남부평야지 벼 무논 골뿌림 재배시 파종시기가 생육 및 수량에 미치는 영향

The optimum seeding date and the suitable seeding period for puddled drill seeding of rice at southern plain area were determined by using Sinunbongbyeo (early maturing variety), Hwaseongbyeo(medium maturing var.) and Dongjinbyeo (late medium maturing var.) at National Honam Agricultural Experiment Station from 1993 to 1994. Seedling stand was decreased significantly at seeding on April 25 in all varieties. Threshold seeding dates for stable ripening was estimated as June 10 in Sinunbongbyeo, May 31 in Hwaseongbyeo and May 25 in Dongjinbyeo. The 1,000 grain weight and the ripened grain rate were highest at seeding on May 10 or May 25 in all varieties, and decreased significantly at seeding on June 25 in Sinunbongbyeo and seeding after June 10 in Hwaseongbyeo and Dongjinbyeo. The optimum average air temperature for 40 days after heading was 22.6℃ for highest ripening rate and 22.0℃ for heaviest 1,000 grain weight. The optimum seeding date for highest yield was May 9 in Dongjinbyeo, May 13 in Hwaseongbyo and May 15 in Sinunbongbyeo.