• Korean Journal of Soil Science and Fertilizer
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• v.5 no.2
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• pp.1-38
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• 1972

This study, designed to establish a classification system of paddy soils and suitability groups on productivity and management of paddy land based on soil characteristics, has been made for the paddy soils on the Gimje-Mangyeong plains. The morphological, physical and chemical properties of the 15 paddy soil series found on these plains are briefly as follows: Ten soil series (Baeggu, Bongnam, Buyong, Gimje, Gongdeog, Honam, Jeonbug, Jisan, Mangyeong and Suam) have a B horizon (cambic B), two soil series (Geugrag and Hwadong) have a Bt horizon (argillic B), and three soil series (Gwanghwal, Hwagye and Sindab) have no B or Bt horizons. Uniquely, both the Bongnam and Gongdeog series contain a muck layer in the lower part of subsoil. Four soil series (Baeggu, Gongdeog, Gwanghwal and Sindab) generally are bluish gray and dark gray, and eight soil series (Bongnam, Buyong, Gimje, Honam, Jeonbug, Jisan, Mangyeong and Suam) are either gray or grayish brown. Three soil series (Geugrag, Hwadong and Hwagye), however, are partially gleyed in the surface and subsurface, but have a yellowish brown to brown subsoil or substrata. Seven soil series (Bongnam, Buyong, Geugrag, Gimje, Gongdeog, Honam and Hwadong) are of fine clayey texture, three soil series (Baeggu, Jeonbug and Jisan) belong to fine loamy and fine silty, three soil series (Gwanghwal, Mangyeong and Suam) to coarse loamy and coarse silty, and two soil series (Hwagye and Sindab) to sandy and sandy skeletal texture classes. The carbon content of the surface soil ranges from 0.29 to 2.18 percent, mostly 1.0 to 2.0 percent. The total nitrogen content of the surface soil ranges from 0.03 to 0.25 percent, showing a tendency to decrease irregularly with depth. The C/N ratio in the surface soil ranges from 4.6 to 15.5, dominantly from 8 to 10. The C/N ratio in the subsoil and substrata, however, has a wide range from 3.0 to 20.25. The soil reaction ranges from 4.5 to 8.0. All soil series except the Gwanghwal and Mangyeong series belong to the acid reaction class. The cation exchange cpacity in the surface soil ranges from 5 to 13 milliequivalents per 100 grams of soil, and in all the subsoil and substrata except those of a sandy texture, from 10 to 20 milliequivalents per 100 grams of soil. The base saturation of the soil series except Baeggu and Gongdeog is more than 60 percent. The active iron content of the surface soil ranges from 0.45 to 1.81 ppm, easily-reduceable manganese from 15 to 148 ppm, and available silica from 36 to 366 ppm. The iron and manganese are generally accumulated in a similar position (10 to 70cm. depth), and silica occurs in the same horizon with that of iron and manganese, or in the deeper horizons in the soil profile. The properties of each soil series extending from the sea shore towards the continental plains change with distance and they are related with distance (x) as follows: y(surface soil, clay content) = $$-0.2491x^2+6.0388x-1.1251$$ y(subsoil or subsurface soil, clay content) = $$-0.31646x^2+7.84818x-2.50008$$ y(surface soil, organic carbon content) = $$-0.0089x^2+0.2192x+0.1366$$ y(subsoil or subsurface soil, pH) = $$-0.0178x^2-0.04534x+8.3531$$ Soil profile development, soil color, depositional and organic layers, soil texture and soil reaction etc. are thought to be the major items that should be considered in a paddy soil classification. It was found that most of the soils belonging to the moderately well, somewhat poorly and poorly drained fine and medium textured soils and moderately deep fine textured soils over coarse materials, produce higher paddy yields in excess of 3,750 kg/ha. and most of the soils belonging to the coarse textured soils, well drained fine textured soils, moderately deep medium textured soils over coarse materials and saline soils, produce yields less than 3,750kg/ha. Soil texture of the profile, available soil depth, salinity and gleying of the surface and subsurface soils etc. seem to be the major factors determining rice yields, and these factors are considered when establishing suitability groups for paddy land. The great group, group, subgroup, family and series are proposed for the classification categories of paddy soils. The soil series is the basic category of the classification. The argillic horizon (Bt horizon) and cambic horizon (B horizon) are proposed as two diagnostic horizons of great group level for the determination of the morphological properties of soils in the classification. The specific soil characteristics considered in the group and subgroup levels are soil color of the profile (bluish gray, gray or yellowish brown), salinity (salic), depositonal (fluvic) and muck layers (mucky), and gleying of surface and subsurface soils (gleyic). The family levels are classified on the basis of soil reaction, soil texture and gravel content of the profile. The definitions are given on each classification category, diagnostic horizons and specific soil characteristics respectively. The soils on these plains are classified in eight subgroups and examined under the existing classification system. Further, the suitability group, can be divided into two major categories, suitability class and subclass. The soils within a suitability class are similar in potential productivity and limitation on use and management. Class 1 through 4 are distinguished from each other by combination of soil characteristics. Subclasses are divided from classes that have the same kind of dominant limitations such as slope(e), wettness(w), sandy(s), gravels(g), salinity(t) and non-gleying of the surface and subsurface soils(n). The above suitability classes and subclasses are examined, and the definitions are given. Seven subclasses are found on these plains for paddy soils. The classification and suitability group of 15 paddy soil series on the Gimje-Mangyeong plains may now be tabulated as follows.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.2
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• pp.112-117
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• 2008

