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…The proportion of rice fields that are always barren is relatively small, although there are regional variations. “Yoshiarashi” refers to rice fields that have been abandoned for a certain period of time due to various conditions such as a decline in soil fertility, inadequate irrigation water, and labor mobility, and was also called “kataarashi.” Before the first half of the 12th century, these rice fields amounted to 30-50% of the cultivated land area on average, and some were left uncultivated for as long as 10 years. …

*Some of the terminology explanations that refer to "Kata Arashi" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…田畠全体に占める常荒の割合は，地域的偏差はあるが比較的小さい。年荒は，地力の減退，灌漑用水の不備，労働人口の移動性などの諸条件により，ある期間耕作を放棄した田畠をいい，〈かたあらし〉とも称した。この田畠は，12世紀前半以前では，平均すれば耕地面積の30～50％にも達し，長いものは10年余りも耕作されなかった。…

※「かたあらし」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報