Writers intended to find a method which determines the most adequate amount of nitrogen to be given to rice plants in a paddy field condition. If we made a graph (for example, as shown in Fig. 4) which shows tne relation between the amount of the grain produced at a given amount of nitrogen and the percentage content of nitrogen in the grain, from which it will be recognized , that there exist two stages. In the first stage the yield of rice grain increases with the increase of the nitrogen supply (from 0 to 50 kg N per Acre), but the nitrogen content of the grain remains comparatively constant (about 1.0%). In the second stage, that is, in the case of heavy dressing (more than 56 kg N per Acre), the yield of grain remarkably decreases, but on the contray, the nitrogen content remarkably increase. So we concluded that the point of inflexion from the first stage to the second denotes the most adequate amount of nitrogen to be given to rice plants in a paddy field condition. Thus, in this research we have obtained, by the recognition of these two stages described above, the following result : a) The highest yield is obtained at the dressing of 50 kg. N per Acre. In this case, the amount of nitrogen in grain is 1.05%. b) But the degree of economic utilization of nitrogen is highest in the case of l7 kg. N per Acre. c) The amount of protein in polished rice is increased according to an increase of the amount of nitrogen given as fertilizer. This increase will be attributed to an increase of NaOH soluble ptotein (Oryzenin).

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The rice plant was cultured in nutrient solutions which have various degrees of the phosphorus concentration (from 0 to 200 p.p.m. P_2O_5) and the following results were obtained. (1) The maximum yield of the rice plant is obtained at the concentration of 20 p.p.m.P_2O_5 in the culture solution. (2) The phosphorus content of the rice plant increases according to the increasing phosphorus concentration in the culture solution. And this tendency is most remarkable at theleaf and stem and less at the root and the least at the ear. 3) There exists the marked interrelationship between the yield and the phosphorus content of the rice plant. Judging from this interrelationship, three stages are distinguished in the condition of the rice plant. Namely, 1st step : in the case of low concentration (under 5 p.p.m. P_2O_5), both the yield and the phosphorus content of the plant increase with the increasing phosphorus concentration in the culture solution. This step may be called "the deficiency stage". 2nd step : in the case of optimum concentration (5-20 p.p.m. P_2O_5), the yield of the plant increases with the icreasing phosphorus concentration in the culture solution, but the phosphorus content in the plant remains comparatively constant. This step may be called "the normal stage". 3rd step : in the case of high concentration (above 20 p.p.m. P_2O_5), the yield of the plant decreases with the increasing phosphorus concentration in the culture solution, but the phosphorus content of the plant increases. This step may be called "the excess stage". (4) The maximum absorption of phosphrus by the rice plant appears when the phosphorus concentration in the culture solution is 150p p.m. P_2O_5. (5) The phosphorus content of the rice plant increases according to the increasing concentration of phosphorus in the culture solution. The increase of phosphorus in the ear is attributed to the increase of phytin in the case of 0-100 p.p.m. P_2O_5 in the culture solution, while in the case of above 100p.p.m.P_2O_5,it is attributed to the increase of inorganic phosphorus. But in the leaf and stem, and the root, it is attributed only to the increase of inorganic phosphorus.

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1) This study was carried out by the authors after the methods of Mr. MARSHALL by meansuring the electric double refraction, mean refractive index and specific gravity of the granules of soil suspensions, and it was found that these methods could be used for studying the minerals of soil clay. 2) There are differences of the minerals of soil clay between allitic soils and siallitic soils.

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1. I have studied on the effects of different amount of phosphorus fertilizer on the contents of phosphorus fertilizer on the contents of phosphorus compound, carbohydrate and nitrogenous compound of tobbaco leaves. 2. With the increased amount of supplid phosphorus fertilizer total phosphorus of tobacco leaves increase, and the main part of increased phosphorus of tobaco leaves exist as in orgaic phosphate, Independent of the amount of supplied phosphorus fertilizer Nuclein-P and Phosphatide-P are nearly constant, but no constant tendency is found in the contents of phosphoprotein-P and Nucleoprotein-P of tobacco leaves. 3. With the increased amount of supplied phosphorus fertilizer the contents of total Nitrogen and Protein of tobbaco leaves decrease, but Sugar and Starch increase. Nicotine contents is almost constant independent of that.

