showed that the nitrogen flux from a paddy rice field can be
reduced by these technologies, and that they can also
maintain soil fertility and increase it (Tanaka 2001). A green
manure cultivation technique, which utilizes nitrogen in the
forage legume grown after paddy rice harvesting as a basal
fertilizer for the next crop of rice, has also been developed in
three prefectures (Osaka, Hyogo, and Okayama). This
technique is used for the distinctive cultivation of paddy rice
as well as to allow a decrease in chemical fertilizer
application.
(2) Upland fields
In order to achieve high profits in upland fields, particularly
for vegetable cropping, fertilization and soil amendment are
conducted to a large degree. Therefore, excesses of soil
nutrients such as P 2 O 5 and CaO, unbalances in soil nutrients,
and the leaching of nitrate from upland fields to the environment will be often a problem due to the high application
amounts of fertilizer and soil amendments, which leads to a
rise in fertilizer cost. Therefore, technical development to
decrease the application amounts of fertilizer, such as the
utilization of controlled-release fertilizer and the introduction
of local fertilization technology, has been advanced in four
prefectures (Shiga, Hyogo, Shimane, and Okayama).
A method for estimating the amount of fertilizer which has
accumulated in soil and to decrease the application amount
of fertilizer has also been developed in three prefectures
(Osaka, Tokushima, and Kochi). Additionally, an automated
pulsating drip irrigation system using a solar pump was
developed by the Western Region Agricultural Research
Center (Yoshikawa and Nakao 2010). Since the system has a
better water and nitrogen use efficiency than the conventional system, yield improvement and a reduction of the
amount of nitrogen fertilization can be achieved at the same
time for various kinds of vegetables.
(3) Orchards
Clean-cultured soil surface management, in which weeds
are not grown, was previously used at orchards. However,
due to the availability of passenger-type mowers, the conduction of weed-cultured soil surface management, in which
weeds are grown and cut periodically, has been increasing
recently. In the Kansai region, because of the presence of
many orchards in hilly and semimountainous areas, the
introduction of this weed-cultured management contributes
to the prevention of soil erosion and nutrient leaching.
However, the Kansai region contains mineral-rich soil, and
the topsoil layer is shallow. Therefore, there is a fear of
water and nutrient competition between fruits and weeds
during weed-cultured management in this region. The
development of fertilization technology in weed-cultured
orchards will be needed from now on. On the other hand, the
level of nitrogen fertilizer application is generally high in tea
plantations, and accordingly there were fears of nitrate–nitrogen leaching. However, the utilization of controlledrelease fertilizer such as coated urea enabled the amounts of
fertilization to be reduced substantially (Shiwa et al. 2000).
(4) Evaluation technique for fertilization rate of applied
livestock manure
In the Kansai region, particularly the Chugoku and Shikoku
regions, dairy and poultry are raised extensively and livestock manure has been widely produced and circulated.
Livestock manure was used as a soil amendment in the past,
and the fertilization rate was not considered. However, more
recently, environmentally friendly agriculture has spread,
and the consciousness of fertilizer cost reduction has risen.
Therefore, the development of techniques to evaluate the
appropriate fertilization rate of the applied livestock manure
has been advanced in three prefectures (Okayama Prefecture
2013; Hiroshima; Yamaguchi). As a result, the appropriate
fertilization rate of livestock manure has become clear,
which is useful for the reduction of fertilizer cost and
avoiding the accumulation of soil nutrients.
References
Aber JD, Acdowell W et al (1998) Nitrogen saturation in temperate
forest ecosystems—hypothesis revisited. Bioscience 48:921–934
Agency for Cultural Affairs (2017) On important cultural landscapes.
(in Japanese)
Barnes GL (1986) Paddy field archaeology in Nara, Japan. J Field
Archaeol 13:371–379
Board of Audit of Japan (2016) Present situation of the regulation of
rice production (Appended table 10: Percentage of conversion to
non-rice crops in every prefecture in Japan). http://report.jbaudit.go.
jp/org/h27/ZUIJI7/2015-h27-Z7105-0.htm. (in Japanese)
Council of Investigation for Soil Conservation (2012) The guidebook
of agricultural soil in Japan. Japan Soil Association Tokyo 77–99.
(in Japanese)
Forest Agency (2016) Annual report on trends in forests and forestry.
Tokyo
Forestry Agency (2017) Forest ratio and Planted forest ratio listed by
prefectures on March 31, 2012. http://www.rinya.maff.go.jp/j/
keikaku/genkyou/h24/1.html. (in Japanese)
Hasegawa K (1992) Studies on the behavior and balance of nitrogen in
paddy field near the lake and its influence on environment especially
on the water quality. Spec Bull Shiga Agric Exp Stn 17:1–164 (in
Japanese with English summary)
Hasukawa H, Shibahara F et al (2011) Runoff load reduction by
improved soil management practice in paddy rice non-cropping
period. Bull Shiga Pref Agric Tech Promo Cent 50:47–59 (in
Japanese with English summary)
Hirai Y (2004) Plains of Shikoku side. In Ota Y, Nause T, Tanaka S,
Okada A (eds) Regional geomorphology of the Japanese Islands,
324
J. Yanai et al.
reduced by these technologies, and that they can also
maintain soil fertility and increase it (Tanaka 2001). A green
manure cultivation technique, which utilizes nitrogen in the
forage legume grown after paddy rice harvesting as a basal
fertilizer for the next crop of rice, has also been developed in
three prefectures (Osaka, Hyogo, and Okayama). This
technique is used for the distinctive cultivation of paddy rice
as well as to allow a decrease in chemical fertilizer
application.
