• Korean Journal of Plant Resources
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• v.31 no.4
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• pp.384-395
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• 2018

This study was carried out to investigate the environment factors including community structure and soil characteristics in the wild habitats of Cephalotaxus koreana, and offers the basic information for habitats conservation and restoration. Most of the wild habitats were located at altitudes between 148~835 m with inclinations ranged as $12{\sim}32^{\circ}$. The average soil pH was 4.7~5.9, soil organic matter was 5.72~15.99%, cation exchange capacity was $14.1{\sim}19.9cmolc/kg^{-1}$ and exchangeable $K^+$, $Ca^{2+}$, $Mg^{2+}$ was 0.25~0.48 cmolc/kg, 0.79~6.68 cmolc/kg, 0.31~1.73 cmolc/kg, respectively. The dominant species of tree layer were found to be dominated by Quercus dentata in Jekbo-san (C1), Acer pictum in Bogae-san (C2), Acer pseudosieboldianum in Geumwon-san (C3), Q. serrata in Jiri-san (C4), Zelkova serrata in Baegun-san (C5), and Q. acutissima in Duryun-san (C6). The Species diversity (H') was 0.854~1.234, evenness (J') was 0.654~0.993, and dominance (D) was found to be 0.067~0.346. Correlation coefficients analysis based on environmental factors, community structure and value of species diversity shows that growth of Cephalotaxus koreana is correlated with species diversity and evenness. This result show that Cephalotaxus koreana habitats located in mature stands.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.1
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• pp.1-7
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• 2001

Total upland area for cultivating the vegetable crops in the Alpine soils of Northeastern South Korea has been extending its limit to meet the increasing demand of vegetable food in recent decades. About 70% of these alpine soils are located in over 7% of the slope and most of vegetable crops have been cultivated intensively without practicing the best management systems. Thus, soil erosion and continuous cropping system have degenerated the soil fertility and shown detrimental effects on water quality. We initiated an intensive and extensive investigation to characterize the fertility problems encountered in these uplands. Objectives of this paper were to characterize the fertility status in the Alpine soils cultivated with vegetable crops for many years and to provide the recommendations for adequate soil management measures including fertilization and erosion control. Soils in general have good drainage with textural classes of loam or sandy loam. Their topographical characteristics tended to lead them to shallow plow layers, and the steepness of the terrain created erosion hazard. Of the soils examined, about 11% of uplands over 30% gradient was found in need of an urgent reforestation. A high content of gravel and firm hardness of soil attributed to inhibit the utilization of farm machinery and plant-root development. The average soil pH 5.6 was slightly low relative to pH 5.70 of the national average. Organic matter content was high compared with 2.0% of national average, but decreased with the prolonged cultivation periods. Available $P_2O_5$ concentration was unusually high due to the consequence of over dose application with chemical and organic fertilizers. Exchangeable cations as Ca, Mg, and K were appeared to be decreased in these regions with prolonging the cultivation periods. There were no significant differences in cation exchange capacity (CEC) and electrical conductivity (EC) among locations. Heavy metal contents were mostly lower than the threshold of danger level designated by Soil Environment Conservation Law of South Korea. Results indicated that a proper countermeasure and the best management practice should be immediately implemented to conserve the top soil and fertility in the Alpine regions.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.6
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• pp.357-365
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• 2006

