• Korean Journal of Soil Science and Fertilizer
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• v.46 no.6
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• pp.641-646
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• 2013

Chemical properties of agricultural soils in Korea have been investigated at four-year interval in order of paddy, polytunnel, upland, and orchard soils since 1999; polytunnel soils were investigated over the whole country in 2000, 2004, 2008, and 2012. Polytunnel soils were taken from the surface (0-15 cm) and subsurface (15-30 cm) at 2,651, 1,274, 1,374 and 1,374 sites in all provinces of South Korea. One hundred sampling sites located in more than 400 m altitude were additionally investigated in 2008 and 2012. Average of soil chemical properties in 2012 except Jeju province were 6.6 for pH, 3.2 dS $m^{-1}$ for EC, 37 g $kg^{-1}$ for organic matter (OM), 1,049 mg $kg^{-1}$ for available (Avail.) phosphate, 1.58 $cmol_c\;kg^{-1}$ for exchangeable (Exch.) K, 10.6 $cmol_c\;kg^{-1}$ for Exch. Ca, and 3.3 $cmol_c\;kg^{-1}$ for Exch. Mg. Except pH, averages of all chemical properties exceeded the upper limit of optimal range. The median values except pH showed a lower value than the averages. The pH, OM and Exch. Ca had slightly increased from 6.3 to 6.6, from 34 to 37 g $kg^{-1}$, and from 7.7 in 2000 to 10.6 $cmol_c\;kg^{-1}$ in 2012, respectively. The order of sample ratios exceeding the optimal range were Avail. $P_2O_5$ (83%) > Exch. Ca (80%) > Exch. K (70%) > Exch. Mg (65%) > EC (55%) > OM (48%) > pH (29%) in 2012. The order of sample ratios below the optimal range was OM (25%) > Exch. K (25%) > pH (20%), Exch. Mg and Avail. $P_2O_5$ (9%) > Exch. Ca (6%) in 2012. The excessive proportion of pH, Exch. Ca, Exch. Mg and OM slightly increased, while the insufficient proportion of those decreased. Approximately 55% of polytunnel soils exceeding EC 2 dS $m^{-1}$ was evaluated with salt accumulated soils having the risk of growth disorder of crops. Nutrient contents in polytunnel soils in Korea showed high level especially Avail. $P_2O_5$ and Exch. cations. Therefore, recommended fertilization based on soil testing or plant testing is needed for soil nutrient management.

• Journal of Korean Society of Forest Science
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• v.109 no.2
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• pp.157-168
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• 2020

The sensitivity of forest soil to acidification in the Republic of Korea (ROK) was evaluated based on pH_H2O, cation exchange capacity (CEC), and base saturation (BS). Sensitivity to acidification was categorized into three grades: adequate level (AL, pH ≧ 4.2, CEC ≧ 15cmol/kg, BS ≧ 15%), caution level (CL, at least one indicator is below AL), and severe Level (SL, all three indicators are below AL). Soil samples were collected from the 65 stationary monitoring plots (40 × 40 ㎢), distributed throughout ROK. Only 19% of soil samples were classified as AL, while 66% and 15% were CL and SL, respectively. The median of pH_H2O, CEC, BS, and Ca/Al indicator in AL soils was pH 4.64, 20.7cmol/kg, 29%, and 6.3, respectively. Moreover, BC_ex (K⁺, Mg²⁺, Ca²⁺) and available phosphorus (AP) concentration compared with a threshold value and molar ratio of BC_ex and AP to total nitrogen (TN) was high. This indicates that AL soils have a good nutrient condition. The molar Ca/Al ratio, an indicator for toxicity of exchangeable aluminum (Al_ex), was more than 1, indicating no negative impact of Al_ex on plant growth. On the contrary, the median of pH_H2O, CEC, and BS in SL soils was pH 4.02, 13.2cmol/kg, and 10%, respectively. The Ca/Al index was less than 0.6, which indicates that negative impacts of Al_ex on plants were high. Furthermore, both the concentration of BC_ex in SL soils and the BC_ex/TN ratio were the lowest among the three acidity degrees. This shows that SLsoils can be degraded by soil acidification compared with less acidic soils.

