• Korean Journal of Soil Science and Fertilizer
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• v.33 no.3
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• pp.139-144
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• 2000

This study was conducted to obtain the basic information to increase the practical use of soil survey data through the subdividing of valley shapes with soil sequences due to different parent rocks, and to study the relationship between the valley shapes and parent rock. The various rocks such as sedimentary(gray shale and sand stone) and igneous rocks(granite, granite gneiss and andesite porphyry) which are the major parent rocks in Yeongnam area were investigated. The characteristics of valleys formed and the kinds of soils derived from different rocks were analysed by using aerial photographs and topographical maps scaled 1:5,000. The rill density in igneous rock area was as high as 40. But the rill bifurcation ratio of first order stream was higher in the sedimentary than the igneous rocks except granite area. The mean slope of valleys in igneous areas was about 8%, which was higher than that of the sedimentary areas. The variability of valley width in the complexly metamorphosed rock, such as granite gneiss, and andesite porphyry, was greater than in sedimentary and in granite rocks. Based on the variability of valley widths and valley slopes, it was possible to classify the valleys into two types. The "Uterus-shaped valleys" had wide variability of valley width and were located in the areas of granite gneiss and andesite porphry rocks. while the "Roots-shaped valleys" had narrow variability of valley width and were located in the sedimentary areas. "Uterus-shaped valleys" were typified by having land forms of mountain foot slopes and alluvial fans, and the soil drainage sequences also had complexities. So that, we concluded that the variability of valley width and valley slopes was associated with kinds of parent rocks and metamorphism which influences soil sequence and characteristics.

• Journal of Sericultural and Entomological Science
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• v.22 no.1
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• pp.26-45
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• 1980

Silk protein is synthesized in the silkgland of silkworm, Bombyx mori L. It is evident that silk productivity is one of the high heritable characters from the genetical aspects. It is also changed with the environmental circumstances. With this regard, this paper dealt with the varietal patterns of silkgland development and the factors concerning to the silk productivity of silkgland of silkworm by the synthesis of nucleic acids, profiles of amino acids and histological basis, using the eight parent silkworm varieties and their F$_1$ hybrids. 1. The weight of silkgland per larva increased proportionally in the F$_1$ hybrids which were crossed between longer silk yielding varieties. The silk content to the weight of the silkgland was higher in the longer silk yielding varieties than that in the shorter silk yielding varieties. 2. It was observed that the morphological changes of nuclei took place in the posterior silkgland cells with the larval development of the 5th instar. In varietal aspect, Jam 107 and Jam 108, longer silk yielding varieties, showed more branches in nuclei than the $N_2$ and $C_{60}$ which were shorter yielding ones. 3. It was observed that there was a high correlation between RNA content per unit weight of silkgland on the 6th day stage of 5th instar and silk productivity both in the parents and their F$_1$ hybrids. 4. RNA and DNA synthesis brought about thirty percent increase in the posterior silkgland of the longer silk yielding varieties during the 2nd day to the 4th day stages of the 5th instar, when compared with those in the posterior silkgland of the shorter silk yielding varieties. 5. RNA/DNA ratio in the posterior silkgland on the 2nd day and 4th day stages of the 5th instar was more increased in the longer silk yielding varieties than the shorter silk yielding varieties. 6. It was shown that DNA content for the longer silk yielding varieties came to be 374$\mu\textrm{g}$ per larva in the posterior division of silkgland on the 4th day stage of 5th instar, whereas it was 199$\mu\textrm{g}$ per larva for the shorter silk yielding varieties. 7 There was 34.8％ Alanine, 22.8％ Glycine, 9.1％ Serine and 7.3％ Tyrosine in the posterior division of silkgland as major amino acids. It is noticed that there was a little differences between the amino acids composition of posterior silkgland and silk fibroin. 8. There was some differences in the amino acids composition of posterior silkgland between pure lines and their hybrids. Glycine, Serine and acidic amino acids, essential to silk formation, seemed to be increased in the F$_1$ hybrids, whereas other amino acids such as Valine, Iso-leucine, Leucine, Lysine. Phenylalanine, Histidine and Arginine were reduced. 9. The content of Glycine, Alanine and Serine in the posterior division of silkgland was elevated in the longer silk yielding varieties than the others. Consequently. these three amino acids in the posterior silkgland seemed to be related to the silk yielding ability in the longer silk yielding varieties.s.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.3
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• pp.154-162
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• 2003

