• KSBB Journal
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• v.15 no.2
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• pp.201-207
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• 2000

The traditional ripening method of clay was analyzed. An advanced refining method of clay using enrichment cultures of iron r reducing bacteria was developed. After the traditional ripening, the whiteness of the clay was increased due to removal of | iron impurities by inhabitant dissilmaltien with iron reducing bacteria. Other characteristics of the refined clay such as v viscosity, plasticity, and strength were also improved by iron reducing bacteria. An advanced method of clay refinement with a anaerobic enrichment cultivation of iron reducing bacteria supplemented with an extra carbon source such as glucose was s suggested. When the clay was treated by the advanced method. the refinement time could be reduced to 1/6 of that r required by the traditional method. The physical properties of the refined clay by the advanced method were better than t those of the traditionally refined clay.

• Culinary science and hospitality research
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• v.6 no.3
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• pp.357-371
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• 2000

Changes of Microflora, enzyme activity, and contents of several taste compounds in traditional Kanjang(Korean Soy Sauce) with the variation of fermentation jars and Meju(fermented soybean brick)concentration were studied. Substitution possibilities of clay jar with glass jar and improvement possibilities of taste and nutritional value with increased Meju concentration were examined. (1) Aerobic bacteria and lactic acid bacteria were enumerated during fermentation and ripening period. But yeast and molds were hardly isolated. The number of viable cells showed small changes during fermentation and ripening period. (2) Isolated Aerobic bacteria were identified as Bacillus subtilis, Bacillus lichenformis, and lactic acid bacteria were identified as Lactlbacillus lactis lactis and lactobacillus brevis. (3) The activities of $\alpha$-amylase and $\beta$-amylase increased during fermentation period, but did not show any trend by fermentation jars or Meju concentrations. Protense activity showed small difference among four samples, and increased during the fermentation period.

• KSBB Journal
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• v.15 no.2
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• pp.208-213
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• 2000

Using three types of porcelain clays such as White, Blue, and Yellow clays, which were used as raw materials for Bae씨a, C Chungja, and common porcelains, the biological refinement by an enrichment culture of iron reducing bacteria was studied. | In the biological clay refining, amounts of leached iron increased as increasing sucrose $\infty$ncentration, which was s supplemented as a carbon and electron donor source for cell growth and iron reduction. Total amounts of the leached iron a and specific rate of iron reduction were dependent on the types of the clay. Strength and chromaticity of refined clays which a are important properties required for porcelain clays were improved as increasing sucrose concentration. The degree of s shrinking, however, did not changed. the redness among the chromaticity of refined clays is favorably reduced through the r ripening by the iron reducing bacteria. Considering iron removal efficiency and the change of physical properties, the optimal c concentration of sucrose was 4%(w/w) in the clay.

• Korean Journal of Agricultural and Forest Meteorology
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• v.2 no.4
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• pp.148-155
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• 2000

The typhoon and flooding injury in rice were investigated both the region of downpour at the middle of August and the region of typhoon 'Yanni' at the late of September, 1998 in Kyongbuk provincial of Korea. More than 10% of rice stem were buried by soil inundation, the heading was delayed and the high node tiller was brought out. Yield components were deteriorated and yield was reduced. As the clay in the muddy water was attached on grains of rice, the yield was greatly reduced by reason of low grain filling ratio and polished rice ratio. The injury of muddy water was less at yellow ripening stage than at early ripening stage. On the other hand, the muddy water injury was reduced by the fungicide 'Benomyl' and 'Daconil' treatments. The degree of lodging according to varieties and ripening stages was not made a great difference, while the lodging was mainly occurred in the early transplanting time. In a week after lodging, viviparous spikes were occurred in almost all varieties, the degree of viviparity was shown highly in order of early maturing, middle maturing and late maturing varieties in the field as well as in laboratory test. The viviperous spikes were greatly occurred in the lodging toward hill space within row than row space because the more grains were touched on the ground.