The investigations were conducted to find out the situation of fertilizer use and the contents of soil chemical components on summer vegetable crops at 791 farmers' upland fields located in the parts of Gangwon-do, Gyengsangbuk-do and Jeollabuk-do of alpine area. Major vegetable crops were potato, Chinese cabbage, radish, carrot, onion, and cabbage. From the location surroundings cultivated alpine vegetable crops, the orders were Gangwon-do>Gyeongsangbuk-do>Jeollabuk-do part in the sizes of a fie1d area and the height above sea level, and Jeollabuk-do>Gyeongsangbuk-do>Gangwon-do part in the slope degrees. The soil texture was of wide distribution on sandy loam soil for Gangwon-do(76%) and Jeollabuk-do part(64%), and 1oam(42%) and sandy loam soil(35%) for Gyeongsangbuk-do part. From the numbers of investigated fields, the distribution of slope degree was wider than those of height above sea level in relation to location surroundings. The upland soils of 785 fields cultivated vegetable crops were sampled at 0~15 cm of top soil before seeding or transplanting and analyzed. On an average, pH, organic matter, available phosphate and exchangeable potassium, calcium, magnesium of soil were 5.7, $27.6g\;kg^{-1}$, $765mg\;kg^{-1}$, $1.16cmol_c\;kg^{-1}$, $6.1cmol_c\;kg^{-1}$, and $1.6cmol_c\;kg^{-1}$, respectively. The average cation exchange capacity(CEC) of 120 sites in Gangwon-do part was $9.2cmol_c\;kg^{-1}$. The content of organic matter, exchangeable potassium, exchangeable calcium and exchangeable magnesium was higher, while that of available phosphate was lower with slope degrees. And the content of major chemical components in carrot soil was lower in comparison with other crop soils. The average levels of N, $P_2O_5$, $K_2O$, livestock manure and lime fertilizer of 785 Belds applied by farmers were 335, 198, 244, 12,680 and $1,750kg\;ha^{-1}$, respectively, for summer vegetable crops in alpine area. The average amounts of $N-P_2O_5-K_2O$ fertilizers applied by farmers in 785 Gelds of vegetable crops were higher 1.7~2.0-4.2~7.0-1.4~2.0 times on potato, 1.4~1.6-4.6~8.3-3.5~4.2 times on Chinese cabbage, and 1.2~1.3-4.2~7.2-3.0~3.61 times on radish than the rates of NPK fertilizers based on soil testing for each crop.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.6
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• pp.981-986
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• 2010

This study was carried out to investigate the effects of fertilizer and organic resource annual dressing for 30 years of Jeonbug series (silt loam) on soil properties and rice N uptake in paddy field soil. In the study field, treatments including control (NPK), NPK+rice straw, NPK+rice straw compost and nitrogen fertilization levels at 0, 100, 150, 200, 250 kg $ha^{-1}$ have been imposed for 30 years. Soil hardness and bulk density decreased from 15.7 mm and 1.381 Mg $m^{-3}$ in the control to 12.5 mm and 1.244 Mg $m^{-3}$ in NPK+rice straw compost treatment, respectively, indicating improvement of soil physical conditions such as porosity. Co-application of straw compost with NPK also result in a better chemical properties than NPK alone as it increased available phosphate (from 96 to 133 mg $kg^{-1}$), available silicate (from 81 to 116 mg $kg^{-1}$), and cation exchange capacity (from 9.8 to 11.4 $cmol_c\;kg^{-1}$). Soil organic matter concentration of top soil (0 to 7.5 cm in depth) was higher in NPK+rice straw and NPK+rice straw compost than in control. Fertilizer N uptake amount was much higher in NPK+rice straw (nitrogen fertilization level; 250 kg $ha^{-1}$) and NPK+rice straw compost (nitrogen fertilization levels; 200, 250 kg $ha^{-1}$) plots compared to the control (nitrogen fertilization level; 100 kg $ha^{-1}$) plot. Nitrogen use efficiency was showed significantly high in the NPK+rice straw compost (nitrogen fertilization levels; 100, 150 kg $ha^{-1}$) plot compared to the control (nitrogen fertilization level; 100 kg $ha^{-1}$) plot. Therefore, it was suggested that application of organic inputs is helpful in improving soil fertility and physical conditions and thus in N uptake.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.5
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• pp.364-370
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• 2009