A pot experiment was conducted to study the effect of application rate of anaerobically digested pig slurry on the growth of Chinese cabbage and the outflow characteristics of N and P from leaching and runoff in the upland. Anaerobically digested pig slurry(ADPS) was applied rates of 0, 6, 12, and $18L\;pot^{-1}$, and Chinese cabbages were grown for 50 days. Dry matter yield of Chinese cabbage increased significantly at the rates of 6 and $12L\;pot^{-1}$, but decreased at the rate of $18L\;pot^{-1}$ due probably to the high salinity. The EC(1:5) of the soil receiving $18L\;pot^{-1}$ of anaerobically digested pig slurry was $0.28dS\;m^{-1}$, which was significantly higher than those receiving 6 and $12L\;pot^{-1}$ of anaerobically digested pig slurry. For the leachate and runoff, N and P concentration increased with the application rate of ADPS. Therefore, considering the dual goal of optimum crop growth and minimal discharge of non-point pollution sources to water system, this study suggests that a testing of a site-specific proper application rate of liquid pig slurry including ADPS is prerequisite to achieving optimum agricultural productivity while minimizing water quality degradatio.

• Journal of Plant Biotechnology
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• v.30 no.4
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• pp.323-328
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• 2003

Soil salinity is one of the most serious abiotic stresses limiting the productivity of agricultural crops. To cope with salt stress, plants respond with physiological, developmental and biochemical changes, including the synthesis of a number of proteins and the induction of gene expression. Salicornia herbacea is a halophytic plant that grows in salt marshes and on muddy seashores. In order to understand the biochemical and molecular mechanisms of salt tolerance in S. herbacea, we isolated several genes that involved in the salt tolerance by mRNA differential display. Here we report the cloning of a cDNA encoding fructose-1, 6-bisphosphate aldolase, named ShADL, which is 1293 bp long and contains an open reading frame consisted of 359 amino acids with calculated molecular mass of 39 kDa. ShADL protein showed 86％ identity with Arabidopsis and 78％ with aldolase of common ice plant. Northern blot analysis revealed that the transcript of ShADL gene was increased dramatically depending on the NaCl concentrations.

