In warm regions of Japan, methods of nitrogen fertilizer application and the effect of organic matter application were studied for direct sowing culture of the high-yielding rice variety"Akenohoshi"on well-drained paddy field. Grain yield of Akenohoshi attained the maximum value by dressing 16 to 18 kg of nitrogen per 10a. As to the methods of nitrogen application, dressing at the beginning of irrigation, dressing at the neck-node differentiation stage, which resulted in the higher yield in spite of the lower percentage of ripened grains. The yield of Akenohoshi was approximately 700 kg per 10a and it was 15% higher than that of Nakateshinsenbon (a common local variety). In addition, the yield was obviously enhanced by the successive application of rice straw and rice straw compost, especially straw compost gave higher yield. The yield of Akenohoshi ranged from 740 to 833 kg per 10a for four years, from 1984 to 1987. The effect of organic matter for Nakateshinsenbon was not so remarkable as Akenohoshi, which suggests that it is to one of the characteristics of Akenohoshi than by Nakateshinsenbon irrespective of organic matter application. The difference of nitrogen absorption between Akenohoshi than by Nakateshinsenbon irrespective of organic matter application. The difference of nitrogen absorption between Akenohoshi and Nakateshinsenbon was much enlarged in the plot with rice straw compost. Production efficiency for brown rice by the unit of absorbed nitrogen was distinctly higher in Akenohoshi. Seven hundred to eight hundred kilograms of grain yields were obtained at the number of forty to fifty thousands of spikelets per m^2, respectively. Percentage of ripened grains was 80 in this case. It is the standard number of spikelets in obtaining the targeted yield of Akenohoshi. It was pointed out that the yield of Akenohoshi was always higher compared with that of a local variety, Nakateshinsenbon, under direct sowing culture in well-drained field. Moreover, the effect of organic matter application on Akenohoshi was prominent.

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Sewage sludge was collected from four wastewater treatment plants in Sapporo city; respective two plants treated the sewage with and without chemical precipitation by lime and ferric chloride. In the following, these sludges are designated as"limed sludge"and"no-limed sludge."Ashes were made from these sludge samples by 800℃ incineration. In addition to these materials, one compost derived from limed sludge was provided. Various chemical properties, especially the status of phosphorus and heavy metals, were analyzed to determine the effect of the incineration process. 1) pH was higher in limed sludges than n no-limed sludges, and lower in compost than in limed sludge. There was, however, no change in pH by the incineration treatment. 2) EC were higher in limed sludges than in no-limed sludge because of elution both of alkali and alkali-earth metals. By the incineration treatment, EC did not change in limed sludge, but were slightly increased in no-limed sludges. 3) Sewage sludges and compost contained 2.4 to 3.5% of total P_2O_5. By the incineration treatment, water-soluble P_2O_5 was decreased but acetic acid-soluble P_2O_5 and citric acid-soluble P_2O_5 were increased 1.2-4.8 and 1.1-1.8 times, respectively. 4) Some heavy metals which possess relative low-boiling point were evaporated by incineration treatment. Heavy metal which possess relative low-boiling point were ashes were, however, in the order of Fe>Al>Mn>Zn>Cu>Cr>Pb≒Ni>Co>Dd, in general. 5) The incineration treatment was very effective in insolubilization of heavy metals contained in sewage sludge, since it decreased significantly water-soluble, exchangeable and absorbed fractions, except Cr, and increased insoluble fraction.

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A greenhouse experiment was conducted to compare (1) application effect on the growth of oats between two kinds of conditioning for sewage sludge with different dewatering methods and those ashes and (2) uptake of heavy metals by oats. 1) Application effect of nitrogen contained in the cakes was large in the sludge cake conditioned with chemical precipitation method (lime and ferric chloride) while it was nil in the sludge cake conditioned with heat precipitation method. 2) Application effect of phosphorus contained in the ashes was larger than that contained in the sludge cakes. Utilization percentage of phosphorus contained in the ashes was two times larger than that in the cakes. There was no difference in the utilization percentage of phosphorus between two kinds of ashes and between two kinds of ashes and between two kinds of conditioning for the sewage sludge cakes with different methods. 3) Application effect of potassium contained in the sludge cakes and in the ashes was indistinct because amounts of potassium uptake by oats were more than amounts of potassium by application of the materials. 4) Content of Mn, Zn, Pb, and Cd in oat plant was decreased and Cu was not different by ashes application compared with sludge cakes application. It was considered that heavy metals contained in the sewage sludge were transformed into insoluble form by incineration treatment.