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In reference to the nutrition of some minor elements to the Mulberry tree, we studied on copper content in several soils in Ueda district, and some green leaves which grow up in the farm of the Textile college of Shinshu University.

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The productive efficiency of phosphorus nutrient for the rice plant was estimated by the water culture, which contains different phosphorus concentration in the culture solution. The high efficiencies were shown during the early growth stage, i. e. during 25 days after transplantation of the rice seedings, and in the case of the optimum phosphorus concentrtion, maximum efficiency for grain production was found on about the 16th day after transfer to the water culture.

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In the case of dispersing the so-called volcanic ash soils, the acid reaction of the liquid has been observed to be prefered to the alkaline reaction, which has been hitherto accepted as a suitable reaction for ordinary soils. Of four soils of various parent materials, including of volcanic ash, mechanical analyses were made after British Pipette Method, the soils being dispersed in both reactions acid and alkaline. The acid reaction was obtained by an addition of acetic acid to the extent of pH 4.0 as well as of pH 5.0 the alkaline reaction by ammonium hydroxide in an ordinary way as much as pH 11.0. From the results of analyses, volcanic ash soils were suitably dispersed in the case of the liquid being acidified as much as pH 5.0 by acetic acid (see Table). For the tentative device, especially for the routine work of soil survey, the aforementioned acidification was concluded to be convenient by the authors.

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A strain of Aspergillus niger, which has strong power of forming oxalic acid from carbohydrate, was inoculated to the modified Pfeffer's solution containing rock phosphate as phosphorus source. The mould grew vigorously, and the rock phosphate was decomposed releasing phosphate ion in the culture solution.

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Chemical composition of weeds, in ciuding 61 species of 31 families in Miyazaki Prefec, was studied. Potassium was observed to have an indination of being contained more than phosphoric acid as vellas calcium.

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In this paper it deals with the morphological, mechanical and chemical characteristics of the Red Soils formed over the diluvial deposits of Takashihara and Kano, Pacific Coast of Central Japan (See Tables 1,2 and 3). 1. Main soil formers and profile characteristics of the soils are given in Tables 1 and 2. These soils consist of very thin organic layer (A_0) and slightly dark-coloured surface soils over the reddish orange compact B horizons underlain by grav〓l beds. The lower part of the A horizon does no〓 show any evidence of bleaching. The aggregates of the B horizon do not give a friable consistency, but they are fairly plastic when moist, and hard when dry. 2. According to heavily leaching, the soils are strongly to very strongly acid in reaction, and the degrees of base-saturation range from 20 to 40 percent, except for that of the A_0 layer of Takashihara soil which reaches to about 64 percent. The colloidal clays of them are more allitic than those of the Red Soil of Northern Kyushu and the red earths South China. 3. Exchange reactions (pH in water minus pH in 0.01 n sodium sulphate) of the various horizons show neutrality. From this and other properties it may be considered that these soils are subjected to the anionic solvation and eluviation, and consequently, they are not the products of podzolization.

