オランダのチューリップ球根生産技術の分析

This study deals with technical analysis of tulip bulb cultivated in Holland.
1 . Tulip bulbs were cultivated in Loamy Fine Sand. Cultivated land are sand hills and reclaimed land of sea.
2 . As the climate of Holland is not suitable for the cultivation of tulip bulb, they adopt the method of underground irrigation, protection against the cold and the wind with covering, and of the storage of tulip bulbs under higher temperature than out of door.
3 . The amount of potassium was greater than that of nitrogen and Phosphorous during the growing stage. The remaining amount of potassium was still greater than nitrogen and phosphorous in dead leaves.
4 . Much quantities of three nutritional elements in the soil was shown before the flower time and lower phosphorous and potassium was shown in the soil after the harvet. No difference was found in nitrogen content.
5 . Nitrogen contained in bulbs decreased during the storage period but no change was observed in phosphorous and potassium quantity.
6 . The work cost in hand harvest is equal with small-sized harvest machine per 2,5 ha and with large-sized harvest machine per 4,5 ha.