A method to reduce the weight and cost of nursery boxes for paddy rice.

摘要

A trial was conducted in Gunma Prefecture, Japan, to investigate a method, which is reducing the amount of soil in the nursery box, to reduce the whole weight of the nursery box and cost for raising paddy rice seedlings. The depth of covering soil was maintained at 7 mm in all plots, and the depth of base soil was adjusted to 17, 13, 11, 7 and 0 mm. They were compared with the standard depth of 17 mm. Results showed that the 7 mm depth of base soil and even no base soil with 7 mm covering soil were able to raise seedlings having little effect on the accuracy of transplanting. However, in the bed without basing, it raised many seeds over covering soil and also the method of preventing seed-scattering out of nursery box was necessary for sowing. The thin mat was handled carefully. It is suggested that the use of 0 or 7 mm depth basing soil was unpractical. Considering the mat handling and transplanting accuracy, the practical depth of the soil in a nursery box is 18 mm, composed of 11 mm-depth basing soil and 7 mm covering soil. With this method, the weight of the nursery box was reduced to approximately 20% and the cost to approximately 25% compared to the conventional method.