Authors intended to elucidrate the effects of silica and magnesia for increasing the resistance of rice plant to Imochi disease. In this experiment, three varieties of rice plant, which has very strong, moderate and weak resistance to this disease respectively, are cultured in four different nutrient solutions, each of which is consisted of fundamental solution plus(+MgO, +SiO_2), (+MgO, -SiO_2), (-M.O, +SiO_2), (-MgO, -SiO_2). Then the plants are sprayed with a definite amounts of a suspension of the spores of Pircalaria Oryzae Cav. (the causal fungus of Imochi disease of rice plant). SiO_2 deficient series are afflicted severely with this disease, especially in the case of (-SiO_2,-MgO) and though in SiO_2 series the plants are also suffering from the disease unless MgO be given. The cause of suffering from this disease will be explained as the result of the following physiological conditions : (1) When magnesium is deficient, plants become very juicy and late ripening. Thus plants are put into the condition of being afflicted with fungus. (2) Many silica cells are found in the leaves of the plants which are cultured in (+MgO, +SiO_2)series, but only a little in the case of (-MgO, +SiO_2), (+MgO, SiO_2), (-MgO, -SiO_2) series. (3) The magnesium deficient series show the high contents of total nitrogen and the high value of N/SiO_2 ratio. (4) The total concentration of cell saps is arranged as follows : (+MgO, +SiO_2)<(+MgO, -SiO_2)<(-MgO, +SiO_2)<(-MgO, -SiO_2) And the same tendency is found in the case of the concentration of soluble nitrogen and sugar.

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This is a report of genetic studies on the Japanese Acid Earth from Imai, Niigata Prefecture. The geological map and shematic profile ofthe location where the present sample was taken are shown in Fig. I-1 and I-2. In the Fig. I-2,P shows the rock which the author estimated to be liparitic tuff. In present case, the Japanese Acid Earth seems to be divided into two series according to the process of weathering, one is P-H_1-G_1 and the other P-H_2-G_2. The data of total analysis of the Acid Earth are given in Table I-1. Each content of H_2O from G_1 to H_2 is greater than that of P, these values indicating that the weathering is in process towards hydration. The ratio of SiO_2 : Al_2O_3 in each horizon is shown in Table I-2,and the value of G_1 to H_2 is very smaller than that of P, and moreover, the valueof G_1 and G_2 is smaller than that of H_1 and H_2. The value of P reaches 17.15 but when author culculated the average of chemical consistuents of the 16 liparitic rocks which are cited in Rosenbush's "Elementeder Gesteinslehre", this value was found to be 9.31. Judging from this number and the results of microscopic examination, the parent rock is concluded as glassy liparite or liparitic tuff. Therefore, it seems that the rock P rich in silica, is changing into H_1 and H_2 through the process of desilicification. At the same time, H_1 and H_2 gradually turn into G_1 and G_2 as the result of weathering, and the formergroup is richer in silica. The 10% HCl soluble component after Gedroiz is shown in Tabbe I-3. From these data, it is found that SiO_2 and Al_2O_3 in G_1 to H_2 are much easily soluble but alkali earth and alkali are not so easily soluble, but especially not is MgO. The Japanese Acid Earth is known by its acid reaction. So the author furthermore inveseigated of ths earth, the value of Exchange Acidity, Hydrolytcc Acidity and PH. P and H_2 are not so acidic but G_1 and G_2 indicate very high acidity. These values agree with the content of exchangeable hydrogen of every horizen. But base exchang capacity of H_2 is very high and followed by G_2,but that of H_1 and G_1 is fairly low. These value correspond to the amount of 10% HCl soluble SiO_2. Then, the author investigated the clay minerals which constitute the Japanese Acid Earth. For this purpase, he studied the dehydration curves and the differential heating curves of each horizon of the Acid Earth. From the form of dehydration curves (Fig. II-1), he was able to point out that the clay mineral of G_1,G_2,H_1 and H_2 belongs to a kaolinite group, but the form of P does not show such characteristic a type. The differential heating curves of G_1 and H_1 are shown to be the halloysite type, but those of G_2 and H_2 are not clealy defined (Fig. II-2). Then, in order to know the crystalline forms of these constituent clay minerals of investigated earth, he used for this purpose, electron ultramicroscopic photograph and X-ray diffraction diagram. The former is given in Fig. II-3. Needles crystalline halloysite is shown in G_1 sample only, but none in other samples. The diagram of X-ray pattern of earth is given in Table II-2. This result accounts for that the constituent clay mineral of investigated earth belongs to halloysite type. From these investigtions, the author has concluded that the clay mineral of Japanese Acid Earth consists of hydrated halloysite (Endellite).

