2022 Volume 91 Issue 3 Pages 239-245
The grain ash content is problematically high in the wheat variety ‘Yukichikara’ for bread cultivated in the sand dune in Niigata city. We examined the farmer’s fields of ‘Yukichikara’ for four cropping seasons in the sand dune to clarify the actual state of grain ash content and the conditions leading to the increase in grain ash content. The grain ash content was not affected by the available phosphoric acid in the sand dune soil. The grain protein content was correlated to the grain ash content in the 2016, 2017 and 2019 cropping seasons, but not in the 2018 cropping season. The thousand grain weight was increased by nitrogen topdressing at flowering in the 2018 cropping season, and the increase of grain ash was relatively smaller than the increase of grain ash in the other three cropping seasons. The soil matric potential in the ripening period decreased to about -100 kPa in the 2018 cropping season, but it was about –1000 kPa in the other three cropping seasons. Soil water deficiency occurred during the ripening period except in the 2018 cropping season. These results suggested that soil water deficiency during the ripening period suppressed the increase in thousand grain weight in response to nitrogen topdressing at flowering, and resulted in an increase in the grain ash content.
