Japanese Journal of Soil Science and Plant Nutrition

Show abstractHide abstract

Since the market price of fish is variable by different fish kinds as well as according to the amount of catch, various kinds of fish are used for the manufacture of fish-scrap, and cases of falsification, especially of the used fish kinds, are often met with. And accordingly the judgement of the quality of fish-scrap is not an easy task. It has been mostly done by one's experience and no scientific method has been used. At first hand, the identification of the fish kinds used for the fish-scrap is much desired, and for that purpose the present study is attempted. The method to get easy means for the said identification is as follows : I. Identification by bones. Pieces of bones found in the fish-scrap are compared morphologically to those obtained from known fishes which may usually be made into the fish-scrap. Chief bones, such as, dentary, opercle, vertebra, etc, are the ones most available for the purpose, and by that comparison fish kinds used as the material of fish-scrap are able to identify with certainty. Proteolytic enzyme is very useful for the extraction of bones from the fish-scrap. (Figs. 12,13) X-ray photographs are also available for the comparison of bones, as they show clearly the special features for each fish-kind. (Figs. 15-21) II. Identification by scales. Scales of fish found in the fish-scrap is available, as they show special characters for each fish kind by their type, shape, radii, circuli, colour and speckles. (Figs. 22-24) With regard to the fish-meal which is powdered and contains no bones and scales in their natural shape, great difficulty is met with, as morphological and X-ray examinations are not applicable. In such case I think it best to rely upon the serological study, which is now in progress.

View full abstract

Download PDF (13169K)

Seasonal changes of pH values in the tea garden soils in Uji district, where the poor tea garden soils are distributed, were investigated during from june 1935 to nobember 1937. The results are summarized as follows : 1) The pH value of tea garden soil was generally varied with the season. During summer and early autumn, the pH value was usually lower, mostly about 4,and the fluctuations were not remarkable. On the other hand, during late autumn and spring it was higher with a considerable variation and mostly was about 5 to 7 and over, and this increase and variation of the pH value may be chiefly due to the manuring of much nitrogenous organic fertilizer in the season. 2) The fluctuations are connected with rainfall, by which pH is generally increased. The absorption of nutrient by tea plant and microbial activity also seem to have some influence on the fluctuation. 3) The maximum changes were from 1.12 to 3.72 in pH unit during from june 1935 to may 1536,from 1.90 to 3.81 during from june 1936 to may 1937 in the manured field, and from 1.42 to 1.49 during from december 1936 to november 1937 in the unmanured. 4) The pH value of the poor soil was slightly lower than that of the good soil during summer and early autumn, while during late autumn and spring, it was higher, and therefore the fluctuation through year was greater in the poor soil. 5) Above lower and higher pH values frequently found in the tea garden soil, may be unfavorable for the tea plant growth and it might be one of the causes which make tea garden soils so low productivity.

View full abstract

The author studied the change of oxidation-reduction potential of both paddy and dry field soils which were dressed with various nitrogenous manures. The results are summarized as follows : 1. Paddy field soil. Potential dropped markedly in the first stage and Eh attained to the lowest value after 2-7 weeks, and then it increased gradually to initial value. Plots of organic manures, especially of Genge (Astragalus sinicus) and of sardine cake, showed much lower value than the others, and those of ammonium sulphate and of no manure, much higher value. Subsoil (about 15cm depth) showed also the same tendency, but had somewhat higher Eh value and later Eh drop than surface soil. 2. Dry field soil. Potential dropped slightly in the early stage. But no marked difference was found among plots with the exception of calcium cyanamide plot, which showed lower value throughout the experiment. The above was true with subsoil potential. It was also experimented that lower Eh value of calcium cyanamide plot was partly due to higher pH value of the plot.

View full abstract

In the previous paper, it has been reported that the nitrate-reduction in paddy field soil is closely related with the formation of ferrous iron in soil. In this paper, the author conducted several experiments on the nitrate-reduction in the soil stood previously with water before nitrate-addition and the results obtained will be summarized as follows; 1) The amount of reduction was remarkably decreased by standing soil with water before nitrate-addition. (with both dry and paddy field soils) 2) The reduction of nitrate was fairly increased by stirring soil before nitrate-addition. 3) The potential of soil kept under stagnation previously before nitrate-addition was not entirely lowered farther, but increased gradually. 4) The % of the reduced nitrogen was greater, the smaller the quantity of nitrate applied and its actual amount was smallest in 2mg plat and was almost same with cases of 5 and 10mg. 5) The reduction of nitrate was markedly decreased in acid condition and at pH 5 and 2 weeks previous standing, this decrease was from 20.4% to 63.0%

View full abstract

Register with J-STAGE for free!