• Food Science and Biotechnology
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• v.14 no.1
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• pp.82-88
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• 2005

Ethnic Korean onggi earthenwares were fabricated using different clay formulations and glazing treatments. Their permeability properties against oxygen, carbon dioxide, and moisture were measured at $20^{\circ}C$ and examined from the aspect of food preservation. Onggi walls consisted of micropores that offered higher gas and moisture permeation rates when compared with other food packaging materials. Earthenware walls were unique in having $CO_2/O_2$ permeability ratios of 0.60-1.00. Gas and moisture permeabilities were lower, with wall structure having lower porosity and surface glazing. Results revealed onggi jar packages of grape fruits could attain wide range of $O_2$ and $CO_2$ concentrations. Onggi containers present good opportunity to obtain optimum packaging conditions for respiring or ripening products, depending on commodity type.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.3
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• pp.221-224
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• 1999

A field experiment was carried out to observe the weed control effects of vetch and to evaluate vetch characteristics on clay loam soil in no-till direct-sown rice-vetch cropping systems. The effects of weed control, forage productivity, and N content of vetch plants were investigated. With the progress of plant growth, density of Chinese milk vetch (Astragalus sinicus L.) gradually decreased, but densities of foxtail and other weeds decreased steeply due to the depression by the over-shaded vetch canopy in a no-till direct-sown rice-vetch cropping paddy field. The vetch density in tillage systems was lower than in notillage cropping systems. Lower vetch density occurred with an increase in foxtail density and other weeds. Weed control effect increased by the progress of vetch growth, which indicated that the vetch canopy over-shaded the weeds. Vetch straw was degraded rapidly submergence after with water at the time of wet sowing of rice. Early harvesting of vetch seed resulted in lower seed germination. To acquire enough seedlings without re-sowing, the harvesting of seed should be delayed at least 28 days after the flowering stage in order to ensure the vetch population is sustainable in a no-till direct-sown rice-vetch cropping system. In order to improve the survival of vetch plants, vetch seeds should germinate from the heading .stage to before the full-ripening stage of rice plants. To enhance the percent of over-wintering survival, vetch seeds should germinate no later than the end of October in southern Korea. The dry weight of vetch plants increased with the progress of vetch growth until the flowering stage but N content decreased for 30 days from before the flowering stage (2.9%) until the ripening stage (1.8%). We concluded that Chinese milk vetch could have an effect on weed control before the flowering stage, sustainability without re-sowing of seed annually, and effective green manure for rice pre-crop in no-till direct-sown rice-vetch relay cropping systems.

• Magazine of the Korean Society of Agricultural Engineers
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• v.13 no.3
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• pp.2322-2341
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• 1971

The studies were conducted to determine the methods of irrigation control which is not only able to save the irrigation water as a adaptable measures for the insufficient irrigation water and the drought but also increase the yields of rice, in the paddy field which shows over percolating tendency through the couple years of 1968 and 1969 at Suwon. These experiments were carried with late maturing rice variety, Norim No. 6 and the major treatments in this experiments were filling the clay under surface soil, periodic irrigation and lining the Vinyl under the surface soil and three replicated completely randomized design was employed. Results obtained will be summarzed as follows. 1. Through the couple years, the plots tilled the clay under 15cm of the surface soil saved the irrigation water by 364% to 45% and 78% to 88% respectively. Particulary, the plot of filling the clay with 9cm thick under 15cm of the surface soil, saved the amount of irrigation water by 45% to 88% and also increased yields by 12% to 20% through the couple years. 2. The plots in which amount of 40mm of irrigation water is irrigated periodically from 5 to 8 days at the stages of tillering and ripening, saved theamount of irrigation water by 41% to 55% and also increased yields by 10% to 16% respectively through the couple years. 3. The plot lined the Vinyl under 15cm of the surface soil, saved the amount of irrigation water by 75% to 88% in accordance with the size of hole. The plot of lining the Vinyl with $3cm/m^2$ hole yielded almost same as the check plot, but in the case of lesser hole than above yielded less. 4. The plots inserted the Vinyl paper in 57cm depth and with 6cm height from the soil surface around the plot to prevent the ridge percolation reduced the amount of percolation by 25% to 33%. 5. The plot filled the wheat straw with 6cm thick under 15cm of the surface soil increased yields by 30% in former year but opposite results were gained in later year. 6. Generally, yields and yield components such as number of spikes of spikes per hill and number of grains per spike were decreased in 1969. These faots are considered to depend upon the rainy and cold weather in the stages of vigorous tillering and less sunshine in the stages of ripening. 7. The variation of characters among the plots will be summarized as follows. (1) Tallerplant height was found in the plots of clay filling and irrigation control. (2) longer culm length and higher yields were founds in the plots filled the clay with 9cm thick and controled the irrigation periodically froir 7 to 8 days. (3) Length of spike increased generally with yields but opposite tendency was found also. (4) Number of spikes per hill increased with yields in the plots of irrigation control. (5) Number of grains per spike increased with yields in the plots filled the clay with 9cm thick and controled irrigation periodically from 5 to 8 days. (6) Tendency of variation of 1000 grain weight is similar to Number of grains per spike. (7) Percentage of complete grains increased in the plot of clay filling and irrigation control.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.6
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• pp.499-505
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• 1992