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Generally, at the district of volcanogeneuos soils in Hokkaido snow accumlate a little and soil freeze about 30-100 cm. depth, author investigated process of freezing and thawing action of soil, their remedial measures for agriculture. In this report author described the process of freezing and thawing action of volcanogeneuos soil. (1) Form of freezing of volcanogeneous soils are differ markedly according to soil texture. (2) On observation of frozen profile of volcanic ash soils, ice pillar horizon existed numerous time repeatedly in the soil stratum and so called frozen soil horizon and ice pillar horizon alternaly to each other. (See Fig. 1) (3) On the observation of frozen profile of volcanic pumic soils, spaces between pumices are fulfilled by ice particles and pumices are also frozen. Interior of pumices are extremely dry state and moisture increase gradually towards outside and only the minute thin portion of surface of pumice are frozen. The drying states of interior of pumices become more and more less remarkable toward deep, at the same time ice particle also decrease, and unfrozen pumices internal moisture is uniform.(See Fig.2) (4) Volcanic sandy soils situate between volcanic ash soils and volcanic pumice soil, then its freezing form also possess both characteristics of them, but not so remarkably. (See Fig. 3) (5) On occation of thawing in valcanic ash soils, water which come from thawing of snow or from melting ice pillars in frozen soils are not permitted to penetrate to down on account of freezing state of lower stratum, moreover water of ice pillar horizons and frozen soil horizon have been brought through lifting of soil water content in the soil near are more abundant as if it is a paddy field. (6) In volcanic pumice soils, ice particles which have been fulfilled in the spaces between pumices are not result of lifted up from the below, water from melting ice particles are given buck again to pumices in neighbouring by their own absorption, even if all soils of sub-horizons do not melt, so amount of stagnated water on the ground surface are little. (7) On volcanic sandy soils, the freezing show such as forms that both of volcanic ash and volcanic pumice, therefore on occation of thawing the amount of stagnated water on the ground surface are few in comparision with volcanic ash soil, but excessive water are lifted up from the below, therefore drying soils after thawing of snow are delaid far much in spite of sand than ordinary soils.

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This investigation was performed after the methods of R.K.SCHOFIELD with slight revisions. The soil samples were placed in a series of buffer solutions containing calcium from pH2.9 to pH9.16,then titrated or measured conductometrically. The amouut of calcium taken from or given to a buffer solution of a know pH was determined by calculating from the difference of titre or the chage of conductivity between the original and reacted solution. In this investigation a comparison was made between the methods of titration and electric conductivity. It was found that by the method of titration, the calculated amount of calcium given out from the soil on the acid side was much more than that calculated from the method of electric conductivity. And on the alkaline side too, the calculated amount of calcium taken up by the soil from the titration method was more than that from the electric conductivity method. These discrepancies are considered as being caused by soluble aluminum on acid side and soluble humus on alkaline side, both of which have a great influence on the titration method but do not act as conductors in the reacted solutions.Therefore the method of electric conductivity is considered comparatively excellent. The relations between several soils and their buffer capacities were studied. The allitic soil of Nishiyukuta has a different buffer curve from the siallitic soils of Ozenji and Yamayi while the latter two are alike. The buffer curves of top soils and subsoils are also distinctly different.

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The nature of soil humus was studied by titration method after SIMON's idea. After the results the authors obtained the following conclusions. 1) B-type of humic acid (sol., in Mg-ion) predominated in podzolized brown forest soils, and A-type of humic acid (insol., in Mg-ion), on the contrary, in brown forest soils. 2) The soils of upland field in Japan, except podzolized brown forest soils, had always the tendency of the latter case. But the humus of these soils was observed to change its nature in somew hatbroad range depending upon the constituents in soils such as lime in A horizon, and sesquioxide as well as clay in B horizon. 3) The humus of soils of ground water soil type was inactive in general and had scarcely the nature of true humic acid. 4) In the valley-shaped areas caused by head erosion there existed always the dark-coloured soils of considerable depth. The humus of those soils was ascertained by the authors to be of similar nature to that of soils of upland fields (refer, to 2). The above similarity induced the authors to designate those soils as dark coloured colluvial soils.

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The rate of respiration of the root-nodules, deta-ched from roots, decreased with decreasing partial pressure of oxygen and increased somewhat in pure oxygen than in the air. But the rate of respiration of the bacteria centrifuged from nodules was not affected by decreasing percentage of oxygen. The concentration of KCN at the half inhibition of respiration was about 3×10^<-4> mol for centrifuged bacteria from soybean and vetch-nodules, and 5×10^<-5> mol for pea-bacteria from laboratory culture. For soybean nodules, 10^<-2> mol was needed for half inhibition, due to the probable inhibition of KCN penetration into the interior of the nodules. CO inhibitted the respiration of artificially cultured root-nodule bacteria about half or more in the atmosphere of 95% CO and 5% O_2,whereas the centrifuged bacteria from nodules was innert to CO even in that concentration.