This study was conducted to investigate the effects of tile drain on Physicochemical properties and crop productivity of soils under plastic film house for three years (1999 - 2001). Tiles (${\Phi}100mm$ PVC pipe) were established at 50-60 cm depth with 1 m, 2 m, and 3 m intervals in Gangseo silt loam soil under 2W-type plastic film house. Cropping system was a pumpkin-pumpkin in the first year, a cucumber-spinach-crown daisy-spinach-young radish in the second year, and a green red pepper-tomato-spinach in last year, with conventional fertilization and drip or furrow irrigation by groundwater pumping. Bulk density and soil hardness of plot with tile drain were lower than those of control (plot without tile drain). Soil water content was also lower in tile drain plot than in control regardless of soil depth, and decreased at narrower interval and longer distance from tile in the same plot, thus suggesting that water flow and density of tile drain plot was higher than those of control. Rhizosphere of spinach, a final crop of third year, was expanded more than 2 cm due probably to improvement of soil physical properties caused by tiles establishment. Electrical conductivity (EC) of topsoil decreased from $1.22dS\;m^{-1}$ to $0.82dS\;m^{-1}$ by tile drain system, and the extent of EC decrease was different with season: higher in spring and lower in summer and autumn. The $NO_{3^-}-N$ concentration in topsoil decreased, from $200mg\;kg^{-1}$ to $39mg\;kg^{-1}$. The effect of tile drain on crop yield varied with crops. Average crop productivity obtained in tile drain plot than that of control crop: 18.2% in 2 m interval, 14.2% in 3 m interval, but lower 0.2% in 1 m interval.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.3
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• pp.353-360
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• 2011

In order to develop the application method of pig compost (PC) and liquid manure (LM) for whole crop barley cultivation, experiments were conducted at Munpo series (coarse loamy, mixed, nonacid, mesic family of Typic Fluvaquents) soil in Gyehwa-reclaimed land, six plots, a LM applied rate as N% ; non-application, chemical fertilizer (CF)100, 100, 50+50, 50+CF50 and (PC30+LM40)+LM50 as basal and additional fertilizer. $NO_3^-$-N content in soil was decreased as along with the growth of plant, highest in LM100% as basal fertilization at early growth stage and highest in (PC30%+LM40%)+LM40% and CF100% at last growth stage. Amount of $NO_3^-$-N and $NH_4^+$-N in soil was high in (PC30%+LM40%)+LM40% and CF100% of top soil but in subsoil significant difference was little in all treatment. Amount of OM, $A_V.P_2O_5$, T-N, exchangeable Ca and Na in soil was higher (PC30%+LM40%)+LM40% than non-application after harvest. Amount of nutrient uptake in plant was higher in CF100% and split application of LM than LM 100% application. Nitrogen utilization rate was in the order of CF100% >LM50%+LM50%=LM50%+CF50%>(PC30%+LM40%)+LM40% >LM100%. The yield of whole crop barley in (PC30%+LM40%)+LM40% and CF100% was 3.2 times more than in non-application ($309kg\;10a^{-1}$). Feed values such as crude protein and TDN was increased 1.0% ~ 1.4% in LM as split application than basal 100% treatment. Accordingly, in order to increase yield of a whole crop barley with application PC+LM in reclaimed land treat split application rather than to treat LM 100% into the land.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1258-1263
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• 2011