• Korean Journal of Environmental Agriculture
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• v.18 no.4
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• pp.372-377
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• 1999

Objective of this research was to draw the basic criteria of the compost maturity evaluation, by assessing the stability of chemical and physical properties of the bark and piggery manure byproduct composts during the composting. Colors of the mature composts were black and dark brown for the bark and piggery manure by-product composts, respectively. Good earthy odor was detected for both by-product composts after approximately 40 days composting, by which odors of the original raw materials were disappeared. pH and EC of the mature bark: compost were stabilized at 6.5 and 1dS/m, respectively. The respective values for the piggery compost were stabilized at 7.2 and 6dS/m. Organic matter contents were decreased with time to be stabilized at about 60% at the end of composting. During composting, total N contents of the bark and piggery composts were maintained at $1.1{\sim}1.5%$, and $1.5{\sim}2.2%$, respectively. For both fertilizers, $NH_4-N$ contents were increased at the initial stage bur. decreased after the middle stages of decomposition, resulting in the increase of $NO_3-N$ contents. Total inorganic N contents were increased with time. C/N ratios of both mature composts were stabilized at $25{\sim}27$. CEC of the bark compost was increased logarithmically with time and that of mature compost was 87cmol(+)/㎏. CEC of the piggery manure compost was hyperbolic function with rime and reached at 70cmol(+)/㎏ at the mature stage. Crude fiber analysis indicated that relative contents of lignin were increased with composting by compensating for the decreases of cellulose and hemicellulose contents.

• Journal of the Mineralogical Society of Korea
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• v.21 no.3
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• pp.313-320
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• 2008

Hectorite was synthesized under hydrothermal conditions and its physicochemical properties have been investigated in terms of temperature, pH, and organic agent to observe the change of doll basal spacing. The IR, CEC, MB, swelling volume and specific surface area of the hectorite were measured for the characterization. The solid/liquid ratio of hectorite to distilled water before mixing with other materials was also determined for its use as a multi-functional material. The $d_{001}$ basal spacing decreased from $12.63\;\AA$ at room temperature to $10.19\;\AA$ at $650^{\circ}C$ in the heating tests. As the pH of hectorite slurry increased. the $d_{001}$ basal spacing decreased. reaching the lowest value of $13.33\;\AA$ at pH 7 and afterward, increased. All the fool basal spacings of the hectorite increased when it was intercalated with the following solvents: $12.86\;\AA$ in diethyl ether, $13.31\;\AA$ in acetonitrile. $13.59\;\AA$ in methanol, $14.05\;\AA$ in ethanol, $15.69\;\AA$ in acetone, and $17.42\;\AA$ in ethylene glycol. Our IR analysis results were in good agreement with those of other researchers. The CEC, MB, swelling volume and specific surface area of hectorite were determined to be 105 cmol/kg, 80 cmol/kg, $68\sim74ml/2g$ and $213m^{2}/g$, respectively. Also, the hectorite to distilled water ratio of 2 to 100 was found to be most favorable for mixing with other materials such as the solvents mentioned above.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.4
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• pp.342-346
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• 1996

Field experiments were conducted to investigate the mode of changes in exchangeable K contents in the soil under the continued(for three years) application of different levels of K fertilizer(KCl) with and without application of conventional compost(CC) and chicken-dung derived compost (CDC) for red pepper cultivation at two field parcels with different exchageable K contents on Gopyong silty loamy soil. The application of KCl at standard rate for red-pepper resulted in the increase in exchangeable K in the soil after each harvest of the crop. while no application of K and the application of KCl at one half of the standard rate tended to lower the exchangeable K in top soil with the cultivation of the crop. The application of compost in addition to KCl ammplified the difference in exchangeable K in the soil before and after the harvest of each crop. An equation could resonably well predict the exchageable K content in top soil after the years of crop cultivation, under different treatments. were developed.

• The Korean Journal of Pesticide Science
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• v.8 no.4
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• pp.299-308
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• 2004

