http://www.fao.org/globalsoilpartnership This presentation was made during the Asian Soil Partnership workshop that took place in Bangkok, Thailand 13-15 May 2015. This presentation was made by Kazuyuki Yagi, and it presents status of national soil resources for Japan. ©FAO: http://www.fao.org

1. Status of National Soil
Resources for Japan
Kazuyuki Yagi
National Institute for Agro-Environmental Sciences,
Tsukuba, Japan
Asian Soil Partnership Consultation Workshop on Sustainable
Management and Protection of Soil Resources
13-15 May 2015, Bangkok, Thailand

2. Japan: Geography and Climate
Japan has a total of 6,852 islands extending along the Pacific
coast of East Asia, lies between latitudes 24º-46ºN.
The climate of Japan is predominantly temperate, but varies
greatly from north to south. Pacific summer monsoon brings
warm and humid, while Siberian winter monsoon brings cold
weather. The average winter temperature in Japan is 5.1ºC
and the average summer temperature is 25.2ºC .
About 66% of Japan’s land is covered with forest land, and
12% with agricultural land.

3. Japan: Distribution of Major Soils in
Agricultural Land
B. Peat soil
D. Andosol
H. Red-
yellow soil
I. Brown
forest soil
F. Fluvic soil

4. Japan: Distributions of Soil Types in
Agricultural Lands
Paddy
Upland Crop
Grass land
2.81 M ha
Gley soils
(Fluvisols)
16%
Gleyic Andosols
(Gleic Andosols)
6%
Others
11%
Others 9%
Others
6%
Andosols
10%
Brown Forest
soils (Cambisols)
3%
3%
2%
Others
4%
Orchard
1.29 M ha
0.69 M ha
0.44 M ha
19%
Brown Lowland
soils (Fluvisols)
3%
Gray Lowland soils
(Fluvisols, Gleysols)
Andosols 6%
Brown Forest
soils (Cambisols)
2%
3%
Brown Lowland
soils (Fluvisols)
Brown Forest
soils (Cambisols)
Andosols

5. Japan: Main Issues of Soil Management
 Soil fertility management
− Sustainability of soil fertility
− Soil management for quality and quantity of products
 Environmental assessment
− Soil management for eco-farming
− Contamination of pollutants (heavy metal, organic
pollutants, radionuclides, etc.)
− Soil C losses/sequestration and GHG emissions
 Continuation of soil monitoring
 Improvement of soil information system
 Capacity building and education

6. Stationary monitoring points
Starting in 1979
Quinquennial sampling at
about 20,000 sites up to 4th
monitoring (1979-1998)
About 4,000 sites since 5th
monitoring (1999-present)
 Soil profile description
(classification)
 Physico-chemical properties
 soil management record
(questionnaire survey)
National Agricultural Soil Monitoring

7. Soil Erodibility
(K) factor Map
Application of soil inventory in Japanese agricultural land
Soil Carbon
Stock Map
Radioactive Cs
Concentration map
(Aug. 2011)
Available Water
Content
Soil Nitrogen
Stock Map
Soil Temperature
Map
Agro-environmental indicators

8. Japan: Major Threats for Soil Resources
 Soil organic carbon losses
 Soil contamination
− Heavy metals (Cd, Cu, and As)
− Radioactive Cs
 Nutrient imbalance
− Excess N and P
 Soil erosion
− Water erosion
 Soil sealing and capping

9. Long-term Experiments in Japan
○ Since 1975, the MAFF has conducted long-term experiments with continuous
organic matter application under typical soil type and cropping system of each
prefecture (over 150 sites in total), which demonstrated that soil carbon stock
increased through organic matter application such as compost.
○ Example of long-term experiment (Gray Lowland Soil; upland)
化 学 肥 料 単 用 区
稲 わ ら た い 肥 0 .2 5 t 区
稲 わ ら た い 肥 0 .7 5 t 区
0.5
1
1.5
2
2.5
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
（連 用 年 数 ）
（全 炭 素 (%)）Total C (%)
Years
Plot with Chemical Fertilizer Only
Plot with Rice Straw Compost (2.5t/ha/year)
Plot with Rice Straw Compost (7.5t/ha/year)
Data：”Basic Survey of Soil Environment (Benchmark Survey)” Yamaguchi Pref. Agricultural
Research Institute. Figure for a year is the three-year average including the previous and the
next year to that year.

10. 530
540
550
560
570
580
590
600
610
1980 1990 2000 2010 2020
農地土壌炭素量（百万トン）
年
緩和シナリオ
BAUシナリオ
国際的な基準年（1990年）
における土壌炭素変化量
約束期間（2013～2020年）
における土壌炭素変化量
緩和シナリオ（有機物投
入量を増大した場合）
BAUシナリオ（現在の農
地管理をそのまま継続し
た場合）
SoilCstock(millionton)
High OM
BAU
C stock change in 1990
year
C stock change during
2013-2020
Higher inputs of
manure and residue
Business as usual
scenario (lower OM
inputs)
Soil C Stock Change in Japanese Agricultural Lands
Results of RothC Model Simulation
Japanese agricultural lands have a potential of 1 to 4 million tons
of CO2 sequestration during 2013-2020 compared to 1990.

11. Soil Cd pollution caused by mine; Akita prefecture
（Ogawa 1994）
Cd指定面積
2007年全国合計
6,429 ha
Once the site of mining
Cd汚染米産出地域
Cd汚染米は産出しないが
土壌Cdなどが高い地域
11
Area of Cd contaminated
rice being produced

12. Fukushima Dai-ichi Neuclear power plant
(photo by TEPCO)
Soil sampling in paddy field
Measurement of aerial dose rate Soil sampler
Radioactive contamination in farmland soil

13. Fukushima Prefecture
Fukushima City
Ministry of Agriculture, Forestry and Fisheries Research Council http://www.s.affrc.go.jp/docs/map/240323.htm
Radioactive Cs Map for Agricultural Lands

14. Class
Degree of soil
erosion
Amount
( t ha-1
y-1
)
Share
(%)
Ⅰ Slight ＜１ 43
Ⅱ Few １～ ５ 18
Ⅲ
Few-moderate
(acceptable) ５～１０ 9
Ⅳ
Moderate-severe
(not acceptable) １０～３０ 12
Ⅴ severe ３０～５０ 5
Ⅵ Very severe ５０ ≦ 14
Map for soil erosion risk in cultivated land in Japan
Soil erosion risk indicator

15. Japan: National Priorities for
Sustainable Soil Management
 To develop indicators for sustainable soil management,
especially those for:
− decreasing environmental risks, such as climate
change, nutrient imbalance, and contamination of
radionuclides and heavy metals
− sustaining soil fertility and productivity in the
systems of environmentally-sound agricultural
 To continue national-wide soil monitoring
 To improve soil information system for public use
 To inherit soil knowledge to the next generation

16. Conserve the environment by listening to wind,
observing soil and thinking of our future