沖縄県におけるウコンの植付時期が、出芽、生育および収量に及ぼす影響

Abstract

The present study was conducted to evaluate the effects of the temperature and planting date (month) on the emergence, growth and yield of turmeric {Curcuma longa L.) plats in Okinawa Prefecture, Southern Japan. Turmeric rhizomes were planted on February 15, March 15, April 15, May 15 and June 15 as treatments for the planting date. Temperature range of 25-35 °C was optimum for the sprouting of turmeric rhizome-buds, and sprouting did not occur below 10 °C or above 40 °C. Seedlings elongated well in the temperature range between 25 and 30 C, but could not survive at above 40 C. The emergence of the turmeric seedlings in the February, March and April plantings started at nearly the same time, and was completed within June. Shoots of turmeric plants differing in the planting month started to wither at the same time in November, and completely withered in January. Shoot dry weight and yield of turmeric plants were significantly higher in the February planting followed by the March and April plantings than in late planting in the glasshouse experiment, whereas in the field experiment the values of these two parameters were significantly higher in the April planting followed by the March and February plantings than in the late planting. The fields of the turmeric plants in the February and March plantings required additional weeding before emergence because winter and spring weeds emerged earlier and grew vigorously. The order of total weed dry weight was as follows: February planting> March planting >April planting >May planting >June planting. The emergence pattern, growth and yield of turmeric plants, and weed growth in the field experiment suggested that turmeric should be planted in April followed by March in Okinawa, Japan.