Studies on the Settling of Transplanted Rice Seedlings.

In the previous findings by the authors, it was shown that the settling ability of lowland nursery seedlings was generally lower than that of upland ones both in early and late transplanting cultures of rice plants. More detailed studies were made on the aspect by the same authors. Rice varieties used for the experiments were; 1) cold resistant varieties, 2) cold region varieties, 3) hot region varieties and 4) growth habit hybrids. And of some of the varieties, the seedlings were dressed with much silicic fertilizers. It was elucidated that, in early transplanting culture of rice plants, being naturally attended by low temperature conditions, the settling of upland nursery seedlings was found generally better than that of irrigated seedlings even in the case when the varieties were of the "hot-region" type. In late transplanting culture, application of abundant silica to the nursery bed was found effective to some extent for prevention of withering of leaf blade, but it did not bring any increase in the weight of dry matter of seedlings in the lowland nursery bed. The delay in the seedling settling at cold regions or at cold water districts and low temperature injuries in rice culture would be considerably prevented by means of early transplanting with upland nursery seedlings.