This study was conducted to reclassify Asan series based on the second edition of Soil Taxonomy and to discuss the formation of Asan series distributed on the rolling to hilly areas. Morphological properties of typifying pedon of Asan series were investigated and physico-chemical properties were analyzed according to Soil survey laboratory methods manual. The typifying pedon of Asan series has dark yellowish brown (10YR 4/4) gravelly loam Ap horizon (0-18 cm), strong brown (7.5YR 5/6) gravelly clay loam BA horizon (18-30 cm), red (2.5YR 4/6) gravelly clay loam Bt1 horizon (30-52 cm), red (2.5YR 4/8) gravelly clay loam Bt2 horizon (52-98 cm), and red (2.5YR 4/8) gravelly clay loam C horizon (98-160 cm). The typifying pedon has an argillic horizon from a depth of 30 to 98 cm and a base saturation (sum of cations) of less than 35% at 125 cm below the upper boundary of the argillic horizon. It can be classified as Ultisol, not as Inceptisol. It has udic soil moisture regime, and can be classified as Udult. Also that meets the requirements of Typic Hapludults. It has 18-35% clay at the particle-size control section, and has mesic soil temperature regime. Therefore Asan series can be classified as fine loamy, mesic family of Typic Hapludults, not as fine loamy, mesic family of Typic Dystrudepts. Asan series occur on rolling to hilly areas in residual materials derived from granite gneiss, schist, and gneiss rocks. They are developed as Ultisols with clay mineral weathering, translocation of clays to accumulate in an argillic horizon, and leaching of base-forming cations from the profile for relatively long periods under humid and temperate climates in Korea.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.970-976
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• 2011

Strip tiller equipment was developed to reduce soil erosion in the slope land for highland agricultural area. The equipment consisted of 4 rows strip tillage device and fertilizer applicator. The field was tilled in 10 cm width and in 10 cm depth by the equipment, of which tilled surface was 16.7% of full-width tillage. The working time and fuel consumption of the equipment were $3.8hours\;ha^{-1}$ and $24.4L\;ha^{-1}$ respectively, which were 59% and 74% less than those of the conventional tillage. Fertilizer efficiency of the equipment in cultivation of Chinese cabbage was 1.7, 1.6 and 1.5 times higher in nitrate, phosphorous and potassium respectively, than conventional tillage. When the equipment was used after covering of rye residue, the quantity of runoff was 49~67% lower than the conventional tillage. And the quantity of soil loss were 1.3 and $0.2Mg\;ha^{-1}$ at right after and 30 days after planting of Chinese cabbage respectively, while 11.5 and $4.1Mg\;ha^{-1}$ in conventional tillage. In conclusion, the strip tillage equipment developed in this study can be applicable to slope land, so that soil loss of 90% can be reduced.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1272-1278
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• 2011

This study was conducted to reclassify Cheongweon series based on the second edition of Soil Taxonomy and to discuss the formation of Cheongweon series distributed on broad continental alluvial plains. Morphological properties of typifying pedon of Cheongweon series were investigated and physico-chemical properties were analyzed according to Soil survey laboratory methods manual. The typifying pedon of Cheongweon series has dark grayish brown (2.5Y 4/2) silt loam Ap horizon (0~18 cm), dark grayish brown (2.5Y 4/2) silt loam BA horizon (18~30 cm), dark yellowish brown (10YR 4/6) silty clay loam Bt1 horizon (30~60 cm), strong brown (7.5YR 4/6) silty clay loam Bt2 horizon (60~91 cm), brown (10YR 4/4) silt loam BC horizon (91~104 cm), and mottled (7.5YR 4/6, and 7.5YR 5/2) silt loam C horizon (104~160 cm). The typifying pedon has an argillic horizon from a depth of 30 to 91 cm and a base saturation (sum of cations) of 35% or more at 125 cm below the upper boundary of the argillic horizon. It can be classified as Alfisol, not as Incceptisol. It has udic soil moisture regime, and can be classified as Udalf. Also that meets the requirements of Hapluadalf. It has anthraquic condition, and keys out as Anthraquic Hapludalf. That has fine silty textural family, and has mesic soil temperature regime. Therefore Cheongweon series can be classified as fine silty, mixed, mesic family of Anthraquic Hapludalfs, not as fine silty, mixed, mesic family of Fluvaquentic Epiaquepts.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.6
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• pp.954-961
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• 2010

