Terrestrial Regosols contain free calcium carbonate, resulting in a soil pH of about 8, and their soil texture is mainly
light clay to silty clay. The common characteristics of these
soils are their low organic matter contents.
The conventional fertilizer application levels for sugarcane are 200–300 kg ha
−1 of nitrogen, 60–120 kg ha
−1 of
phosphate, and 60–100 kg ha
−1 of potassium, although there
are some differences depending on region and cropping type
(Okinawa Prefecture 2014). According to the
Soil-Environmental Monitoring Project conducted between
1979 and 1999, the available phosphate contents in sugarcane fields increased from 200 to 600 mg kg
−1 over these
20 years (Kuniyoshi and Gima 2004). Accordingly, the
reduction of phosphate fertilizer has been recommended.
The main soil chemical and physical properties affecting
sugarcane yield in the Nansei Islands are soil available
nitrogen level and plow layer depth (Yoshida et al. 2016).
The soil available nitrogen content is significantly lower in
the Nansei Islands than in other parts of Japan; the average
soil available nitrogen level in Japanese upland soils is 53.0–
59.0 mg kg
−1 , while that in the sugarcane fields in Kitadaito
Island (Nansei Islands) is 13.6 mg kg
−1 (Yoshida et al.
2016).
Generally, the clay contents of soils in the Nansei Islands
are high, and the subsoils tend to be easily compacted
(Tokashiki 1993). Consequently, hardpan forms under the
weight of large machinery (such as cane harvesters), which
has harmful effects on sugarcane growth (Kameya 2006). It
is important to increase the plow layer depth by applying
organic matter such as compost or green manure or by
performing subsoiling or deep tillage for soil management in
the Nansei Islands.
Studies on the long-term application of organic matter in
a sugarcane field showed that the total soil carbon content
increased and the sugarcane yield increased by 10–22% after
the application of 50 Mg ha
−1 or more (Goto and Nagata
2008). Moreover, Miyamaru et al. (2012) reported that the
carbon and nitrogen contents of soil microbial biomass
significantly increased after the application of organic matter, which increased the level of soil available nitrogen in
upland soils. Furthermore, the application of cane molasses,
a byproduct of sugarcane production, also increased the
levels of soil available nitrogen and improved the sugarcane
yield by 20–30% (Yoshida et al. 2017). It was suggested that
easily decomposable organic matter such as sucrose in
molasses increased the amount of microbial biomass and as a
result increased the level of soil available nitrogen.
The destruction of the hardpan layer is generally performed by subsoiling. Additionally, it is reported that
subsoiling increases sugarcane yield by 12% (Oshiro and
Hamakawa 1980). It has also been noted that subsoiling
improves the soil water-holding capacity and drainage
conditions as well as softening the soil (Onaga and Gibo
1984; Shinzato et al. 2013). Sugarcane is a deep-rooted
crop and the effect of irrigation on the yield is therefore
high, although in some cases negative effects on sugarcane
growth are seen due to poor drainage. Therefore, subsoiling
is suitable as a soil management method for sugarcane
fields.
10.3.8 Globally Important Agricultural Heritage
Systems
The modern agricultural system has succeeded in supplying
food for a growing population but has also resulted in
environmental problems such deforestation, water pollution,
climate change, and so on throughout the globe, causing the
extinction of unique local cultures and the destruction of
landscapes and biodiversity. Nevertheless, it is evident that
in many parts of the world, unique systems of agriculture
have been maintained. Traditional agriculture, including
knowledge systems, adapted technologies, landscapes, and
biodiversity, continues to be protected from the adverse
effects of modernization.
The Food and Agriculture Organization of the United
Nations (FAO) is designating certain areas as globally
important agricultural heritage systems (GIAHS) in order to
maintain and preserve such agricultural systems in an integrated manner for the next generation. GIAHS are defined as
“remarkable land use systems and landscapes which are rich
in globally significant biological diversity evolving from the
co-adaptation of a community with its environment and
needs and aspirations for sustainable development” (FAO
2002).
As of 2018, 50 sites in 20 countries in the world, 11 of
which are in Japan, had been designated as GIAHS. Three
sites have been designated in Kyushu: the Aso Grasslands,
the
Kunisaki
Peninsula
Usa
area,
and
the
Takachihogo-Shiibayama area. The following subsections
introduce the soil management in these sustainable agricultural systems.
(1) The Aso Grasslands
The Aso Grasslands in Kumamoto prefecture, located in
central Kyushu, is the largest grassland area in Japan, covering about 220 km
2 (Miyabuchi and Sugiyama 2008). The
Aso Grasslands are a secondary (or semi-natural) grassland
composed mostly of Miscanthus (Japanese pampas grass),
Pleioblastus (warm temperate dwarf bamboo), and Zoysia
(Miyabuchi and Sugiyama 2016). The Aso Grasslands
continue under the balance of receiving artificial disturbance
and natural reformation. Since the Aso Grasslands are connected with both livestock rearing and local farming through
the use of the biomass of the grasslands as green manure and
348
Y. Arakawa et al.
light clay to silty clay. The common characteristics of these
soils are their low organic matter contents.
