2025 Volume 94 Issue 2 Pages 177-188
We examined the applicability of the values of vegetative coverage ratio, obtained by a smart-phone application for diagnosing the amount of ear fertilizer applied, as one of the growth diagnostic indicators of the Sake rice variety, Yamadanishiki. Utilizing statistical methods, we compared the values of the vegetative coverage ratio (our proposing labor-saving method) with those of the growth index value (one of the traditional labor-intensive methods) on the panicle formation stage. The study was conducted in six cropping seasons during the three years from 2017 to 2019, with four levels of base fertilizer applied at different transplanting periods. The values for all investigation items were higher with the increase in fertilizer application. We found differences amongst cropping periods, except for the values of the above-ground nitrogen content. There was a positive correlation between the values of vegetative coverage ratio and those of the above-ground nitrogen content, as well as those of the growth index value. Furthermore, a positive strong correlation existed between the values of the vegetative coverage ratio and the growth index value. In summary, we conclude that the vegetative coverage ratio is an efficient and promising growth index, as an indicator for the growth diagnosis of Yamadanishiki.