This experiment was carried out to find out the optimum application method of slow-release fertilizer under different soil textures, clay loam(Deogpyeong series), sandy loam (Gangseo series) in the southern region(Milyang, Kyeongnam) of Korea. The fertilizers used were Chosun slow-release fertilizer(silicate latex coated fertilizer: N-P$_2$O$_{5}$-K$_2$O=18-12-13) and Meister 15 (thermoplastic resin coated fertilizer : N-P$_2$O$_{5}$-K$_2$O=14-14-14). The two whole basal application methods such as side band placement at transplanting time of rice plant(cv.Donghaebyeo) and incorporation with soil as basal were tested. The released amount of ammonium nitrogen from the soils for 4 days submerged was 95ppm in sandy loam and 60ppm in clay loam. The greenish degree of rice leaf was higher at the whole plow layer placement method than the others. The nitrogen efficiencies of the fertilizers were Meister 15 > convention > Chosun in order and between the application methods were similiar. The growth status was better at the whole plow layer placement application method of Meister 15 regardless of soils and seedling ages. The ripening ratio was increased at slow-release fertilizer application, and between application methods, whole plow layer placement was lower because of lodging damage. The yield in clay loam soil showed a significant difference between the ferilizers, but there were slight differences between the application methods and fertilizers in sandy loam soil. As a result, the slow-release fertilizer, Meister 15, applied at the whole layer showed a good rice growth and seemed a plausible fertilizing method.

• Korean Journal of Soil Science and Fertilizer
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• v.22 no.3
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• pp.180-190
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• 1989

In order to obtain basic information on soil inprovement and management of two reclaimed paddy soils, Munpo and Pori series, this study was carried out by investigating the change of physico-chemical and soil mechanical properties. 1. In the Munpo series, the contents of salt in the soil and ground water before paddy rice transplanting at 6 years after reclamation were 0.60 and 1.84%, respectively, and the safty cultivation of paddy rice was possible after 20 years, while that of the Pori series was after 12 years. 2. In the Munpo series, the change of the soil particle size according to the ages after reclamation showed negative correlation with sandy contents, but clay contents had positive correlation both in the surface and subsurface soils. The pori series showed reverse tendency. 3. Between the N-value and Atterberg limits and the ages showed negative correlation in both Munpo and Pori series, but clay-activity showed positive. Arid the cole values showed positive correlation in the Munpo series, but negative in the Pori series. 4. Cone penetrating resistance in the surface of the Munpo series after 6 years of reclamation was 62.9, after 20 years 24.5 and $16.7kg/cm^2$ in 15cm of soil depth at depth of 22.5cm after 27 years. In the Pori series, it was $3kg/cm^2$ at 15-20cm of soil depth after 12 years and it used after being creation of hard pan layer after 23 years. 5. Change of the clay minerals by the different year after accomplishment of tidal reclamation did not show. The major clay minerals were illite and kaolinite, and accessory clay minerals were montmorillonite and vermiculite in both Munpo and Pori series.

• Korean Journal of Soil Science and Fertilizer
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• v.10 no.4
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• pp.235-243
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• 1978

A field experiment was conducted to confirm the effect of phosphorus, calcium silicate and different kinds of organic matter to a red-yellow heavy clay textured paddy soil, developed on alluvial terrace. 1. The yield response of phosphorus was very high in both Tongil (Indica x lap.) and Jinheung (Japonica type) varieties. Twenty percent of yield increase with 56kg $P_2O_5$ per 10a. 2. Yield increase by application of phosphorus was closely resulted from increase of tillers per plant. The increases of tillers per plant as observed at harvesting stage by phosphorus fertilization were 3.6 tillers in Tongil, 1.9 in Jinheung, while ripening ratio adversely was decreased 4% in Tongil and increased 3% in Jinheung. 3. High correlation between P content and yield was found at earformation and heading stages. The content of P in rice plant necessary to produce maximum yield in this soil was 0.8 percent at earformation stage. 4. The effect of silicate was not significant for Tongil but was obvious for Jinheung, and the effect of compost and rice husk was also significant for Jinheung. 5. Addition of silicate and lime to phoshorus treatment decreased the nitrogen content of rice plant, especially in Tongil. Accordingly, significant responses of silcate and lime seems be appeared by increasing the rate of nitrogen application.