• Journal of the Mineralogical Society of Korea
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• v.25 no.3
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• pp.155-162
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• 2012

We observed characteristic oxidation and dissolution phenomena induced by dissolved oxygen for mackinawite that is produced via sulfate-reducing bacteria (SRB) living in anaerobic environments such as soils and groundwater. We tried to recognize the role of the sulfide minerals that usually coexist with some stabilized radionuclides (e.g., reduced uranium), which can be reoxidized and redissolved by an oxygen-rich groundwater invaded into a contaminated area. The mackinawite produced by 'Desulfovibrio desulfuricans', a sulfate-reducing bacterium, was conducted to be dissolved for 2 weeks by some oxidants such as 'hydrogen peroxide' and 'sodium nitrite'. Although mineralogical oxidation and dissolution characteristics were different from each other according to the oxidants, the initially oxidized solution was early stabilized through the oxygen consumption by ${\mu}m$-sized sulfide particles and the resultant increase of sulfate in solution. From these results, we can anticipate that the large amount of sulfide minerals generated by SRB can not only repress the anoxic environment to be disturbed by the consumption of oxygen in groundwater, but also contribute to stabilize the reduced/precipitated radionuclides as a buffer material for a long time.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.1
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• pp.67-73
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• 2014

In this study, the residual heavy metals in the mine tailings, primarily treated by soil washing, were stabilized using phosphate salts. The concentrations of residual contaminants in the washed mine tailings were As (1,861 mg/kg), Cd (20 mg/kg), Cu (56 mg/kg), Pb (2,149 mg/kg), and Zn (633 mg/kg). They were stabilized with $CaHPO_4$, $Ca(H_2PO_4)_2{\cdot}H_2O$, and hydroxyapatite at 0.1 wt%, 1 wt%, and 10 wt% for 1, 3, 5, 7, and 14 days. It was found that 1 wt% $Ca(H_2PO_4)_2{\cdot}H_2O$ was optimum in our experiments, but the stabilization duration did not affect the efficiency. After stabilization with 1 wt% $Ca(H_2PO_4)_2{\cdot}H_2O$ for 1 day, the concentrations of arsenic and heavy metals, As (0.328 mg/L), Cd (0.250 mg/L), Cu (0.143 mg/L), Pb (0.359 mg/L), and Zn (2.622 mg/L), in TCLP leachate were below the RCRA-TCLP limits, which meant the contaminants in the treated mine tailings were stably immobilized.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.734-744
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• 2011

A soil stabilization method is an effective and practical remediation alternative for arsenic (As) and heavy metal contaminated farmland soils nearby abandoned metal mine in Korea. This method is a technique whereby amendments are incorporated and mixed with a contaminated soil. Toxic metal bind to the amendments, which reduce their mobility in soil, so the successful stabilization of multi-element contaminated soil depends on the combination of critical elements in the soil and the type of amendments. The objective of this study is to investigate the treatment effects and applicability of limestone (LS) and steel refining slag (SRS) as the amendment for farmland soil contaminated with As and heavy metals, and a lab-column test was conducted for achieving this purpose. The result showed that soil treated with LS and SRS maintained pH buffer capacity and, as a result, the heavy metal leaching concentration was quite low below the water quality standard compared to untreated soil which leachate exceeding the water quality standard was observed, however, the arsenic concentration rather increased with increasing mixture ratio of SRS. This was believed to be related to phosphorus (P) contained in SRS, and dominancy in the competitive adsorption relation between As and P binding strongly to iron might be different according to soil characteristic. We suggested that LS is a effective amendment for reducing heavy metals in soil, and SRS should be used after investigating its applicability based on the adsorption selectivity of arsenic and phosphorus in selected soil.

• Journal of Applied Biological Chemistry
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• v.60 no.2
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• pp.125-131
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• 2017

Nine strains of high concentrations of salt-tolerant bacteria were isolated from the rhizosphere and rhizoplane of the halophyte plant Suaeda japonica grown in Gochang Buan tidal flat. The isolated bacteria were classified as genera Vibrio (strains JRS-1, -2, -3, -4, and -5, and JRL-1 and -4) and Bacillus (strains JRL-2 and -3) based on the 16S rRNA gene sequence similarity. The optical growth condition for salt concentration was examined on the selected, representative strains. Strain JRS-1 with the closest relative of Vibrio neocaledonicus showed the highest growth rate at the total salt concentration of 6% among the incubation conditions of 3-8% salt concentrations. Strain JRL-2 with the closest relative of Bacillus thuringiensis showed the tendency that growth rate increased with increasing salt concentrations and the maximum growth rate at 7% of the total salt concentration. The isolated bacteria showed salt-resistances to higher salt concentrations than their habitat soils with 3%. In addition, we identified evidences of potentially plant interaction-relevant enzymatic activities, from utilization of some substrates rich in plants, such as triglyceride, ${\rho}$-nitrophenyl-${\alpha}$,$\text\tiny{D}$-glucoside, and ${\rho}$-nitrophenyl-${\beta}$,$\text\tiny{D}$-glucoside.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.9 no.2
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• pp.63-71
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• 2011

