Abstract
No-tillage direct seeding of rice (Oryza sativa L.) in early spring was conducted to disperse seeding work and to improve heading time in cold regions. Germinated seeds were seeded every 5 days in 1995 and every 10 days in 1996 from late March to late April. The mean soil temperature at 1 cm beneath the surface (around seeds) during the seedling stage was 4.6°C higher than the mean air temperature in 1995 and 3.7°C higher in 1996 when submerged just after seeding. However, the percentage of seedling establishment of rice by this method was low (14∼47%) in 1995 and (22.8∼38.6%) in 1996. The later the date of sowing, the higher tended to be the rate of establisltment of rice seedling. Sowing in late March hastened the heading time 1∼4 days and increased the leaf number by 0.8∼1.6.
