Dry fields - Kanden

Paddy fields are classified as dry, semi-damp, or wet depending on the quality of drainage. Dry rice fields are those with a low groundwater level and good drainage, where the surface of the paddy field is always dry during non-irrigation periods except immediately after snowmelt or rainfall, and where water never seeps out when you step on the paddy field. The productivity of rice is stable and high, and it is easy to mechanize and grow wheat and other crops in the second crop, making it suitable for intensive use of paddy fields, so wet and semi-damp fields are also being converted to dry. However, the introduction of heavy machinery has formed a compacted layer under the topsoil, and as a result, the number of wet fields is increasing.

[Yuki Koyama]

"History of Agricultural Technology in Japan - From Early Modern to Modern Times" by Oka Mitsuo (1988, Minerva Shobo) " "The Management Benefits and Conditions for Establishment of Direct Seeding of Rice" by Komuro Shigeo (1999, Agriculture and Forestry Statistics Association) " "Development of Agricultural Technology and Management" by Yoshida Hideo (2002, Agriculture and Forestry Statistics Association)"

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

水田は排水状態（水はけぐあい）の良否によって乾田、半湿田、湿田に分けられるが、乾田とは地下水位が低く排水の良好な水田のことで、融雪あるいは降水直後を除く非灌漑(かんがい)期間に田面がつねに乾燥し、足を踏み入れても絶対に水がにじみ出ることのない水田をいう。水稲の生産力は安定して高く、機械化や麦などの裏作もしやすく、水田の高度利用にも適しているので、湿田、半湿田も乾田化が進んでいる。しかし重量機械の導入により作土下に圧密層が形成され、これによる湿田が増加している。

［小山雄生］

『岡光夫著『日本農業技術史――近世から近代へ』（1988・ミネルヴァ書房）』▽『小室重雄編著『水稲直播の経営的効果と定着条件』（1999・農林統計協会）』▽『吉田英雄著『農業技術と経営の発展』（2002・農林統計協会）』

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