A large volume of uranium electrokinetic leachate has been generated during the electrokinetic decontamination to remove uranium from contaminated soil. The treatment technology for the reuse of the uranium leachate was developed. The concentration of uranium in the generated uranium leachate was 180 ppm and concentrations of Mg(II), K(I), Fe(II), and Al(III) ions ranged from 20 ppm to 1,210 ppm. The treatment process for uranium leachate consisted mainly of mixing and cohesion, precipitation, concentration, and filtration. In order to obtain the pH=11 of a precipitate solution, the calcium hydroxide needs to be 3.0g/100ml and the sodium hydroxide needed to be 2.7g/100ml. The results of several precipitation experiments showed that a mixture of NaOH+0.2g alum+0.15g magnetite was an optimal precipitant for filtration. The average particle size of precipitate with NaOH+alum+0.15g magnetite was $600\;{\mu}m$. Because the total value of metal concentrations in supernatant at pH=9 was the smallest, sodium hydroxide should be added with 0.2g alum and 0.15g magnetite for pH=9 of leachate.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.1
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• pp.24-31
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• 2003

Objective of this study was to assess rice growth and percolation water salinity under the irrigation of the discharge waters from the municipal wastewater treatment plant and from the industrial wastewater treatment plant as alternative water resources during transplanting season. Three kinds of waters were irrigated; the discharge water from an industrial wastewater treatment plant (DIWT), the discharge water from the municipal wastewater treatment plant (DMWT), and groundwater. Concentrations of $COD_{er}$, $NH_4{^+}_-N$, $Mn^{2+}$, and $Ni^+$ in DIWT, SS content and $PO_4-P$ concentrations in DMWT were higher than those of reuse water criteria of other country for agricultural irrigation. The plant height in the irrigation of DMWT was shorter by 2 cm than the groundwater irrigation except for 10 days irrigation. However, the number of tillerings was not significantly different between DMWT and the groundwater. For the harvest index, there were no significant difference between DMWT and DIWT for 20 days irrigation, but slightly higher in DIWT than that of DMWT for 30 days irrigation regardless of soil types. The salinity of percolation water in the rhizosphere with irrigation of DIWT had more twofold than DMWT, but SAR value from DMWT had no significantly different from the groundwater irrigation. The average $EC_i$ values in the rooting zone irrigated with DIWT and DMWT for 30 days after rice transplanting were 4.7 and $3.4dS\;m^{-1}$ in clay loam soil, and were 3.5 and $2.5dS\;m^{-1}$ in sandy loam soil, respectively. There was dramatic decrease in $EC_i$ value at 30 days after rice transplanting even though $EC_i$ of DIWT had more twofold than DMWT. However, $EC_i$ from DMWT had no significant difference from the groundwater. Therefore, it might be considered that there was limited possibility to irrigate DMWT to overcome drought injury of rice transplanting season in paddy field.

• Korean Journal of Soil Science and Fertilizer
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• v.24 no.4
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• pp.265-271
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• 1991

This study was crried out in order to changes of soil salinity in the Kyehwa saline paddy soil from 1978 find out the to 1988. Surveyed soil was Munpo, Gwanghwal, Yeompo, Hasa series and distribution ratio of those area was 51.2%, 16.6 %, 30.2 %, 1.0 % respectively on the 2,500ha. In the cultivated field, the ratio of desalinization was increased in accordance with rice cultivating years but desalization was not conduct after six years in the uncultivated field. Soil salinity of Summer(during cultivation) and Fall(after cultivation) were 52.3 %, 62.5 % respectively as compare with Spring(before cultivating) and about changes of soil salinity according to different soil depth, underground layer 20-40cm and 40-60cm were raised the rate 28.4 % and 66.2 % in accordance with top soil.