1. Clayey soil at Higashikawasoe in Saga prefecture, sandy soil at Fukuma in Fukuoka prefecture and zeolite at Yokote in Akita prefecture are found having the property of fixing large quantities of ammonium when they are dried after an ammonium choride solution is added to them. The Higashikawasoe soil is the one which is derived from marine alluvial deposits, and the Fukuma soil is the one which is originated in the granite. The ammonium fixing-power of all soils studied with exception of above-mentioned samples is observed to be very weak or none. 2. Ammonium fixing-power of soil increases with depth in the most cases. 3. Correlation coefficient between the amounts of ammonium fixed and that absorbed is calculated to be 0.69,0.05 in fifty samples studied, but it seems that the fixation of ammonium is not a phenmenon which attends always to an absorption of that ions. 4. Very small amounts of ammonium volatilize at the drying process on the water bath. 5. Higashikawasoe soil, Fukuma soil or zeolite fixes an appreciable amounts of ammonium ions under moist conditions. 6. Drying a soil after an ammonium chloride solution is added to the soil results in greater fixation than when it is kept under moist conditions.

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Comparison of NO_3-N and NH_4-N as the nitrogen sources to tomato plant was investigated by the constant renewal water culture method. In general, NO_3-N was better nitrogen source to tomato than NH_4-N, but its degree varied with conditions such as pH and other ion-concentrations of culture solution. When NO_3-N was used, optimum pH was and tomato was relatively insensible to k-mangel, but NH_4-N was used, optimum pH was near 8.0 and very sensible to k-mangel.

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Investigations on the nitrogen metabolism was regarded as of great importance among the matter concerning plant nutrition. Especially in Japan, rice plants are raised at paddy field under waterlodged condition, thereby rice-plants preferentially absorb ammonia-nitrogen than nitrate form. We have attempted to explain the mechanism of nitrogen metabolism through qualitative and quantitative investigations of assimilation process on absorbed ammounia-nitrogen by roots. Riceplants (Norin No.18) were cultivated in Wagner pots. For nitrogenous fertilizer, sulphate of ammonia was given as basie application and top dressing at different stage, and then the growth and yield of rice crops were carefully examined. Among all plots, the best result was obtained at one of basic application and in addition top dressing at primordial stage, namely about three weeks before heading. Starch, reducing and non-reducing sugars were estimated about whole samples taken once a week. From the standpoint of carbohydrate accumulation, shortly after transplanting stored carbohydrates were exhaused. Then the content of carbohydrate generally arises, but at the younger stage nitrogen assimilation predominates than carbon assimilation. After primordial stage the photosynthesis exceeds the nitrogen assimilation. Dressing of nitrogen rapidly reduces the content of carbohydrate in the rice plant, and after some interval again rearises to the degree far higher than before. Especially dressing of primordial stage has strongest effect of promotion of carbohydrate content. This causes an effective increasing yield of crop.

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Fractional determination of nitrogenous substance in aforementioned sample, was made in order to explain the process of nitrogen assimilation. Total nitrogen contents rises to maximum, immediately after transplanting and decreases gradually with the growth of rice plant. Protein-nitrogen also shows a same tendency. Increase and decrease curves in the contents of soluble nonprotein-nitrogen is a bimodal curve, which has two maximum namely before primordium and after heading. Amide-nitrogen has a same tendency. Ammonia-nitrogen increases previously to the soluble state and hendecreases. Nitrate-nitrogen was found tracely. Two maximum content of nonprotein-nitrogen are translocation form of protein, namely enrichment before primordium and movent to the ear after heading. Top dressing of nitrogen, makes temporaly rise of protein-nitrogen but at the harvest as a result of increase of dry-matter, total nitrogen content of crop drops. Rate of combination of nitrogen dressed at the primordial stage, to the product of photosynthesis is most rapid than before and after primordium.

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The rice plant was cultured in nutrient solutions which have various degrees of the potassium concentration (from 0 to 200 p.p.m. K_2O). (1) The maxium yield of the rice plant is obtained at the concentration of 20 p.p.m. K_2O in the culture solution. And above 20 p.p.m. K_2O, the yield remains constant independent of the concentration of potassium in the culture solution. (2) The potassium content of the rice plant increeses in logarithmic curve according to the increeses of potassium concentration in the culture solution. (3) There exists the marked interrelationship between the yield and the potassium concent of the rice plant. Judging from this interrelationship, four stages are distinguished in the condition of the rice plant, Namely, 1st step : in the case of low concentration (0〜5p.p.m. K_2O), both the yield and the potassium content of the rice plant increese with the increesing potassium concentration in the culture solution. This step may be called "the deficiencystage" 2nd step : in the case of optimum concentration (5〜20p.p.m. K_2O), the yield of the rice plant increases with the increase of potassium concentration in the culture solution, but the potassium content of the rice plant remains comparatively constant. This step may be called "the normal stage" 3rd step : in the case of high concentration (above 20p.p.m. K_2O), the potassium content of the rice plant increases markedly with the increase of potassium concentration in the culture solution, but the yield of the rice remains constant. This step may be the so-called "luxury consumption stage" 4th step : within the range of present investigation(0〜200p.p.m. K_2O), we can not observe "the excess stage" as cited in the case of nitrogen and phosphorus. But, we think, there may exist the excess stge in the case of higher concentration of potassium in the culture solution. (4) The absolute amount of potassium absorbed by the rice plant increases with the increasing potassium concentration in the culture solution. And the maximum distribution of potassium in the ear is found at tke concentration of 5 p.p.m. K_2O in the culture solution.

