Tabacco seedlings were cultured by the method (cited in part 1), which applied nitrogen in four degrees (0,10,40,130,p.p.m.) and phosphorus in three degrees (0,10,20,p.p.m.). 1) Yield of the seedling was maximum at 40 p.p.m. of N and 10 p.p.m. of P in the solution. 2) N-content of the seedling increased with increasing concentration of N in the solution, and this tendency was same in the relation between P-content and concentration of P. 3) Absorption of N was different between two plots, 40 p.p.m. and 130 p.p.m. This difference was considered to be caused by the difference in applied concentration of P. N was of non-protein. 4) Applied with same cocentration of N, P was always absorbed more in the plot of 20 p.p.m. than that of 10 p.p.m. P was of non-protein. 5) Soluble carbohydrate decreased with increased N application. It was always more in the plot of 10 p.p.m. P than in that of 20 p.p.m. P, in the case of being applied with N in same concentration.

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Comparison was made between fused phosphate and superphosphate in the manurial value for barley, cultivated on the field of manganese-deficient area, Kamiide-village, at the foot of Mt. Fuji. Results were as follows. 1) Fused phosphate increased pH of the soil, and decreased the amount of available manganese. Barley was damaged by the deficiency of manganese. 2) By dressing manganese fertilizer, the yield of barley was recovered, especially in the case of being overlimed.

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Of manganese in sand soils at Yumigahama Peninsula, Tottori prefecture, some studies were made. The results were summarized as follows : (1) Studied soil cotained much calcium, but little clay and humus, its pH value being nearly 7.0. (2) 0.2 N-HCl solble manganese in the soil was as much as divalent manganese which was active. (3) In the above soil comparatively much iron was contained but little manganese, particularly little divalent manganese which was active, exchangeable and soluble in water. (4) Authors were of the opinion that the tetravalent manganese which was determined as an active manganese was of an unabsorbable. (5) In studied soil there exsited in great quantity not only tetravalent manganese which was active but also the manganese either insoluble or difficult to be dissolved. (6) Exchangeable manganese in applied sandy soil was increased by the addition of the flowers of sulphur as well as such a reducing material as dextrin, and was decreased by the addition of calcium carbonate. By these additions the change in pH values was expected. (7) With regard to the relations between the deficiency in manganese and that in iron, experiments were conducted in water culture with "Hadaka" barley and the following results were obtained. Soluble Fe/Mn ratio in the tissue of a living body in healthy growth was within the limit of the value from 2.6 to 3.5. In case of the value being higher or lower than the limit, chlorotic phenomena took place.

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As usually known, clay suspension becomes less turbid with the elapse of time for settling. The change of this turbidity was traced by the transmittance of monochromatic light (610 mμ of length), expecting the change might reveal somewhat the nature of clay particle. Clay suspension, of proper concentration, was introduced into the glass cell (1 cm × 1 cm × 3.8 cm) equipped to electric photometer and a downward movement of suspension, through the slit 5 mm in height, was traced by reading the transmittance every 30 min. for 3 hours. At the beginning the suspension was so suitably kept that its upper margin reached the upper surface of the slit, and it was allowed to begin to settle. Consequently, a clear supernatant liquid could occupy the slit the more widely in height the more the time for settling passed. Of seven soils from genetic horizons of both Brown forest soil and Reddish brown soil (acid mineral soil), the transmittance of above means was determined, results of which were shown in Plate 1 and 2 (refer to Table 1). From Plate 1 and 2,it is obvious that the curves of soils from B_1 of Kokubunji (T51) and also from B_2 of Mizunami (M 3) were particularly of wave-like feature. The causes of wave-like feature may be explained in several ways. But, one of the causes may be the following fact : in the above horizons, soil particles are of comparatively heterogeneous nature and are inclined to settle somewhat in various manners. Of the causes, more experiments will be made.

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Relationships between phosphorus nutrition and extracellular phosphatase activities of crop roots were studied with rice plant, wheat, and barley. The results may be summarised as follows : 1. Glycerophosphatase in crop roots, deficient in phosphorus, tends to have higher activity than that in the roots of normal constituents. This higher activity is also observed in the root, when they were ground or killed with chloroform vapor. (Table 1 and Fig. 1) 2. Other phosphatases - nuclease, monophenylphosphatase, diphenylphosphatase and pyrophosphatase - in crop roots. deficient in phosphorus, have also the same higher activity as glycerophosphatase. Both phytase and metaphosphatase are scarecely detectable, irrespectively to phosphorus nutrition. (Table 2) 3. Activity of glycerophosphatase in roots of rice plant increases apparently in proportion to the decrease of inorganic phosphorus concentration in plant tissues. (Fig. 2.) 4. Of both plants, rice plant and barley, phosphorus in nucleic acid is utilized more efficiently by the roots, deficient in phosphorus, than those of normal constituents. (Fig. 3) This higher ability of utilizing organic phosphorus of the roots is considered probably to due to their strong power of mineralizing organic phosphorus and absorbing inorganic phosphorus. At the above utilization, it is ascertained that organic phosphorus is mostly mineralized by extracellular enzyme of the roots, and so developed inorganic phosphorus is absorbed by them. (Fig. 3.)

