The historical-geographical study of the relationship between the regional difference of cotton growing and the coditon of irrigation in Nara basin in Edo period.

据了解，奈良盆地的棉花种植是在稻田进行的，经历了几次衰退。但这样的下降并不是在奈良盆地统一发生的。为什么会出现这种地区差异？本研究旨在从灌溉条件的角度来阐明这种区域差异。在本研究中，我找到了奈良盆地许多村庄的棉花种植比率，并对其区域差异进行了研究。结果表明，稻田棉花种植比例以岛州县东知县最高，速崎县山部县较高。其次，将棉花种植转型分为以下四种类型。第一种类型是江户时代早期水田棉花生长衰退。原因是认为这些地区有丰富的灌溉条件，可以改种棉花为水稻。第二种类型是江户末期棉花生长衰退。在这些地区，他们修建了新的池塘或修复了旧池塘，从而改变了灌溉条件。第三种类型是江户晚期棉花生长进入活跃时期。在该类型中，除江户晚期地震对池塘的破坏影响外，棉花生长与灌溉条件无关。第三种类型是江户时期保持相同的棉花种植比例。在江户时代，这一类型的灌溉没有得到改善。推测奈良盆地棉花种植的区域差异与池塘灌溉条件有关。

It is known that the cotton growing in Nara basin was performed in paddy field and it declined by several affairs. But such decline didn't occur uniformly in Nara basin. Why such regional diffrence occured? This study aims to make clear such regional diffrence from the point of the condition of irrigation.In this study I found the ratio of cotton growing of many villages in Nara basin and studied the regional diffrence. It was found that the ratio of cotton growing in paddy field was the highest in Toichi, Shikijou county, higher in Yamabe, Soekaki county. Secondly I divided into four types of transition of cotton growing as following. The first type is that cotton growing in paddy field declined in early time in Edo period. The reason is thought that these area was rich on condition of irrigation so that they could change cotton to rice growing. The second type is that cotton growing declined at end of Edo period. in these area they constructed new pond or repaired old pond and by doing it hte condion of irrigation changed for the better. The third type is that cotton growing became active tempolary in the late Edo period. In this type there were no relationship between cotton growing and irrigation condition except for the influence of the destroy of pond bank by the earthquake in the late Edo period. The last type is that the same ratio of cotton growing was kept in Edo period. In this type the improvement of irrigation was not done in Edo period. It is guessed that the regional difference of cotton growing in Nara basin has some relationships with the condition of pond irrigation.