In this report, the relation between occurrence of`Goma-sho'and rate of nitrogen basal fertilizer was investigated in Chinese cabbage. The rate of nitrogen fertilizer tested was 10, 20, 30 kg per 10a. The occurrence of`Goma-sho'was generally promoted by increasing of basal nitrogen fertilizer. The striking occurrence was found in all plants cultivated with 30kg of nitrogen fertilizer and often in big plants cultivated with 10 and 20 kg of nitrogen fertilizer. These`Goma-sho'plants had a relatively high amount of nitrate and alpha amino nitrogen and low amount of sugar. It should be noted here that the symptom of `Goma-sho'was pronounced when the contents of these nitrogen compounds were higher in leaf blades than in midribs. from these results, it was concluded that for prevention of`Goma-sho'the optimal rate of basal nitrogen fertilizer was less than 20 kg per 10a and the physiological cause of this symptom was due to imbalance of nitrate, alpha amino nitrogen, and sugar contents.

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About 50 cultivated soils collected at Kameoka basin, Kyoto, were used for the determination of total, water-soluble, and hot-water soluble selenium in the soils. Soluble Se was extracted with water (soil: water=1:10) at room temperature for 24h or in a boiling water bath for 30 min. 1) The average Se contents of plow and second layer soils were 0.288 (0.64-0.16, n=51) and 0.323 (0.56-0.11, n=21) ppm, respectively. Although the mean content of second layer was a little higher than that of plow layer, Se leaching from surface horizon to under layer did not appear. In addition, there was no relation between the Se content of the soils and that of mountain soils surrounding the Kameoka basin. 2) On particle-size fractionation, Se contents of each fraction (coarse sand, fine sand, silt, and clay) showed 0.0n ppm order. this indicated that most Se in soil was in an easily soluble state. 3) Water-soluble and hot-water soluble Se were 8.9 and 20.4 ppb, which amounts to 3.1% and 7.2% of total and these soluble Se were also significantly high. Moreover , the correlation between increased Se and amino acid in hot water as compared to water (hot water soluble-water soluble) was significant. From these results, it was considered that the proteinaceous fraction of soil humus was decomposed on heating, and Se dissolved as low molecular compounds, such as Se-amino acids.

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The structures of ear formation and carbon partitioning (chased by ^13C) in different tillers were compared in semidwarf high-yielding (cv. Suweon 258) and conventional japonica (cv. Musashikogane) varieties. The ear yielding by main culm and primary tillers of Suweon 258 was high as compared with those of Musashikogane. Larger amounts or proportions of the carbon stored in the culms plus leaf sheaths before heading were translocated to the ears in Suweon 258 than in Musashikogane. The amounts of carbon fixed by Suweon 258 afer heading were more than those by Musashikogane based on either leaf dry weight or leaf nitrogen content. The linear relationship between ear weight and amount of fixed carbon was observed among tillers of Suweon 258 after heading, whereas in Musashikogane the relation leveled off at high amounts of fixed carbon, suggesting that the sink size (ear weight) limits yields in Musashikogane.

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Melon plants (var. Earl's Seinu) were cultivated with rockwool culture in a greenhouse. The experiments were composed of 8 plots in which three factors were combined: 1) different forms of rockwool; 2) shading on the bed; 3) controlling of nitrate supply. The results are summarized as follows. 1. In the case of cultivation with granulated rockwool, no fruit cracking was observed. 2. The shade on the rockwool bed increased the weight and the size of fruits by lowering the bed-temperature in summer. 3. The occurrence of irregular net on fruits decreased when the nitrate supply was depressed in fruit maturing stage. 4. Nutrient formula prepared by the group at Shizuoka University was similar to the nutrient composition that melon plant absorbed. From these experiments, it is surmised that in order to produce good-quality fruit, it is better to use granulated rockwool bed with shade and to supply nutrients in low nitrate concentration in the fruit maturing stage.

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Factors leading to the variations in phosphorus absorption by crops were investigated in a Tsukuba volcanic ash soil. In the plots where no fertilizer phosphorus was applied, C_4-type crops (corn and sorghum) absorbed more phosphorus than C_3-type crops (soybean, upland rice, wheat, and buckwheat). Varietal differences in phosphorus absorption were observed in corn. The response of soybean to phosphorus application was high in terms of dry matter production and phosphorus absorption. Absorption of phosphorus was largely dependent on the phosphorus mineralization or release from soil, fertilizer, and green manure. Absorption of P from green manure (sorghum) by wheat was as effective as that of P from chemical fertilizer. The contribution of phosphorus released from soil biomass was estimated to be small fractions for the growth of wheat.