(2) Upland fields
In order to achieve high profits in upland fields, particularly
for vegetable cropping, fertilization and soil amendment are
conducted to a large degree. Therefore, excesses of soil
nutrients such as P 2 O 5 and CaO, unbalances in soil nutrients,
and the leaching of nitrate from upland fields to the environment will be often a problem due to the high application
amounts of fertilizer and soil amendments, which leads to a
rise in fertilizer cost. Therefore, technical development to
decrease the application amounts of fertilizer, such as the
utilization of controlled-release fertilizer and the introduction
of local fertilization technology, has been advanced in four
prefectures (Shiga, Hyogo, Shimane, and Okayama).
A method for estimating the amount of fertilizer which has
accumulated in soil and to decrease the application amount
of fertilizer has also been developed in three prefectures
(Osaka, Tokushima, and Kochi). Additionally, an automated
pulsating drip irrigation system using a solar pump was
developed by the Western Region Agricultural Research
Center (Yoshikawa and Nakao 2010). Since the system has a
better water and nitrogen use efficiency than the conventional system, yield improvement and a reduction of the
amount of nitrogen fertilization can be achieved at the same
time for various kinds of vegetables.
(3) Orchards
Clean-cultured soil surface management, in which weeds
are not grown, was previously used at orchards. However,
due to the availability of passenger-type mowers, the conduction of weed-cultured soil surface management, in which
weeds are grown and cut periodically, has been increasing
recently. In the Kansai region, because of the presence of
many orchards in hilly and semimountainous areas, the
introduction of this weed-cultured management contributes
to the prevention of soil erosion and nutrient leaching.
However, the Kansai region contains mineral-rich soil, and
the topsoil layer is shallow. Therefore, there is a fear of
water and nutrient competition between fruits and weeds
during weed-cultured management in this region. The
development of fertilization technology in weed-cultured
orchards will be needed from now on. On the other hand, the
level of nitrogen fertilizer application is generally high in tea
plantations, and accordingly there were fears of nitrate–nitrogen leaching. However, the utilization of controlledrelease fertilizer such as coated urea enabled the amounts of
fertilization to be reduced substantially (Shiwa et al. 2000).
(4) Evaluation technique for fertilization rate of applied
livestock manure
In the Kansai region, particularly the Chugoku and Shikoku
regions, dairy and poultry are raised extensively and livestock manure has been widely produced and circulated.
Livestock manure was used as a soil amendment in the past,
and the fertilization rate was not considered. However, more
recently, environmentally friendly agriculture has spread,
and the consciousness of fertilizer cost reduction has risen.
Therefore, the development of techniques to evaluate the
appropriate fertilization rate of the applied livestock manure
has been advanced in three prefectures (Okayama Prefecture
2013; Hiroshima; Yamaguchi). As a result, the appropriate
fertilization rate of livestock manure has become clear,
which is useful for the reduction of fertilizer cost and
avoiding the accumulation of soil nutrients.
References
Aber JD, Acdowell W et al (1998) Nitrogen saturation in temperate
forest ecosystems—hypothesis revisited. Bioscience 48:921–934
Agency for Cultural Affairs (2017) On important cultural landscapes.
(in Japanese)
Barnes GL (1986) Paddy field archaeology in Nara, Japan. J Field
Archaeol 13:371–379
Board of Audit of Japan (2016) Present situation of the regulation of
rice production (Appended table 10: Percentage of conversion to
non-rice crops in every prefecture in Japan). http://report.jbaudit.go.
jp/org/h27/ZUIJI7/2015-h27-Z7105-0.htm. (in Japanese)
Council of Investigation for Soil Conservation (2012) The guidebook
of agricultural soil in Japan. Japan Soil Association Tokyo 77–99.
(in Japanese)
Forest Agency (2016) Annual report on trends in forests and forestry.
Tokyo
Forestry Agency (2017) Forest ratio and Planted forest ratio listed by
prefectures on March 31, 2012. http://www.rinya.maff.go.jp/j/
keikaku/genkyou/h24/1.html. (in Japanese)
Hasegawa K (1992) Studies on the behavior and balance of nitrogen in
paddy field near the lake and its influence on environment especially
on the water quality. Spec Bull Shiga Agric Exp Stn 17:1–164 (in
Japanese with English summary)
Hasukawa H, Shibahara F et al (2011) Runoff load reduction by
improved soil management practice in paddy rice non-cropping
period. Bull Shiga Pref Agric Tech Promo Cent 50:47–59 (in
Japanese with English summary)
Hirai Y (2004) Plains of Shikoku side. In Ota Y, Nause T, Tanaka S,
Okada A (eds) Regional geomorphology of the Japanese Islands,
324
J. Yanai et al.