This study was conducted to survey, analyze on the compaction layer and the plow layer at Jeonbug and Jisan series paddy soil, which is the representative soil in fluvio-marine and local alluvium, respectively. The depths of surface soil were 12.6 and 12.7 cm in Jeonbug and Jisan series, respectively. A plowing depth was 10.5 cm. The properties of compaction layer in two soil series were as follows. The hardness were $14.7kg\;cm^{-2}(25.3mm)$ and $8.7kg\;cm^{-2}(22.1mm)$ in Jeonbug and Jisan series, respectively. The thickness were 22.3 cm and 17.8 cm in Jeonbug and Jisan series, respectively. The depth of soil compaction, which means depth from surface, were 15 and 20 cm in Jeonbug and Jisan series, respectively. The relationship between the hardness of compaction layer and the depth of surface soil showed negative correlation, however relationship between the hardness and the thickness of compaction layer showed positive correlation. Soil temperature was lower in compaction layer than in plow layer. This temperature differences between compaction layer and plow layer were from 1.0 to $2.5^{\circ}C$ in Jeonbug series and from 0.7 to 2.1 in Jisan series. The soil physical properties of compaction layer were higher in bulk density and solid phase and lower in porosity and gaseous phase than those of plow layer in all soil series. The soil chemical properties of compaction layer were higher in pH, content of available silicate, exchangeable calcium and magnesium but lower in total nitrogen, content of organic matter and available phosphate than those of plow layer in all soil series. Cation exchangeable capacity and content of exchangeable potassium were similar between compaction layer and plow layer in Jeonbug series, however, in Jisan series these were lower in compaction layer than in plow layer. Elution amount of inorganic nitrogen were lower in compaction layer than in plow layer in all soil series. The content of soluble Fe and Mn were plenty in compaction layer compared with plow layer and these tendency was apparent in Jeonbug series. The water depth decrease were fast until the latter part of June, and were slow as $1{\sim}3mm\;day^{-1}$ for July and August, and were fast again from september. Rice roots distributions as each soil series and tillage method were 25 cm at rotary plowing in Jeonbug series, 30 cm at deep plowing in Jeonbug series, and 20 cm at tillage in Jisan series. Dry weight per m2 at heading stage were much in order of deep plowing in Jeonbug series, rotary plowing in Jeonbug series, and tillage in Jisan series.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.5
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• pp.371-378
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• 2009

This study was carried out to investigate the improvement effect of soil fertility by incorporation of GMC(green manure crops) at rice cropping after cultivation GMC such as the barley for alternative rye in paddy field over the past two years(2006~2007). Plots, which consisted of incorporation time of GMC as rye; heading stage, barley; heading stage, heading stage of rye and 10days after heading stage were divided by amount of applied rates; standard fertilizer fertilization, diagnosis fertilization and non-fertilization. we investigated change of soil physico-chemical properties, degree of decomposition on GMC in soil, growth and yield potential. The obtained results were summarized as follows. The fresh weight of GMC at incorporation time on heading stage of rye, heading stage and 10days after heading stage of barley were $2,715,\;2,352,\;2,867kg\;10a^{-1}$ respectively. Content of total nitrogen at three incorporation times was 1.31, 1.46, 1.38% and the C/N ratio were 33.4, 28.7, and 34.6, respectively. Some soil physical properties, such as soil hardness and bulk density tended to decrease with incorporation of GMC, while surface soil depth and porosity were increased. Some soil chemical properties, such as content of exchangeable cations and cation exchangeable capasity(CEC) were increased with incorporation of GMC compared with before experiment. Rice yields was increased 3~9% in diagnosis application plots on application of barley compared with control($559kg\;10a^{-1}$) and incorporation of barley caused to improve perfect kernel ratio 73.6~78.7% in appearance characteristics of brown rice compared with cotrol(73.0%). It was found that incorporation with 10days after heading stage of barley was more effective to reduce chemical nitrogen fertilizer and to improve soil fertility.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.6
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• pp.454-459
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• 2007

This experiment was conducted to investigate the effect of long-term continuous application of fertilizers for rice cultivation from 1954 to 2003. Changes of physical and chemical properties of paddy soil and the rice yield by continuous application of fertilizers, particularly rice straw compost, over fifty years were discussed in this paper. The rice yields of compost applied plots were 5~12% higher while those of no fertilizer plots were 21~38% lower compared to those of NPK fertilizers applied plots. Uptakes of T-N, $P_2O_5$, $K_2O$, CaO, MgO, and $SiO_2$ by rice plants were significantly increased by the application of straw compost. Bulk density, hardness, and liquid phase of soil in compost applied plots were significantly decreased while gaseous phase and cation exchange capacity (CEC) of soil were increased compare to those in NPK plots. When the bulk density of soil was increased the rice yield was decreased. The soil organic matter (SOM) content tended to increase in compost applied plots whereas no significant differences were found in other treatments. The soil organic matter content increased by $0.4g\;kg^{-1}\;yr^{-1}$ when $7.5Mg\;ha^{-1}\;yr^{-1}$ of rice straw compost applied in paddy land. The compost application rate recommendation for rice cultivation in Korea could be revised by the results of this study.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.2
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• pp.136-144
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• 2007