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In this paper it deals with the morphological, mechanical, and chemical characteristics of the Yellow Soil of Mikatagahara, Pacific Coast of Central Japan (See Table 1 and 2). 1. The soil owes its morphological properties largely to a slightly moist condition, which may be brought about either by flat relief or by moist climate. The Soil is fine in texture, ranging from clay loam to loamy clay. The A horizon is impregnated with humus, while the B horizon is bright yellow in colour, and many thin and rusty brown seams consististiug of ferruginous compounds occur in the B_2 horizon. The A_2 horizon does not show any evidence of bleaching. 2. According to heavily leaching, the soil is very strongly acid in readtion and the degree of base-unsaturation reaches to about 90 percent throught the profile. The colloidal cray fraction of the various horizons are ferallitic in composition. The soil is more allitic and unsaturated than the yellow soils of South China and Formosa. 3. Exchange reaction (pH in water minus pH in 0.01 n Na_2SO_4) of the various horizons show neutrality or alkalinity. From this and other properties it may be considered that the soil is subjected to the anionic solvation and eluviation and, consequently, is not a product of podzolization.

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We have determined manganese in paddy soils from Aikawa, where field experiment improving the degraded paddy soil has been carried and the effect of the dressed manganous sulphate on rice plant was very much. Then the not degraded paddy soils have been analysed and compared with Aikawa soil. On account of these data we think that the "active" manganese after BREWER & CARR is not adequate in token of manganese-deficiency as so paddy soils. Much more adequate may be the reducible manganese, which is determined by treating with neutral N-ammonium acetate and hydroquinone, but another reducing agent may be selected instead of the latter.

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For the utilization of source of potash fertililizers, the dust of blast-furnace, that is byproduct of iron-works, were investigated on its potash contents, its properties for fertilizers, potash extraction methods, and other constituents that is injurious to plant growth. About70% of total potash of the dust is water soluble, and so water extraction of potash is easy, but practically difficult because of very fine powder, which float on or suspend in water. Dust contains potash 14〜1.7%, in several samples, besides ZnO 14〜2% andPbO about 1% that is assumed harmful to plant growth. Among the extraction methods of potash it is effective to calcine 400℃, 1hr. For rice and barley in pot cultures, dust gave nearly equal amounts of yields to KCl when suppling the same weight of potassium, but for barley dust was. inferior to KCl, but superior when liming. Among N-fertilizers together dust, calcium cyanide are most effective, but ammonium sulfat are not suitable. Fertilizing value of the dust are not determined K_2O%, but amounts of injurious elements, especially Zn, Pb. For examples, it is consider that Honkeiko iron-works' (B), that contains ZnO, Pb, gave injurious effect owing to only Zn, but Yawata's, that contains 14.48%ZnO, 6.77% Pb, combined effects of Zn, Pb.

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For the purpose to investigate specific charactor of soil which easily appeares the potash deficient symptoms to the rice plant, soil samples were collected from the several locality in Kyushu province. And investigated the relationship between dificulity or ease to appear the potash deficient symptoms and the Total K_2O, N/2 acetic acid soluble K_2O, potash fixation and the Ratio of ammonia absorptive power and potashium absortive power. The results summarized are follows : (1) We could not recognized the relationship between the deficulty or ease to appear the potash deficient symptoms on the rice plant and Total K_2O. (2) We have recognized the relationship between the dificulty or ease to appear the potash deficient symptoms on the rice plant and N/2 acetic acid soluble K_2O. But this relation are not higher so much. (3) We could not recognized the relationship between the deficulty or ease to appear potash deficient symptoms and the power of potash fixation. (4) The equivalent ratio of N and K_2O absorptive coeficient vary with the soil. And the soil which easily appear the potash deficient symptoms have the specific charactor, namely potassium absorptive coeficient higher than the nitrogen absorptive coeficient. (5) One milligram equivalent N and K_2O added to the 100gr air dry soil one by one or together. And applied the 0.1N or 0.01N solution of NaCl, CaCl_2,NH_4Cl or KCl and then analysed the K_2O and NH_4-N. The K_2O/N of soil which easily appear the potash deficient symptoms lower than other soil K_2O/N (6) The equivalent ratio and K_2O absorptive coeficient of 36 paddy soil in Kyushu have indicated the value of 1.0〜4.4 and 2.2 as average. The Granite soil and Tertiary soil have higher value than other soils.

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