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1. We investigated on the sedimentation volume of some diluvium soils, known as Allitic soils, 2. For electronmicroscopy the soil colloids from the above soils were selected. 3. From the results of these investigations we inferenced the dispersion system of soil colloid as follow : colloidal part of top soils was in "Sol" state, while that of sub soils was in "Jelly" state. And in a part of sub soil we could recognise the homogenous (non structural) mass, which was considered as a "Gel" type material produced in an early stage of chemical weathering.

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We studied on the bond between the inorganic colloid (Kaolin, Japanese acid clay etc.) and orgatnic soil colloid (Humus) by the method of colloid itration and electrophoresis. 1) Humus acted as a protective colloid for the clay minerals. 2) Humus had the greater equivalent per gram in the lower concentration, between 0.0225% to 0.0045%.

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In this part the suitability of asparagine, ammonium salt, nitrate, and nitrite for the growth of rhizobia was examined. Yeast water (0.5% Vol.)-mannitol-mineral salt solution was used as a basal medium, because most of the rhizobial strains were unable to grow in a simple synthetic medium, although strains from Robinia, Lotus, Sophora, Amorpha, Caragana, Astragalus, Sesbania, Dalea, Indigofera, Styphnolobium, and some strains of soybean-and cowea-group were able to grow in it. The root nodule bacteria are divided into the following groups on the basis of the kind of utilizable nitrogen compounds. 1. Asparagine, ammonium salt, nitrate, and nitrite are all effective. ……strains from pea group, clover group, bean group, alfalfa group, soybean group, cowpea group, Sesbania, Mimosa, Leucoena, Dalea, Styphnolobium, Sophora. 2. Asparagine, ammonium salt, and nitrate are effective. Nitrite is ineffective. (Not all strains in this group are unable to attack nitrite.) …………strains from alfalfa group, lupine group, soybean group, cowpea group, Indigofera. 3. Asparagine and ammonium salt are effective. Nitrate and nitrite are ineffective. ……strains from cowpea group, Indigofera, Astragalus, Lotus, Caragana, Amorpha, Robinia. 4. Ammonium salt, nitrate, and nitrite are effective. Asparagine is ineffective. …… strains from bean group, Sesbania, Vicia (nipponica). 5. Ammonium salt and nitrate are effective. Asparagine and nitrite are ineffective. ……strain from soybean group. 6. Asparagine is effective. Ammonium salt, nitrate, and nitrite are ineffective. ……strains from cowpea group. Not few strains from lupine-, soybean-, cowpea-group, and Sesbania seem to bring about the loss of nitrogen in nitrate or nitrite medium.

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Al-P system The present paper dealts with the interaction between H_3PO_4 and AlCl_3 solutions varying their concentration and proportion at different pH values. The experimental conditions and procedures except using AlCl_3 as an Al source are quite similar to those of Fe-P system in previous paper. Results obtained this time were as follows : (1) Fixation curve of P in Al-P system was substantially in agreement with that of Fe-P system in its shape. However, fixation of P took place at higher pH range, from about 3 to 10,compared to range of the Fe-P system. (2) Optimum pH range of P-fixation was affected by P/Al ratio of the system; and the lower the ratio, viz., the higher percentage of Al was, the higher the pH of range was. (Fig. 1). (3) Complete fixation of P was observed only in the series where P/Al ratio was less than unity. Therefore, when P/Al ratio of the system was above unity, viz., when added P in the system was present equivalently or excessively to Al, P was not so much fixed as 100 per cent; concequently some portion of P remained in a soluble form. For instance, the percentages of fixed P in each series, P/Al ratio of which being 2,1 and below 0.5,were 50,80 and 100,respectively (Tab.1). (4) The pH range of complete fixation (retention) of Al coincided with that of the maximum fixation of P, but it was shifted to higher pH values with decrease of P/Al ratio of the system (Tab. 2 and Fig. 2). Comparison of Fe-P system with Al-P system. (1) Being added in the both systems P was fixed by Fe or Al at all pH zones except alkaline and strong acidic reactions; and its maximum fixation took place at several pH value according to conditions namely, the pH value varied with P/Al or P/Fe ratio of the system; the lower the ratio was the more the pH was shifted to higher value. (2) In the both systems the percentage of the P-fixation decreased with increase of P/Fe or P/Al ratio of the system, and no difference was between the both systems in their decreasing manners. (3) Fixation of total P was completed only in the series, when P/Al or P/Fe ratio was less than one equivalent (Tab. 3). (4) However, the pH zone which caused the maximum fixation of P was of higher value in the Al-P system than in the Fe-P system (Tab. 3). (5) SWENSON has recently noted that Fe- or Al-compounds of P formed in the pH range of 2 to 7 should be basic Fe- or Al-phosphate formulating Fe(H_2O)_3(OH)_2・H_2PO_4 or Al(H_2O)_2・H_2PO_4. From this point of view, the conclusions were obtained with precipitated products in the following way. (Tab. 4). Only in the series, P/Fe or P/Al ratio of which being 2,all the preciptates were produced in such a form as the above mentioned. With further lowering of the ratio below unity, basic Fe- or Al-phosphate decreased in the precipitates and hydroxides of iron and aluminum increased. Though all of retained P in the series whose P/Fe or P/Al ratio was 2 was in the form of basic Fe- or Al-phoshate, the proportion of the phosphate present in the precipitates was only one half of added P; while remaining half portion was in a soluble state for depletion of Fe or Al. On the other hand, when the above described ratio was below unity, all of added P was fixed as basic Fe- or Al-phosphate. (6) The retention curve of Fe was nearly identical with that of Al, aside from the following two points pointed out as a discrepancy : a) The solubility of Fe which was raised once at a weak alkaline reaction started to be again suppressed with further advance of pH value, and finally all of Fe flocculated. Contrarily, in the Al-P system, such a phenomenon has not been found as to Al, because of the fact that Al enters into solution depending upon the formation of aluminate at an alkaline reaction. In short, the point of this temporal solubility reduction of Fe at a weak alkaline reaction in the Fe-P system was correspondent to a point of inter section of the solubility curve of