The objectives of this study were to compare nutrient input by throughfall, stemflow and litterfall and concentration of nutrient in soil water between deciduous forest stand and Larix kaempferi plantation at Mt. Joongwang, Pyongchang-gun, Gangwon-do. The amount of rainfall interception during study period in deciduous forest stand and L. kaempferi plantation was 12% and 36%, respectively. Concentrations of cation ($Na^+$, $Mg^{2+}$, $K^+$ and $Ca^{2+}$) in throughfall were not different, while concentration of $Cl^-$ in stemflow was higher in L. kaempferi plantation. The results indicated that annual nutrient inputs by rainfall with the exception of $Cl^-$ were significantly greater in deciduous forest stand. In soil water, concentrations of anion ($Cl^-$, $NO_3{^-}$ and $SO{_4}^{2-}$) in A-layer, and $Ca^{2+}$ and $Cl^-$ in B-layer were higher in L. kaempferi plantation. Litterfall input during study period was $2,589kg\;ha^{-1}$ in deciduous forest stand and $1,046kg\;ha^{-1}$ in L. kaempferi plantation. Concentration of N was higher in L. kaempferi plantation, while N input from litterfall was greater in the deciduous forest stand ($36.81kg\;ha^{-1}yr^{-1}$) than L. kaempferi plantation ($16.16kg\;ha^{-1}yr^{-1}$). $Na^+$, $Mg^{2+}$, $K^+$ and $Ca^{2+}$ in litterfall collected from deciduous forest stand were found to be higher than those from the L. kaempferi plantation. Also, input of those were greater in deciduous forest stand. Thus, total nutrient input by throughfall, stemflow and litterfall was greater in deciduous forest stand than L. kaempferi plantation, significantly.

• Journal of the Korea Organic Resources Recycling Association
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• v.19 no.1
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• pp.123-130
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• 2011

Objectives of this study were to compare the environmental effects of digestates produced in bioenergy village on the rice paddy field for recycling. Digestates were applied to the soils and the soil properties and the crop responses were analyzed according to the standard methods of soil evaluation. Plant height and the number of tiller showed similar results in both the conventional and digestate treated field, and the yield of rough rice was higher in the field treated with digestates than that with chemical fertilizer. The amounts of nitrogen absorbed in straw and grain were larger in the digestates-treated field than chemical fertilizer-treated one, and efficiency of nitrogen applied was shown to be the highest in 100% treated digestate of the pig manure. Exchangeable cation and pH increased in the soil treated with digestate after harvesting, but salt was not accumulated. With these results, it was concluded that resource recycling in green town can be facilitated through the securement of arable lands for the application of digestates and the proper use of these fertilizers. Long-term effects of digestate application on the soil environment should be sustainingly studied.

• Korean Chemical Engineering Research
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• v.57 no.6
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• pp.868-873
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• 2019

In this study, the evaluation of performance of AORFB using methyl viologen and TEMPOL as organic active materials in neutral supporting electrolyte (NaCl) with various membrane types was performed. Using methyl viologen and TEMPOL as active materials in neutral electrolyte solution, the cell voltage is 1.37V which is relatively high value for AORFB. Two types of membranes were examined for performance comparison. First, when using Nafion 117 membrane which is commercial cation exchange membrane, only the charge process occurred in the first cycle and the single cell couldn't work because of its high resistance. However, when using Fumasep anion exchange membrane (FAA-3-50) instead of Nafion 117 membrane, the result was obtained as the totally different charge-discharge graphs. When current density was $40mA{\cdot}cm^{-2}$ and cut off voltage range was from 0.55 V to 1.7 V, the charge efficiency (CE) was 97% and voltage efficiency (VE) was 78%. In addition, the discharge capacity was $1.44Ah{\cdot}L^{-1}$ which was 54% of theoretical capacity ($2.68Ah{\cdot}L^{-1}$) at $10^{th}$ cycle and the capacity loss rate was $0.0015Ah{\cdot}L^{-1}$ per cycle during 50 cycles. Through cyclic voltammetry test, it seems that this difference in the performance between the full cell using Nafion 117 membrane and Fumasep anion exchange membrane came from increasing resistance due to chemical reaction between membrane and active material, not the capacity loss due to cross-over of active material through membrane.