In the High Plains regions of the United States, once called the Great American Desert, productive farming regions were formed due to the introduction of center pivot irrigation systems since the 1960s. Finney county of Southwest Kansas, our study area, is one of the most productive farming regions in the High Plains, where irrigation has a long history. While windmills were built to take advantage of shallow ground water in the late nineteenth century, surface water became diverted from the Arkansas River by constructing irrigtion ditches beginning in the 1880s. Ditch irrigation was further promoted by the construction of sugar factory in Garden City in 1906 and the subsequent sugar beet cultivation mainly on the High Plains tablelands of the left bank of the Arkansas. On the other hand, introduction of turbine pumps and the use of inexpensive natural gas pumped from the underlying Hugoton gas field combined to promote the development of ground water irrigation from the 1940s.
The most striking in the history of the High Plains is the invention and introduction of the center pivot irrigation system. The Gigots introduced a valley brand system of center pivot irrigation in 1963 in order to improve their farmland in the sandhill, and their success triggered the application of the new irrigation technology. The early 1970s were boom years in Garden City and its vicinity when the Gigot Irrigation soled 600 systems annually. The sandhills on the right bank of the Arkansas, where rolling topography, infertile soils, and excessive drainage defied intensive use of land and therefore remained the barrens, were most efectively transformed into the landscape dominated by big circles. On the left bank, center pivot systems were introduced in the dry land farming districts on the talbelands, while they are gradually replacing traditional ditch and groundwater irrigation. Such a transformation process is well documented by the distribution of wells and the aerial photo analyses. Due to these irrigation developments, production of feed crops expanded such as maize, alfalfa, sorghum, and soy beans.
The development of irrigation and feed crop production is key to understand the subsequent phases of regional changes, including feedlot and beef packing industries, population composition and dynamics, and undergroud water management. It is necessary to closely examine these geographic features in order to understand the sustainability of the High Plains regions.

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　本論文は南北アメリカ地誌を文化地理学の視点と方法で検討する試論であり，新大陸と呼ばれてきた広大な地域を考察するための枠組みを提示することを目的とする。アメリカ合衆国における地理学の研究動向および南北アメリカを対象とした文化地理学研究の成果を概観し，4つの研究のアプローチ，すなわち人間と環境，起源と伝播，地域と景観，時間と変化が重要であることを指摘した。このような認識に基づいて，コロンブス以降の南北アメリカを概観するために，北西ヨーロッパ系小農経済文化地域，プランテーション経済文化地域，イベリア系牧畜経済文化地域の設定を試みた。そして，アメリカ合衆国の発展は北西ヨーロッパ系小農経済文化地域が国土の全域に拡大するプロセスであることを指摘するとともに，具体例としてグレートプレーンズ，南カリフォルニア，カリフォルニア・セントラルバレーにおける地域変化の概要を示した。さらに，3つの経済文化地域の設定は南北アメリカにおける日系社会の比較研究に有効であることを論じた。

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