Effects of Autumn Direct-seeding on Rice Growth and Yield under Cool Climates

Abstract

Effects of autumn direct-seeding of rice on the growth and yield were examined in Iwate Prefecture, Japan which has a cool climate. Rice seeds coated with four kinds of silicon were sown in October, November and December (autumn) and in April (spring), and the seedling establishment, growth and yield were examined. The percentage of seedling establishment to total seed number in autumn direct-seeding (2 to 6%) was significantly lower than that in spring direct-seeding (89%). The seedling establishment in the autumn direct-seeding did not significantly vary with the time of seeding or silicon coating. The number of seedlings established per m2 was 250 in spring direct-seeding, and 79 in autumn direct-seeding due to about five times higher seeding rates. Thus, the final dry weight and grain yield did not significantly vary with the time of direct-seeding.