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In the course of some dynamic studies of the nutrients uptake by crop plants the result of the nutrient uptake of rice crop as influenced by hydrogen sulfide may be summarised as follows : (1) Hydrogen sulfide was bubbled through the water culture solution for about ten minutes in which the root of rice plant was immerced. In one case, the initial pH of the culture solution was controlled to 7.0 and 4.5 respectively. In every case the uptake of NH_4-N and water was depressed seriously, though the effect was always more pronounced for NH_4-N than H_2O (Table 1 (a) (b) and Table 2). (2) The effect of concentration and the period of contact of H_2O-H_2S was studied by rice seedlings. The seedlings were grown in an artificially controlled room (light and temperature) and the effect was conveniently observed through the percent increase of the wilted leaves, which was the definite sign of the reduction in absorption. The injury was enhanced on the prolonged contact or the increased concentration ; the wilting at last appeared in 288 hours even by the extremely dilute concentration of 0.07 ppm as S (Table 3 (a) (b). (3) Hydrogen sulfide was bubbled through the water culture solution as in (1) and the results of the uptake of NH_4N, CaO, SiO_2 MnO, MgO, P_2O_5 and H_2O were tested statisticaliy (Table 4 and Fig. 1). In general, they were highly significant enough to permit definite conclusion. The treatment reduced the uptake in the order P_2O_5>K_2O>SiO_2>Nh_4-N>MnO>H_2O>MgO>CaO. The order of P_2O_5 should be questioned, as it was evident that some P_2O_5 temporarly adhering to the surface of the root as basic phosphated iron could have entered into the solution H_2S treatment. The result was discussed in two ways. Practically, it seems to permit more logical interpretation of the mechanism, why the severe attack of Helminthosporium leaf spot predominates in the poor productive paddy rice field in Japan, where the evolution of hydrogen sulfide is believed to injure the rice root on account of the lack of active iron in the soil (a kind of podsolisation). The relatively strong reduction in absorption in such elements as K_2O, SiO_2,NH_4-N, MnO as compared to H_2O, MgO, CaO concurrs with the several investigations which poit to the high correlation between the deficiency of these elements and the occurrence of the named desease. Theoretically, however, the result must be nothing but the reduction of the "metabolic absorption" as proposed by Hoagland and his associates, on the more or less interruption of which the pure physicochemical characteristic properties of ions, in this case "hydration", might have substantially affected the ion absorption in the order of the well-known lyotropic series. In fact, as for those elements to which the lyotropic series are generally unquestionable the order of the reduction of ion absorption was K_2O>NH_4-N>MgO>CaO.

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It is recognized that the Mn compound in the paddy soil is easily removed from the furrow slice and accumulated in the subsoil, and that the furrow slice of degraded paddy field is poor in active Mn compound as well as in free Fe_2O_3. In the normal paddy field, Mn is observed to be accumulated in the plow-sole while in the degraded paddy field it is accumulated beneath the Fe accumulated layer. The mechanism of translocation of Mn is also disussed.

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In this paper authers investigated the physiological action of field crops, specially with reference to the absorption of plant nutrients. For this experimentt two varieties of barley, Chikurin and Hozoroi, were seleted. Here, the former variety is of the kind required much nutrients and the latter is the one less required in. 〓nutrients. The results of the experiments are summarized as follows. I) In the Chikurin variety the availability of plant nutrients was observed more remarkable than in the Hozoroi variety. And this difference was due to the activities of physiological action of each variety. II) The Chikurin variety showed stronger activity of the plant physiological action, specially in the plant root respiration than the Hozoroi variety. Therefore, it can be said that there exists a inter relationship between the plant root respiration and the nutrient requirement of the plant.

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A simple experiment on the behavior of phosphorus added to the waterlogged soil using radioactive phosphorus P^<32> as a tracer element was carried out. In the case of normal paddy soil, nearly total amount of added phosphorus was fixed by the soil of surface layer, while in the case of degraded paddy soil the added phosphorus was easily leached down. The utilization of radioactive isotope to this kind of experiment is thought to be convenient since it makes it possible to trace the behavior of added element without any troblesome method of identification.

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The ability of Humus and Lignin to prevent phosphate fixation is already recongnized as well as certain organic ions. In this experiment the writers investigated the effectiveness of Humic acids, Hymatomelanic acids, crude humic acids and some of non-humic constituents in preventing phosphate precipitation by iron and aluminum. 1. The results are summerised as follows : The influence of Humic acids, Hymatomelanic acids and crude Humic acids is considerably marked. It seems that the order of the effectiveness is as follows : Citrate>Tartrate>Oxalate>Humate 2. At the same time there are two opposite action among humate, phosphate and iron or aluminium. One is the formation of stable complexes between humate and iron or aluminium, another is the adsorption of phosphate by humus. On account of this fact the amount of phosphate combined in basic phosphates is almost constant, eventhough the among of humus would be increased. 3. The ability to form soluble and stable complexes of Non-humus-constituents with iron or aluminium is similarly smaller than that of humate with iron or aluminium, but Mannit released phosphate completely at the basic range of pH7 to 8.5 and Furfural is very likely to humate in the manner described above.

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