2004 Volume 73 Issue 3 Pages 253-260
In Gunma Prefecture, rice seedlings are usually grown in nursery boxes kept stacked up by the pool-raising method. In this method, however, the boxes need to be moved several times, which is a laborious task. In the new method, developed in Tochigi Prefecture, seeds are sown in the boxes arranged flatly and seedlings are grown without moving of boxes. However, this technology was developed for use in a green house but not for pool-raising. Hence, we applied this method to the outdoor pool-raising in the normal-season culture of rice in Gunma Prefecture. Covering several kinds of materials delayed of seedling emergence only about 0-3 days. Non covering tended to delay seedling emergence due to the low temperature and drying of covering soil, showing that a covering material was necessary for good emergence. Three kinds of covering materials (Passlight, Kenbyo-sheet and Daiorussell-1600-Black) were excellent. Covering with these materials decreased the even growth, high tempreture and drying of covering soil, and they were able to omit the greening process. Sometimes, the seedling length was increaced and leaf age advanced by the covering, but the final growth of seedlings equalled that in rice grown by the standard method. Therefore, we considered that this method with these covering materials could be useful for sprouting of seedlings emergence in nursery boxes arranged flatly in Gunma Prefecture.
