Studies on the Soft-Textured Rice Kernel : VIII. Kinds of soil texture and the three essential elements of fertilizer in the formation of soft-textured rice kernel

Abstract

In our experiment of 1958 we cultivated Norin. No. 1 in the testing farm of the University of Fukui under our standard method of cultivation. We used a/5, 000 Wagner pots (placing 10 pots in each plot) and experimented with three kinds of soil for cultivation : 1) cultivated soil (clay loam) from the paddy-field of our farm, 2) refined heavy clay (dia. less than 0.01mm), and 3) sandy soil (coarse sand with dia. 2.0-0.2mm.) from the river bed. As basic fertilizer we gave on May 20 3 g of ammonium sulfate, 4 g of calcium superphosphate, and 1.4 g of potassium chloride per pot. Transplanting the seedlings under standard culture (50-day seedlings aged 6.5 leaves, 3 seedlings per hill per pot) on May 21, we then proceeded to give them additional fertilizer, 0.6 g of ammonium sulfate on June (in the tillering stage) and 0.4 g of the same on July 1 (in the early ear-forming stage). Thus our experiment was fed by conducted under our standard cultivation with the use of three elements of fertilizer above-stated, fed by the water of our city aqueduct. Further, in order to produce rice grain, we applied half of the whole volume of fertilizer on those plots with sandy soil and heavy clay, where no fertilizer was given. Then collecting the ripe ears in the whole 10 pots of each plot, we selected unpolished rice grains of standard quality, putting them to quantitative analysis. In our experiment of 1959, in the testing rice-fields of the University of Fukui and the Prefectural Agricultural Experimental Branch Station of Osaka (the soil is CL in both places), we used two varieties Norin No.1 and Yutakasenbon to proceed with the same kind of fertilization experiment as before. For each testing field (0.1 a per plot in 2 blocks) we took standard culture as basis (three elements per plot), going through the same process of selection and quantitative analysis. The results of the analysis showed some variations in different pots, but the property of rice kernel in each plot in Fukui proved soft-textured in its constituent ratio, no plot showing a change from soft-textured to hard-textured rice kernel. In Osaka, conversely, no plot showed any change from hard-textured to soft-textured kernel. We conclude from our experiments that the kinds of soil texture and the three elements of fertilizer in the formation of both soft-and hard-textured rice kernel have nothing to do with the varieties of specimens. In other words, we have confirmed that so far as the minimum amount of three elements of fertilizer is present necessary to produce standard rice grains, the texture of rice kernel is free from the influence of any element of fertilizer and any kind of soil texture.