Recent Expansion and Future Perspectives of Direct Rice Seeding in Miyagi Prefecture of Japan

Abstract

In Asia, the most common method of planting rice is transplanting seedlings, but there is a gradual and progressive shift to direct seeding. In Japan, recent socioeconomic factors and the population trends of aging and migration to urban centers, have led to a decrease in labor which has forced many rice farmers to utilize direct rice seeding in their fields so that they can manage larger fields with less labor. We investigated the expansion of direct seeding in Miyagi Prefecture in the Tohoku region of Japan and discussed the technology that led farmers to accept the direct seeding methods. An early and critical turning point was the Great East Japan Earthquake of 2011, which required the reconstruction of paddy fields and farmers’ associations after the earthquake and the resultant highly destructive tsunami. The direct seeding area in Miyagi Prefecture occupied 1.5% of the rice planting area in 2011 just before the earthquake. The direct seeding area increased to 6.9% as of 2023. The wet seeding method of direct seeding was applied during the initial expansion stage because thermal retention by flood waters was necessary. However, one of the major constraints of wet seeding is low germination, which has led to the technological development of enhanced seeding methods. In particular, coatings applied to the seeds and specifically the iron coating used in wet seeding contributed to the initial expansion of direct seeding. The more recent expansion of direct seeding is being driven by the dry seeding method. Dry seeding in early spring was established to obtain relatively stable germination. This early spring seeding provides farmers with less work conflict in the spring. Since weeds are a common problem in direct seeding methods, technological improvement in weed management with herbicides has also contributed to this expansion. However, the expectation of high-quality rice with organic weed management requires the future development of nonchemical management strategies. Despite the socioeconomic and population changes and the technological improvements related to direct seeding, direct seeding currently accounts for only 6.9% of the total rice seeding and planting across Japan. The rice quality and recommendations and preferences of consumers as well as the price of rice, continue to be key factors determining transplanting versus direct seeding. Additional research, both technical and consumer-related, is indicated to understand and influence future trends in rice transplantation and direct seeding.