In order to elucidate the behavior of bensulfuron-methyl, a sulfonylurea herbicide, in a soil/plant microecosystem, rice plants (Oryza sativa L.) were grown for 12 weeks in the specially made stainless steel pots (17cm I.D. $\times$ 10cm H.) containing two different paddy soils treated with fresh and 13-week-aged residues of [phenyl-$^{14}C$]bensulfuron-methyl, respectively. During the aging period, the mineralization to $^{14}CO_2$ from soil A (OM, 3.59%; CEC, 7.65 $cmol^+\;kg^{-1}$; texture, sandy clay loam) and B (OM, 1.62%; CEC, 4.51 $cmol^+\;kg^{-1}$; texture, sandy loam) amounted to 6.79 and 10.15% of the originally applied $[^{14}C]$bensulfuron-methyl, respectively. The amounts of $^{14}CO_2$ evolved from the soils with fresh residues were higher than those from the soils with aged residues. At harvest after 12-week growing, $^{14}C$-radioactivity absorbed and translocated into rice plants from soils A and B containing fresh residues of bensulfuron-methyl was 1.53 and 4.40%, while 4.04 and 6.37% in the two soils containing aged residues, respectively. Irrespective of aging and soil type, the $^{14}C$-radioactivity remaining in soil ranged from 80.41 to 98.87% of the originally applied $[^{14}C]$bensulfuron-methyl. The solvent extractability of tile soils was $39.25\sim70.39%$, showing the big differences among the treatments. Most of the nonextractable soil-bound residues of $[^{14}C]$bensulfuron-methyl were incorporated into the fulvic acid fraction$(61.32\sim76.45%)$. Comparing the microbial activity of the soils with rice plants grown with that of the soils without them, the former was $1.6\sim3.0$ times higher than the latter. However, it did not correlate with the $^{14}CO_2$ evolution.

• Journal of Life Science
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• v.24 no.4
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• pp.403-410
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• 2014

This study was conducted in organic certification soil for the comparison of heavy metals, nutrients, and irrigated water standards to certify a farm. It was carried out in 811 paddy fields of organic rice (Oryza sativa L.) cultivated at Goseong-Gun. The amounts of 8 heavy metals, Cd, Cu, As, Hg, Pb, $Cr^{6+}$, Zn, and Ni were found to be 0.05, 14.5, 1.08, 0.92, 10.7, 1.34, 35.9, and 22.2 mg $kg^{-1}$ in regular sequence in the organic paddy soil, and they were 0.32, 13.6, 1.01, 0.03, 10.4, 0.91, 42.4 and 22.5 mg $kg^{-1}$ in the non-pesticide paddy soil. In comparing organic and non-pesticide paddy soil with respect to the chemical characteristics of the soil, the average pH and the amount of organic matter, available phosphate and available silicate were 5.88 and 27.6 g $kg^{-1}$, 134.5 mg $kg^{-1}$, and 165.3 mg $kg^{-1}$, while they were 5.78 and 32.1 g $kg^{-1}$, 107.7 mg $kg^{-1}$, and 175.2 mg $kg^{-1}$, respectively. The amount of exchangeable cation $K^+$, $Ca^{2+}$, and $Mn^{2+}$ were 0.25, 5.20, and 1.04 cmol+ $kg^{-1}$ in organic paddy soil, while they were 0.38, 5.13, and 1.19 cmol+ $kg^{-1}$ in non-pesticide paddy soil. The pH, DO, BOD, COD and SS conditions of the irrigated water used in the organic paddy soil were found to be 7.23, 8.40, 2.80, 1.86, and 2.58 mg $l^{-1}$ and the condition of irrigated water used in the non-pesticide paddy soil were found to be 7.65, 9.16, 2.25, 4.11, and 4.00 mg $l^{-1}$, respectively. Based on these findings, we suggest that environmentally-friendly certificates in Korea have to unify organic and non-pesticide agro-products in an organic standard in food policy and control because there is no difference between soil and irrigated water standards in the two certifications.

• Korean Journal of Environmental Agriculture
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• v.24 no.3
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• pp.253-260
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• 2005

Salt accumulation in the plastic film house soils under continuous cultivation condition causes problems such as salt damages to plants, nitrate accumulation in vegetables, groundwater contamination, etc. due to excess application of fertilizers. Objective of this research was to find an optimum adsorbent to reduce salt concentration in the soil solution of plastic film house soils, where crop injuries have been observed due to the salt accumulation. The soils were significantly high in available P $(1,431{\sim}6,516mg\;kg^{-1}),\;NO_3-N\;(117.60{\sim}395.73mg\;kg^{-1})$, exchangeable Ca $(4.06{\sim}11.07\;cmol_c\;kg^{-1})$ and Mg $(2.59{\sim}18.76\;cmol_c\;kg^{-1})$, as compared to those of the average upland soils in Korea. Soils were treated with each of adsorbent such as ion-exchange resin, zeolite, rice bran, etc. at 2% level and prepared into saturated-paste samples. After equilibrium, soil solution was vacuum-extracted from the soil and measured for changes of the pH, EC, and concentrations of $Ca^{2+},\;Mg^{2+},\;K^+,\;Na^+,\;{NH_4}^+,\;{PO_4}^{3-}\;and\;{NO_3}^-$. Rice bran effectively removed ${PO_4}^{3-}\;and\;{NO_3}^-$ in the soil solution up to 100%. Efficiency was decreased in the orders of rice bran > ion-exchange resin > zeolite. Removal efficiencies of zeolite and ion-exchange resin for $Ca^{2+}$ were ranged from 1 to 65% and from 7 to 61%, respectively. Ion-exchange resin was also effective for removing $Mg^{2+},\;K^+,\;Na^+,\;and\;{NH_4}^+$. Overall results demonstrated that rice bran and ion-exchange resin could be applicable for salt accumulated soil to remove the respective anion and cation.

