Soil-Forming Factors

Because the current climate zone of Japan ranges from subtropical to subarctic, soil temperature regime also varies from hyperthermic to frigid. The annual precipitation ranges from less than 1000 to over 2500 mm. The Pleistocene climate also affected the development of soils of Japan through formation and deposition of soil parent materials. The outline of the landforms has mainly been formed by the subduction of the tectonic plates in the vicinity, leading to a long and complicated history of the geology. The Japanese Islands constitute the most prominent volcanic area in the world with more than 111 active volcanoes. The plains are divided into the coastal plains and the inland mountain basin. A wide range of wind-blown dust, including Kosa, has been added to various sediments. The vegetation is characterized by a large number of species and a high percentage of endemic species due to a large variation in landscape, geology and climate. The majority of mountainous, hilly and volcanic areas are covered with forests. Most agricultural lands in cities situated in flat areas and suburban alluvial lowlands are mainly used for paddy fields, and higher terraces are used for upland cultivation.