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The effects of macro nutrient cations-K, Ca, and Mg-on uptake and toxicity to respiration of Cd in rice radicles were examined. After exposure to Cd, Cd uptake increased abruptly and the decrease of respiration rate occurred simultaneously for two or four hours, and then these tendencies stopped. Then the effects were examined after one-hour treatments. The uptake and the toxicity to respiration of Cd were reduced only in the presence of higher concentration of the cations than that of Cd. The decrease of respiration rate was entirely subject to the Cd content in radicles, independent of the cation treatments. Thus it could be inferred that the reduction of toxicity to respiration of Cd by the cations was due to the inhibition of Cd uptake by the cations. Ca inhibited Cd uptake most effectively among the cations. The combination treatments, K+Ca and K+Mg, were more effective than the K treatment. The divalent cations enhanced the ability of K to inhibit Cd uptake. Ca was much stronger than Mg in this effect. Though Ca played the important role in the Cd uptake as mentioned above, the content of Ca and its variation in radicles were least among the cations under the conditions that the uptake and toxicity to respiration of Cd were reduced.

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Relationships between glucosamine contents and nutritional disorder such as nitrogen, phosphorus, potassium, calcium, and zinc deficiencies were investigated with tomato, radish, barley, and corn seedlings. Isolation, identification, and determination of glucosamine were carried out under the following conditions: a) for isolation-ion-exchange column chromatography with Amberlite CG-120 and 0.3 N HCl as an eluate; b) for identification-paper electrophoresis detected by Elson-Morgan reaction; and c) for determination-HPLC with ISC-07/S 1504 (Shimadzu) and citrate buffer (pH 4.25) as an eluate detected by fluorometry. Results obtained were as follows: 1) Glucosamine was detected from each of the cold-water-soluble, SDS-soluble, and SDS-insoluble fractions. 2) Glucosamine contents were higher in potassium-deficient plants but almost the same in nitrogen-deficient plants compared with that of the control plants. 3) In all plant species tested, the percentage glucosamine in cold-water -soluble fraction over total glucosamine was decreased but that in cold-water-insoluble fraction was increased by nutritional disorder such as nitrogen and phosphorus deficiencies. From these results it could be speculated that glucosamine in SDS-soluble and SDS-insoluble fractions should be combined with structural materials in plant cells and its contents should not be drastically affected by the nutritional disorder.

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Muskmelon (Cucumis melo cv. Earl's Favourite) was grown on two kinds of soil bed (Ando sub-soil and alluvial soil) in a plastic house, in order to evaluate the effect of application rate or rice plant and the trial was conducted with four replications. The results obtained are summarized as follows. 1) In the early stage after transplanting, the plant growth on the Ando sub-soil was inferior to that on the alluvial soil, probably due to the shortage of phosphorus supply, but then recovered, resulting in the same degree of growth in the later stage. The compost application brought a good result; that is, the plant growth was generally increased with increasing the application rate in both soils. 2) The fruit weight and appearances estimated with net condition and spherical form were also increased with increasing the application rate in both soils. 3) The contents of total sugar and individual sugars such as glucose, fructose, and sucrose were higher in the fruit juice from the Ando sub-soil than in that from the alluvial soil. In both soils, these sugar contents were increased with increasing the application rate from 0 up to 1.0 kg/plant, but were significantly decreased at that of 2.0 kg/plant, as compared with the less-application rate. 4) The content of citric acid was lower in the fruit juice from the Ando sub-soil than in that from the alluvial soil. However, the decreasing tendency of this acid content with the application rate was observed in both soils. 5) The water-soluble pectin content in the fruit flesh from the alluvial soil was slightly higher than in that from the Ando sub-soil. This content was decreased with increasing the application rate in the former, but increased in the latter. 6) Taste trial indicated that the taste of fruits obtained from the highest application rate of 2.0 kg/plant was clearly inferior to that from the suitable one. This findings might be attributed to the higher sugar content as well as the lower citric acid and pectin content. 7) The phosphorus concentration in the plant tissues at harvesting time was lower in the Ando sub-soil than in the alluvial soil. The phosphorus and potassium concentration seemed to be increased with increasing the application rate. It was clarified, from the above-mentioned results, that the suitable application rate of rice straw compost to produce the high yield and quality of muskmelon was 1.0 kg/plant and Ando sub-soil was able to be used for the same bed soil as alluvial soil which was presently used for the muskmelon cultivation.

