Abstract
This study investigated the effects of puddling and drainage on seedling emergence and establishment of rice direct seeded with a “shooting hill-seeder” in submerged paddy fields. Water content (oxygen diffusion rate) of puddled soil was higher (lower) in the plots where puddling was conducted twice with a paddy harrow than in the plots puddled only once. Water content and the oxygen diffusion rate of puddled soil varied somewhat with the degree of drainage after sowing even within the same plot due to irregular leveling there. The water content (oxygen diffusion rate) of soil was lower (higher) in the well-drained part than in the poorly drained part. The number of established rice seedlings per square meter in the twice-puddled plot was lower than that in the once-puddled plot. The number of established rice seedlings per square meter was the lowest in the poorly drained part of the once-puddled plot, and seedling growth there was the worst. These suggest that in rice seeding with a shooting hill-seeder followed by drainage less puddling (avoiding over-puddling) and proper draining with uniform leveling are necessary for both stable seedling emergence and establishment.
