Page 187 - Changing Living Spaces

Structural Changes in Fertilizer Circulation in Modern Japan

od. In 1910, the Waste Cleaning Law was revised, and the administration
became actively involved in waste disposal, with the handling of human
waste entrusted to prefectural governors.
In major cities such as Tokyo, Osaka, and Nagoya, the need for munic-
ipal management of sewage treatment increased since the 1900s in or-
der to secure financial resources for water supply and sanitation. Nagoya,
in particular, is said to have pushed for municipalization of wastewater
treatment more out of financial necessity than for public health reasons.
According to a survey conducted by the Nagoya City Sanitation
Division, in July 1921 the daily excreta volume of the entire city was about
700,000 litres, of which about 150,000 litres was excess human waste that
could not be treated. In addition, as urbanization took place, land former-
ly used for agriculture was converted to housing or factory use, and rural
areas were moved to the outskirts of the city. As cities grew, transporta-
tion costs increased, more human waste was retained in cities, and dis-
posal became a major social problem.
Under these circumstances, it became necessary to increase govern-
ment involvement in sewage treatment. In 1930, the Waste Cleaning Law
was amended to include human waste, which had previously been exclud-
ed from it. This was a problem not only in Nagoya but also in other parts
of Japan.

Conclusions: Stepwise Reconstruction of the Material Cycle
This study illustrates the structural changes in the material cycle of mod-
ern Japanese agriculture by focusing on the changes in fertilizer technol-
ogy in Aichi Prefecture in the early twentieth century. In particular, we
examined the conflict between the use of night soil and the processing of
human waste from both rural and urban perspectives. With regard to the
return of human waste to farmland, i.e. its use as night soil as a single
material cycle, a decline has been observed in the modern era.
This study concludes that it is not a decline but a gradual reconstruction
of the material cycle. This is because, as we have seen, the use of night soil
continued to coexist with the processing of human waste. Subsequently,
night soil continued to be used as a self-sufficient fertilizer during and
after World War II due to the shortage of materials. Therefore, the use of
night soil continued in Japan at least until the 1960s.
When it comes to the restructuring of the material cycle in mod-
ern times, rapid urbanization and population growth are both impor-
tant events. The rapid increase in population resulted in a massive ex-

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