Nasunohara - Nasunohara

It refers to the area north of the center of the spindle-shaped Nasu Alluvial Fan, sandwiched between the Naka River and the Houki River in northern Tochigi Prefecture. The alluvial fan is about 600 meters above sea level in the northwest, and the further southeast you go the thinner the gravel layer becomes and the shallower the groundwater becomes. In the center there are three rows of hills made of lower Quaternary System and loam layers, and the Sabi River and Kumagawa River run across the alluvial fan, becoming surface flows at the apex and ends and underground flows in the center. The apex and center of the fan in the northwest of the Nasu Alluvial Fan are called Nasu Plains, and most of it belongs to Nasu-Shiobara City. Near the apex, there is little water, the topsoil is thin and acidic and infertile, the climate is cool, and there are large areas of forest and wilderness, so it was considered barren and development was delayed. Development of Ogio began in 1647 (Shoho 4), but was unsuccessful. In 1885 (Meiji 18), the Nasu Canal was opened through the efforts of Innami Josaku, Yaita Takeshi, and others, and full-scale development was carried out, with many large farms being built. Until World War II, tobacco, upland rice, buckwheat, and other crops that are resistant to acidic soil were cultivated in the fields of Ogio, and horses were raised. After the war, the large farms were dismantled as part of the agricultural land reform, and many collective settlements were created, mainly in the northern part of the area, with dairy farming at the core. Farmland, forests, and wilderness areas were opened up through the use of electric pumping and the Nasu Canal, and the area became one of the prefecture's four major rice-growing areas. Tobacco cultivation declined. Large-scale agricultural land development projects were carried out to promote the development of the Nasu Plains, and irrigation canals such as the Nasu Canal were extensively renovated. Furthermore, since 1960, large factories have been established mainly in Kuroiso City (now Nasushiobara City) and Otawara City, and the JR Tohoku Main Line, Tohoku Shinkansen, National Route 4, and Tohoku Expressway run through Ogino from the southwest to the northeast.

[Hisashi Okuda]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

栃木県北部、那珂川(なかがわ)と箒川(ほうきがわ)とに挟まれた紡錘状の那須扇状地の扇央以北をいう。扇状地の標高は北西部で約600メートル、南東に行くほど砂礫(されき)層が薄くなり、地下水も浅くなる。中央に第四系下部とローム層からなる丘陵が3列あり、蛇尾(さび)川、熊川が扇状地を縦断し、扇頂・扇端で地表流、扇央で伏流になる。那須扇状地の北西部にあたる扇頂・扇央の部分が那須野原とよばれ、大部分は那須塩原市に属する。扇頂付近では水が少なく、表土は薄く土壌は酸性でやせ、気候は冷涼で、森林、原野が広いため不毛地とされ開拓は遅れた。扇央の開拓は1647年（正保4）以来行われたが成功せず、1885年（明治18）に、印南丈作(いんなみじょうさく)や矢板武(やいたたけし)らの努力で那須疏水(そすい)が通じ、本格的に開発され、多くの大農場が造成された。第二次世界大戦前まで扇央の畑ではタバコ、陸稲、ソバなど酸性土壌に強い作物の栽培が行われ、馬が飼育されていた。戦後、農地改革で大農場は解体し、北部を中心に多くの集団開拓地がつくられ、酪農中心の農業が行われている。電力揚水、那須疏水によって畑地、森林、原野は開田され、県の四大稲作地の一つとなった。タバコ栽培は減少した。那須野原の開発を進めるため大規模農地開発事業が行われ、那須疏水などの用水は大改修された。また1960年（昭和35）以来、黒磯市（現、那須塩原市）、大田原(おおたわら)市を中心に大工場が進出し、JR東北本線、東北新幹線、国道4号、東北自動車道などが扇央を南西―北東に通じている。

［奥田　久］

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