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Nemuro and Kushiro districts in the eastern part of Hokkaido have unfavorable climate for agriculture. Moreover, they are covered with volcanic ash soils erupted recently from Mt. Mashu. So, Nemuro and Kushiro are representative districts of low productivity in Hokkaido. These districts were appointed repeatedly as sites for proposed reclamation work. But, unfortunately, no good results have been obtained. About 20,000 ha of flat land are left unclaimed. So, authors intended to make clear the characteristics of soil which covers these districts and find out the fundamental idea for the maintenance of the fertility of the soil. These districts are covered with more than ten layers of volcanic ashes erupted from Mt. Mashu. Authors selected four layers from surface which has direct effect on the crops cultivated there, and called them : Mashu-a, M-b, M-c, and M-d from the top layer downward. The soils, derived from layers M-a and M-b, are very young suffering weakly from weathering; and almost all their exchange capacities are due to the humus, not to inorganic colloid. However, the soils, derived from M-c and M-d, have some amounts of inorganic colloid which has exchange capacity. But all in these cases, the soils contain free aluminium of considerable amount. So, in the case of M-a and M-b, we must prevent the soils from the exhaustion of humus; and in the case of M-c and M-d, from the unfavorable influence of free aluminium.

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The inhibition of nutrient uptake by rice plant was studied by increasing concentrations of butyric acid or respiration inhibtors such as H_2S, NaCN and NaN_3. Rice plants were grown by customary water culture technique and treated for 28 hours in the green-house with various concentration of these inhibitors in the basic nutrient solution as shown in Table 1. The nutrients uptake was calculated from the concentration difference of the respective elements. The results are shown in Fig. 1 : (1)〜(10). In general, the relationship between the nutrient uptake and the concentration of inhibtors can be represented by y_i = a_i + b_ie^<-cjxj> where y_i represents nutrient uptake, x_j the concentration of inhibitors, i and j being variables according to the kind of elements and inhibitors respectively. a_i respresents y_i at x_j →∞ and was designated as Ultimate-absorption, the approximate values of which are shown in Table 2. Further, the Inhibition Coeffieients of nutrient uptake were calculated by ((y_<i(xj→0)>-y_<i(xj→∞)>))/(y_<i(xj→0)>)×100 as shown in Table 3. The Ultimate Absorption a_i seems to be almost independent of the kind of inhibitors but primarily dependent on the kind of elements. The Inhibition Coefficients decreased according to K_2O・P_2O_5>SiO_2・SO_3・Br>MnO・NH_4-N・H_2O>MgO・CaO. The outstanding depression of P_2O_5 uptake was doubtless as repeatedly revealed in Fig. 2. The result was discussed on the basis of the essential mechanism of aerobic respiration, K_2O and P_2O_5 probably linking more directly in the metabolic cycle and MgO and CaO standing more indirectly or far apart from the cycle. Practically, this will give important suggestion to the improvement of the nutritional status of the crop plants in such cases as the metabolic activity of their roots are inhibited by toxic substances (for example H_2S and butyric acid to rice plant), cold climate, draught or bad drainage.

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Both soy beans for summer and autumn were planted on the soil, deficient in magnesium. Of each plot applied with Mg-sulfate in increasing amount (see Table 1), leaves and stemes were sampled every two weeks. With these samples, magnesium was determined separately in three forms, water suluble, 95% alcohol soluble, and 0.5% HCl soluble. (see Table 1,2,3 and 4; Fig 1〜6) Refered to three periods of growing, flowering and podding, magnesium was seemed to be essential to produce pod. In general, Mg, sol. in H_2O, was most easily moved, while Mg, sol. in HCl, not so easily to be brought to be moved. When Mg, sol. in H_2O, decreased less than about 0.1% Mg, sol. in HCl, also began to decrease; The former magnesium contained 0.0〜0.5%, the latter became naught. Mg, sol in alc, decreased with the above decreases. Mg deficient symptom emerged, when Mg became 0.05〜0.1% in total. It was concluded that magnesium deficiency might occur when its amount sol. in H_2O, was reduced lees than 0.04%.

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