2024 Volume 93 Issue 2 Pages 107-121
To establish the cultivation techniques of early-winter direct-sowing of rice in the Hokuriku region, we evaluated the effects of cultivar, seed production year and seed coating on emergence rate after wintering and yield by mechanical sowing. Five of the six varieties excluding ‘Hokuriku 193’ commonly cultivated in this region were considered to be practical for early-winter direct-sowing cultivation because the emergence rate after wintering by hand sowing was 34 - 68%. We clarified that the emergence rate of seeds produced in the previous year tended to be inferior to that in the current year, and that seed coating with thiuram improved the emergence rate. An early-maturing cultivar ‘Tsukiakari’ which can be harvested early from the viewpoint of preparing the seeds of the current year, was subjected to a mechanical sowing experiment. The seedling establishment rate in simultaneous plowing and sowing was considered to be approximately 25%. As a result, it was estimated that about 11 kg 10 a-1 of seeds produced in the current year would be required for sufficient seedling establishment and yield in this cultivation. Brown rice yield of over 500 kg 10 a-1 was demonstrated through three seasons using ‘Tsukiakari’with the controlled-efficiency nitrogen fertilizers applied to the soil at the time of seeding. This is the first report of early-winter direct-sowing cultivation in the Hokuriku region, and provide basic knowledge for systematically establishing this technology.