Ground-based remote sensing can be used as one of the non-destructive, fast, and real-time diagnostic tools for quantifying yield, biomass, and nitrogen (N) stress during growing season. This study was conducted to assess biomass and nitrogen (N) status of paddy rice (Oryza sativa L.) plants under N stress using passive and active ground-based remote sensors. Nitrogen application rates were 0, 70, 100, and 130 kg N $ha^{-1}$. At each growth stage, reflectance indices measured with active sensor showed higher correlation with DW, N uptake and N concentration than those with the passive sensor. NIR/Red and NIR/Amber indices measured with Crop Circle active sensors generally had a better correlation with dry weight (DW), N uptake and N content than vegetation indices from Crop Circle passive sensor and NDVIs from active sensors. Especially NIR/Red and NIR/amber ratios at the panicle initiation stage were most closely correlated with DW, N content, and N uptake. Rice grain yield, DW, N content and N uptake at harvest were highly positively correlated with canopy reflectance indices measured with active sensors at all sampling dates. N application rate explains about 91~92% of the variability in the SI calculated from NIR/Red or NIR/Amber indices measured with Crop Circle active sensors on 12 July. Therefore, the in-season sufficiency index (SI) by NIR/Red or NIR/Amber index from Crop Circle active sensors can be used for determination of N application rate.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.5
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• pp.393-398
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• 2009

This study was conducted to reclassify Yongdang series based on the second edition of Soil Taxonomy : A Basic System of Soil Classification for Making and Interpreting Soil Surveys. Morphological properties of typifying pedon of Yongdang series were investigated and physico-chemical properties were analyzed according to Soil Survey Laboratory Methods Manual. The typifying pedon of Yongdang series has dark reddish brown (5YR 2/3) silt loam Ap horizon (0~14 cm), dark brown (7.5YR 2/3) silt loam BA horizon (14~32 cm), dark brown (7.5YR 2/3) clay loam Bt horizon (32~57 cm), dark yellowish brown (10YR 4/6) silty clay loam Btx1 horizon (57~110 cm), and dark yellowish brown (10YR 4/6) silty clay loam Btx2 horizon(more than 110 cm). That occurs on gently sloping lava plain and is derived from baslt materials. The typifying pedon has an argillic horizon from a depth of 32 to more than 110 cm and a fragipan from a depth of 57 to more than 110 cm. That has a base saturation (sum of cations) of 35% or more at 75 cm below the upper boundary of the fragipan. That can be classified as Alfisol, not as Inceptisol. The typifying pedon has udic soil moisture regime, and can be classified as Udalf. That has a fragipan with an upper boundary within 100 cm of the mineral soil surface, and keys out as Fragiudalf. Also that meets the requirements of Typic Fragiudalf. That has 18% to 35% clay at the particle-size control section, and has thermic soil temperature regime. Yongdang series can be classified as fine loamy, mixed, thermic family of Typic Fragiudalfs, not as fine loamy, mixed, thermic family of Aquic Eutrudepts.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.1
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• pp.85-94
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• 2007

To determine the influence of food waste compost (FWC) application on paddy soil, FWC was applied to the paddy soil and then compared with farmer's practice as to the effects on rice and soil environment. Initially, pig manure compost (PMC) had high content of phosphorus ($15g\;kg^{-1}$) and potassium ($23g\;kg^{-1}$), while FWC had high content of total nitrogen ($13g\;kg^{-1}$) and salinity ($18.5g\;kg^{-1}$). Comparison was also made between chemical fertilizer and FWC use as a trial in the paddy field under the clay loam and sandy loam soil. In the panicle formation stage, chemical fertilizer application was proper in clay loam while PMC application was proper in sandy loam. However, chemical fertilizer produced higher yield compared to compost treatment, both on clay loam and sandy loam with 20~25% and 17~19%, respectively. The lower yield in sandy loam maybe due to slow mineralization of compost such that the crop did not effectively use it. Organic matter content in paddy soil after experiment was higher in FWC and PMC plots compared to that in chemical fertilizer plots. But the other soil properties were comparable. Therefore, the FWC compost had little effect on soil when it use as a trial in paddy field. Likewise, after the application of FWC as a trial, analysis of nitrate nitrogen and ammonium nitrogen in the surface water and 60 cm depth of paddy soil water nine days after planting was done. Results revealed that concentration of ammonium nitrogen was similar to irrigation water while nitrate nitrogen concentration was not detected, and hence did not contribute to water pollution. It is concluded that the application of FWC in the paddy field had not affected on environmental pollution in the paddy field. But its use as compost during rice culture reduced yield quantity. Such study should include selection of compost material, amount and method of compost application.