Studies on the Soft-Textured Rice Kernel : IX. Giving nitrogen as fertilizer and formation of soft-textured rice kernel

[摘要] We made our pot experiments with Norin No. 1 in the years 1955-56 on the use of nitrogen as basic and additional fertilizer in the following three plots established for this specific purpose: (1) A plot under standard fertilization, established in 1955 (3 g of ammonium sulfate for basic fertilizer given on May 31, and for additional fertilizer 0.6 g of the same given on June 16 (in the tillering stage) and 0.4 g of given on July 2 (in the ear-forming stage), (2) a plot with the total amount of basic fertilizer (given on May 31), and (3) a plot with the total amount of additional fertilizer (2 g of ammonium sulfate given on June 16, 1 g of the same on June 23, and 1 g of the same on July 5). In 1956, the experiment was carried out with nearly the same method as in 1955. Our quantitative analysis of standard unpolished rice grains produced in the above-stated plots showed no difference in the result constantly was the soft-textured property of rice kernel in constituent ratio. In order to compare with our standard fertilization plot, we established another plot where we used urea spraying it on the foliage, once everyday, from the heading till the ripening date. Our experiment on the spraying of urea on foliage was made in 1959 in the testing rice field of the University of Fukui to examine the formation of hard-textured rice kernel. In this experiment, Norin No. 1 was grown under standard culture in standard, plenty or no fertilizer plots, the first date of ear-sprouting being July 23 and the ripening date August 28 for the plot provided with standard amount of fertilizer. During this period, we gave foliage spray of urea on the surface once at 10 a. m. everyday, thirty times in total. In three other plots we gave spraying 1, 5, and 10 times each, continuously after July 23, and studied the constituents of standard unpolished rice grains thus produced. In this test we put 15cc of 1 % aqua solution (pH 5.7 applied as sticker) per hill under 2 block system of 16 hills in each plot. The results of analysis of all the materials thus examined showed some difference in [○!P] and [○!T] among the different plots with increase in [○!T] as well as [○!P], thus producing semi-hard-textured rice kernel, but no formation of hard-textured rice kernel was observed in any plot where we made our experiments. In Osaka, too, in 1959 there was carried out almost the same experiment as in Fukui, and the result was only the semi-hard-textured rice kernel and the formation of soft-textured rice kernel could not be found in any experimental plot contrary.

[学科分类] 农业科学（综合）