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Irrigation is a widespread practice required in many areas of Australia, the driest inhabited continent, to supplement low rainfall with water from other sources to assist in growing crops and pasture.〔(【引用サイトリンク】 Living with drought )〕 Overuse or poor management of irrigation is held responsible by some for environmental problems such as soil salinity and loss of habitat for native flora and fauna.〔 〕 Irrigation differs from dryland farming (farming relying on rainfall) in Australia in its level of intensity and production. Common crops produced using irrigation include rice, cotton, canola, sugar, various fruits and other tree crops and pasture, hay and grain for use in beef and dairy production. Surface irrigation is the most common irrigation method in Australia, with drip and center pivot also utilised. All rights to use and control water are vested in the state, which issues conditional entitlements for water use. The first large-scale irrigation schemes in Australia were introduced during the 1880s, partially in response to drought. In 1915 the River Murray Waters Agreement was signed, setting out basic conditions for the river's water use which remain in force today. Towards the end of the 20th century, environmental problems in the basin became serious as diversions for irrigation approached or exceeded the capacity of natural flows. Following negotiations beginning in 1985, the Murray–Darling Basin Agreement was signed in 1987. The more comprehensive National Water Initiative was adopted in 2004. ==Water sources== In general, water for irrigation comes from two main sources, river systems and underground aquifers. Major river systems used for irrigation in Australia include the Murray-Darling system, the Ord River in the Kimberley region of Western Australia and many rivers along the east coast of Australia. This includes the Burdekin River Irrigation Area in North Queensland where irrigation is used during the dry season for double-cropping.〔(【引用サイトリンク】title=Burdekin Haughton )〕 A major source of ground water in Australia is the Great Artesian Basin. Although the Murray-Darling Basin receives only 6% of Australia's annual rainfall, over 70% of Australia's irrigation resources are concentrated there, which makes up around 90% of the resources in the basin. It contains 42% of the nation's farmland and produces 40% of the nation's food. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Irrigation in Australia」の詳細全文を読む スポンサード リンク
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