• Journal of Bio-Environment Control
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• v.21 no.4
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• pp.336-342
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• 2012

Inorganic materials were commonly used as container media in domestic plant factories. Objective of this research was to secure the information in soil physical and chemical properties of inorganic materials such as vermiculites and perlites. To achieve this, 12 gold and silver vermiculites from China, Zimbabwe, and South Africa and 5 perlites from China were collected based on the marketing grades (MG) in particle sizes and analyzed for determination of their characteristics. The percentage of particles larger than $710{\mu}m$, in China perlite MG 3~5 mm, China silver vermiculites MG > 8 mm and MG 3~8 mm were 99.9%, 99.8%, and 99.7%, respectively, which were much higher than 28.4% in China gold vermiculite MG 0.3~1.0 mm, 14.0% in perlite MG < 1.0 mm, and 12.6% of Zimbabwe silver vermiculite MG < 1.0 mm. The container capacities of perlite MG < 1.0 mm and South Africa silver vermiculite MG 0.25~1.0 mm were 72.0% and 71.1%, respectively. The air space in China silver vermiculite MG 3~8 mm was 49.3% which was higher than other materials tested. However, the China gold and silver vermiculites MG 0.3~1 mm had 3.5% and 2.4% in air space indicating that possible problems could occur in soil aeration when they are used for container media. The percentage of easily available and buffering water of China gold vermiculite MG 0.3~1 mm and perlite MG < 1.0 mm were the highest among test materials. The ranges of pH and electrical conductivity were 6.36 to 10.7 and 0.032 to $0.393dS{\cdot}m^{-1}$ in vermiculites and 7.78 to 8.62 and 0.030 to $0.041dS{\cdot}m^{-1}$ in perlite, respectively. The cation exchange capacity of China silver vermiculite MG 0.3~1 mm were $14.7cmol{\cdot}kg^{-1}$ that was 10 times as high as $0.34cmol{\cdot}kg^{-1}$ in perlite MG 1~2.5 mm. The vermiculites had the higher contents of exchangeable cations such as Ca, K, and Na, than those of perlites.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2004.05a
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• pp.255-257
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• 2004

오염 토양 개선사업이 완료된 밀양시 구운동 광산의 이.화학적 성분을 기초로 하여 비경작지의 일부 야생식물 중 축적된 중금속 함량을 분석한 결과, 토양의 각 지점별 평균 함량은 유기물 13.18g/kg, 유효인산 40.65mg/kg, 석회 5.06, 칼슘 6.85, 고토 1.94cmol/kg으로서 우리나라 밭 토양의 평균보다 낮았고 중금속 함량은 아연(Zn)이 평균 383.1mg/kg, 구리(Cu) 135.2mg/kg, 납(Pb) 105.4mg/kg로 조사되었다. 조사 지점 중 광미의 퇴적으로 인한 오염이 있는 광산 위 st. 3에서 아연(945mg/kg)과 구리(535mg/kg)의 함량이 가장 높았고 다음이 광미가 많이 잔재하고 있는 광구 앞인 st. 4였으며 이곳은 납(289.5mg/kg)의 함량이 가장 높은 지점이었다. 식물체 내의 중금속 함량은 차즈기>쑥>억새>싸리 순이었고 특히 차즈기의 경우는 다량의 중금속이 축적되어 있어 중금속 오염 지역에 대한 내성이 있는 지표종으로 추측되어 이에 대한 중금속 축적 능력 확인 실험이 필요할 것으로 판단된다.