Optimal Rice Planting Date Map

Climate change impacts

In recent years, deterioration in the quality of pre-milled rice caused by the frequent occurrence of abnormally warm temperatures has become a nationwide problem . A weather sensitivity study in Hyōgo Prefecture, in which non-climate factors affecting cultivation were adjusted to allow the observation of the effects of global warming, shows that after 1998 the flowering (when the rice ear emerges) and harvesting of the Yamada-Nishiki rice variety has speeded up, while the number of stalks and ears have increased, leading to a decline in quality. Average temperatures in the period between flowering and harvesting (ripening period) from 1998 to 2008 has increased by 2°C compared to 1987 to 1997.

Adaptation activity

Delaying when rice is sown can be an effective countermeasure to rising temperatures during the ripening season. The Optimal Yamada Nishiki Planting Date Calculator System was therefore developed in 2013, which can indicate the best time to plant rice for individual fields. An online "Planting Date Map" is now available free of charge, allowing rice farmers to check the rice-planting schedule.

Details appear in Local Adaptation Interview.