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In the first report, authers studied on the nature of five soils(Wakkanai, Hamatonbetsu, Kami-Otoineppu, Soeushinai and Enbetsu) in the northern part of Hokkaido and concluded that Hamatonbetsu soil is iron podzol developed on sand dune and the others are gray brown podzolic soil. In this report, we studied on the nature of six soils collected from the adjacent southern area (Rumoe, Wassamu, Omu, Shirataki, Toma and Monbetsu). The distribution of particle size, the amounts and properties of soil humus and the amount of colloidal matters extracted by Tamm's acid-oxalate are determined. Moreover, the inorganic components, acidities and base-exchange capacities are estimated. Judging from the results obtained we concluded that Rumoe and Wassam soil are gray brown forest soil, Omu and Shirataki soil are leached brown forest soil and Toma and Monbetsu soil are brown forest soil respectively.

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1. More amount of humus was found to be accumulated in plot dressed with phosphate than in plot undressed with that component. 2. Humus more liable to decompose was found to be accumulated in phosphate-dressed plot than in undrssed plot with phosphate. In other words, there must be some differences in the form of humus or nitrogenic substance in both plots. 3. Therefore the dressing with phosphate increases soil fertility owing to above-mentioned two points : in this paper the second point was considered to the increase of fertility and discussed its contributing mechanism.

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A series of chemical analyses conducted by me obtained the following results : - 1. There exists a certain amount of Manganese in vaious part of the plant and it is remarkably rich in the pollen. 2. The kind and relative amount of nourishments held in the soil are respensible for the differences in the amount of Manganese detectable in the peeds, stems and leaves. 3. The fertile soil excels the futile one in holding at least more quantity of Manganese dissolved in KCl solution and also dissolved in HCl solution.

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

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1) The molybden content in the soil at Uedadistrict was as follows. The minimum content : 0.02 P.P.M. the maximum content : 0.43 P.P.M. the mean content : 0.29 P.P.M. 2) The molybden content in green leaves was variable with the kind of plants. Generally, the content in the vegetable was large and in permanent plant was small.

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We conducted seried pot experiments with barley using 2 typical volcanic soils to make clear fertilizer effects of the fused magnesium phosphat. Generally speaking, the fertilizer value of phosphorus in the fused magnesium phosphate was as high as that in the superphosphate. But, -10 mesh samples or quenched product not ground but sieved, which showed that highest effect for paddy rice, was less effective than finer one. It seems better to ground the phosphate to a finess of -70 mesh. For barleys on Ogurobara Strongly acidic soil of which magnesium deficiency was found, the fused phosphate gave by far more beneficial effect than the superphosphate did! The alkaline nature and magnisium content of the former were as effective as these of slaked lime and magnesium sulphate for increasing crops and their magnesium content as well as for liming the soil acidity. Silica in the fused phosphate was also effective as that in water-soluble sodium silicate was, for increasing the silica content of the barley on Ogurobara soil.

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1. The effect of the potassium on the yield and panicle formation of rice plant was examined by water culture methods. Fig. 1. shows the design of experiment. 2. The effect of potassium absorbed during 35 to 45 days before heading is maximum on the increase of grain yield. 3. Greater part of the increment of grain yield in this period is due to mainly the increase of number of grad and number of heads, and another part due to the increase of fruit bearing percentage and weightd of 1000 grains. 4. While, the potassium absorbed after this period principally increased the fruits bearing percentage and weight of 1000 grains. 5. In the head of low potassium dontent (plot I and II) the sterile grains appear not only in the group of inferior spikelets but it of superior spikelets.

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We have determined manganese in the degraded paddy soils from Yoshida and I-dori. Thus we could ascertain our previous conjecture, that is, much more adequate ia token of manganese-deficiency as for air-dried paddy soils may be the reducible manganese, determined by treating with neutral N-ammonium acetate and hydroquinone.

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From the absorption of Ca and NH_4 ion by the soils in Ehime-ken, the following facts were obsorved. (1) The, amount of Ca absorbed by the noncolloidal fractions of the soils was, in every case, found to be almost equivalent to the amount of NH_4 absorbed. (2) On the contrary, the amount of Ca absorbed by the colloidal fraction was markedly greater than the amount of NH_4 absorbed, indicating that the colloidal fraction contains two different sorts, of H ion, one exchangeable and the other nonchangeable by NH_4 ion. (3) As is well-known "total exchange capacity" is often variable with the mothers used. This may be able to be partly explained from the facts above observed.

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There are many rapid methods of determing the constituents in the soils ; among them SPURWAY's as well as MORGAN's are popular. Modifying the SPURWAY's method the authers fixed he method of determining the approximate amount of exchangeable calcium in eight degrees shown in Table 3.

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