The conventional fertilizer application levels for sugarcane are 200–300 kg ha
−1 of nitrogen, 60–120 kg ha
−1 of
phosphate, and 60–100 kg ha
−1 of potassium, although there
are some differences depending on region and cropping type
(Okinawa Prefecture 2014). According to the
Soil-Environmental Monitoring Project conducted between
1979 and 1999, the available phosphate contents in sugarcane fields increased from 200 to 600 mg kg
−1 over these
20 years (Kuniyoshi and Gima 2004). Accordingly, the
reduction of phosphate fertilizer has been recommended.
The main soil chemical and physical properties affecting
sugarcane yield in the Nansei Islands are soil available
nitrogen level and plow layer depth (Yoshida et al. 2016).
The soil available nitrogen content is significantly lower in
the Nansei Islands than in other parts of Japan; the average
soil available nitrogen level in Japanese upland soils is 53.0–
59.0 mg kg
−1 , while that in the sugarcane fields in Kitadaito
Island (Nansei Islands) is 13.6 mg kg
−1 (Yoshida et al.
2016).
Generally, the clay contents of soils in the Nansei Islands
are high, and the subsoils tend to be easily compacted
(Tokashiki 1993). Consequently, hardpan forms under the
weight of large machinery (such as cane harvesters), which
has harmful effects on sugarcane growth (Kameya 2006). It
is important to increase the plow layer depth by applying
organic matter such as compost or green manure or by
performing subsoiling or deep tillage for soil management in
the Nansei Islands.
Studies on the long-term application of organic matter in
a sugarcane field showed that the total soil carbon content
increased and the sugarcane yield increased by 10–22% after
the application of 50 Mg ha
−1 or more (Goto and Nagata
2008). Moreover, Miyamaru et al. (2012) reported that the
carbon and nitrogen contents of soil microbial biomass
significantly increased after the application of organic matter, which increased the level of soil available nitrogen in
upland soils. Furthermore, the application of cane molasses,
a byproduct of sugarcane production, also increased the
levels of soil available nitrogen and improved the sugarcane
yield by 20–30% (Yoshida et al. 2017). It was suggested that
easily decomposable organic matter such as sucrose in
molasses increased the amount of microbial biomass and as a
result increased the level of soil available nitrogen.
The destruction of the hardpan layer is generally performed by subsoiling. Additionally, it is reported that
subsoiling increases sugarcane yield by 12% (Oshiro and
Hamakawa 1980). It has also been noted that subsoiling
improves the soil water-holding capacity and drainage
conditions as well as softening the soil (Onaga and Gibo
1984; Shinzato et al. 2013). Sugarcane is a deep-rooted
crop and the effect of irrigation on the yield is therefore
high, although in some cases negative effects on sugarcane
growth are seen due to poor drainage. Therefore, subsoiling
is suitable as a soil management method for sugarcane
fields.
10.3.8 Globally Important Agricultural Heritage
Systems
The modern agricultural system has succeeded in supplying
food for a growing population but has also resulted in
environmental problems such deforestation, water pollution,
climate change, and so on throughout the globe, causing the
extinction of unique local cultures and the destruction of
landscapes and biodiversity. Nevertheless, it is evident that
in many parts of the world, unique systems of agriculture
have been maintained. Traditional agriculture, including
knowledge systems, adapted technologies, landscapes, and
biodiversity, continues to be protected from the adverse
effects of modernization.
The Food and Agriculture Organization of the United
Nations (FAO) is designating certain areas as globally
important agricultural heritage systems (GIAHS) in order to
maintain and preserve such agricultural systems in an integrated manner for the next generation. GIAHS are defined as
“remarkable land use systems and landscapes which are rich
in globally significant biological diversity evolving from the
co-adaptation of a community with its environment and
needs and aspirations for sustainable development” (FAO
2002).
As of 2018, 50 sites in 20 countries in the world, 11 of
which are in Japan, had been designated as GIAHS. Three
sites have been designated in Kyushu: the Aso Grasslands,
the
Kunisaki
Peninsula
Usa
area,
and
the
Takachihogo-Shiibayama area. The following subsections
introduce the soil management in these sustainable agricultural systems.
(1) The Aso Grasslands
The Aso Grasslands in Kumamoto prefecture, located in
central Kyushu, is the largest grassland area in Japan, covering about 220 km
2 (Miyabuchi and Sugiyama 2008). The
Aso Grasslands are a secondary (or semi-natural) grassland
composed mostly of Miscanthus (Japanese pampas grass),
Pleioblastus (warm temperate dwarf bamboo), and Zoysia
(Miyabuchi and Sugiyama 2016). The Aso Grasslands
continue under the balance of receiving artificial disturbance
and natural reformation. Since the Aso Grasslands are connected with both livestock rearing and local farming through
the use of the biomass of the grasslands as green manure and
348
Y. Arakawa et al.