
0.6
0.3
(not fixed)
Lithosols
0.9
<0.1
-
Terrestrial Regosols
1.8
<0.1
-
Others
0.6
-
Rocks and Stone
<0.1
-
City and Water
0.6
-
total
100.0
100.0
total area (km
2 )
* official data of w hole area is 83,424 (km
2 )
** official data in 2010 of cultivated area
italic : soil group w ith no distribution
Classification System of Japan
Whole area
Cultivated area
Relationship to
Hokkaido agricultural
diagnostic soiltypes
81,488*
11,556**
5 Hokkaido Region
139