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Increase of I-131 concentration in wheat top was caused by the direct dry deposition of the I-131 in the air, not by the direct wet deposition of the rainfall, especially above 10 mm/day, by 7-35% compared with the preceding day. 2) In contrast to the wheat top, the increase of I-131 concentration in surface soil (0-0.5 cm) was caused by the direct wet deposition of I-131 in the rainfall, not by direct dry deposition of I-131 in the air. The increase rate of I-131 caused by rainfall was 9-90% compared with the preceding day. 3) It was estimated that the decrease of approximately 50% during the period from 9:00 on May 8 through 9:00 on May was caused by the volatilization of I-131 from the surface soil under the clear wheather and the high air temperature. 4) Fifty-seven % of I-131 deposited on the soil has been retained in 0-1.0 cm horizon; the remainder distributed in 1.0-7.5 cm horizon at June 20. On the other hand, about 100% of Cs-137 and Cs-134 has been retained in 0-1.0 cm horizon at June 20. 5) About 10% of I-131 was removed from wheat top by gentle washing with water. It was estimated that the same level percent of I-131 would be removed from wheat top by the rainfall. 6) It was confirmed chemically that 94.1% of I-131 in the rain water was in the form of iodate, 4.4% was iodide. This ratio was almost the same as the stable iodine in the rain water.

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Effects of NaCl on the absorption and the translocation of K, Ca, Mg, and P ions were examined with sugar beets (17 varieties), rice plants (16 var.) soy beans (28 var.), azuki beans (20 var.), and kidney beans (10 var.). Plants were grown in culture solution supplied with (40-120 mM) NaCl or without NaCl. The results obtained are summarized as follows: 1) Absorption of P was not suppressed by the addition of NaCl in all plants tested. 2) In sugar beets and rice plants, concentrations of K, Ca, and Mg ions in tops and whole plants were lower in NaCl treatments than in each control. However, in 3 legumen the concentrations of the cations in the leaves and whole plants were higher with NaCl treatments than in each control except for Mg concentration in leaves and/or whole plants of soy beans and kidney beans. 3) It was suggested that the absorption and the translocation of K, Ca, and Mg ions were strongly affected by Na/Cl molar ratio in each organ or whole plants, upon the addition of a large amount of NaCl to the culture solution. Taking the Na/Cl ratio more than 1 (whole plants and tops of sugar beets, stems of legumen), the concentrations of the cations were lower with the NaCl treatments than in each control in order to suppress the excess of the cations. In the case of lower than 1(whole plants and leaves of legumen), the cation concentrations were higher with NaCl treatments than in each control in order to neutralize the excess of Cl ion. Which cations will be more activity absorbed and translocated than control by the addition of NaCl to the medium might be determined by the ion composition of culture solution and the ion-selectivity of whole plants and their organs.

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In three 30 a paddy fields of Gravelly Gley Upland Soils, main underdrains and the pipes for draining the surface water and penetration water were constructed. As the soils of this paddy field contained adequate amount of sand and gravel, numbers of soil cracks and water permeabilities of soils were increased during cultivating soybean, and soybean growth and yield were good. Both soil drainage and field maturing process in this Gravelly Gley Upland Soil had advanced to about 30 cm depth. In 30 a paddy field of Fine-Textured Gley Upland Soil, in addition to the construction of main of 20 cm in depth were dug with 5 m interval to accelerate the drainage of surface water. Because the soil had high clay content (LiC), and massive layers, the water permeability and formation of soil cracks were not improved, which caused injuries to the planted barley owing to the excess moisture. It can thus be concluded that the conversion of paddy field of Fine-textured Gley Upland Soil to matured upland field was considerably difficult without intensive drainage system.

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