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The quantities of phosphorus in wheat plants grown in a Tsukuba volcanic ash soil were linearly related with the root dry mass. The absorption rates (absorbed P per g DW of roots) was higher in the soil that had been applied a large amount of P fertilizer than in the soil where no P fertilizer was applied. The amounts of phosphorus absorbed by 8 summer-grown plants and 11 winter-grown plants were highly correlated with their root dry mass. Rape roots had higher P absorbing activities in terms of absorbed P per root dry mass. The amounts of phosphorus absorbed by paddy rice plants in a pot experiment were also correlated with their root mass. The increase of soil temperature enhanced the P absorption rates of rice roots.

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Quantitative studies were made on minerals in 4 samples of a convertor slag containing 16-21% Fe. Most of Fe was present in the forms of Fe(II) and Fe(III) while metallic Fe was present in small amounts. Major iron-containing minerals were Fe_3O_4, α-Fe_2O_3, FeO, and 2CaO・Fe_2O_3. The solubility of Fe_3O_4 was 10-20% in 2% citric acid and 35-60% in 1/2 M HCl, while that of other iron-containing minerals was 15-40% in the citric acid 50-90% in the HCl. Other major minerals were β-2CaO・SiO_2, 3CaO・MgO・2SiO_2, and merilite; a solid solution of 2CaO・MgO・2SiO_2 and 2CaO・Al_2O_3・SiO_2. 2CaO・SiO_2 and 3CaO・MgO・2SiO_2 were highly soluble while 2CaO・Al_2O_3・SiO2 was less soluble. The samples contained small amounts of Mn and P_2O_5 but minerals containing those components were not detected. Mn and P_2O_5 may be contained mainly in a vitreous phase.

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In a previous paper, we examined the effects of various organic compounds on NO_3 metabolism and related biochmical reactions occurring in a 24-h period in the Konosu soil (Halaquept) amended with nitrate. Organic compounds were found to be classified into 4 or 5 groups on the basis of changes in the amount of CO_2- and N_2O-production with increasing amount】of the added organic compounds. In this paper, we examined the effects of these organic compounds on the NO_3 metabolisms in another soil, Tanashi soil (Andept). We observed that the effects of organic amendment on the NO_3 metabolisms were essentially the same as in the Halaquept: 1) Glucose, sucrose, etc., were converted quickly and completely into CO_2 and strengthened reduced state of the soil at any level of their addition. Denitrifiers were taken over by fermentative anaerobes when their addition became large. 2) Addition of fumarate enhanced denitrification at any level of their addition. 3) Glycerol, alanine, etc., were not good substrates for any biochemical reaction. 4) Methanol was not utilized by any biochmical reaction.

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To clarify how nutrient status in soybean shoot affects root nodulation, the relationships among root nodulation, nitrogen and phosphorus contents of shoot, and its growth were examined. 1) Nutrient status of soybean affecting root nodulation: In a humus-rich Andosol, soybean (Glycine max L. Merr, var. Nanbushirome) was grown under field conditions with a combination of fused phosphate, superphosphate, and ammonium sulfate application. At flowering and pod-elongation stages, numbers and weight of root nodule were measured. The relationships of the nodulation parameters to shoot growth, N% and P% of shoot were examined. Shoot dry weight and P% at any stage positively correlated with nodulation. Not leaf N% in earlier growing stages negatively correlated with nodulation. Multiple regression analysis further indicated that enhancement in shoot growth resulted in a higher root nodulation. N% in shoot at an earlier growing stage (4th trifolilate leaf-folding stage) was a critical factor in suppressing nodulation of soybean was examined in 84 field plots. Numbers and weight of nodule correlated with shoot dry weight. Nodule weight in the plots fertilized with more than 60kg N/ha was much less than that in the plots which received less nitrogen. Fluctuation in nodulation found in the Andosol could be explained on the basis of the multiple regression parameters obtained in the above experiment. The ratio of the increase in nodule numbers to the increase in shoot dry weight after flowering was much lower than that before flowering. However, the ratio of the increase in nodule weight to the increase in shoot dry weight after flowering did not significantly differ from that before flowering.

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