• Asian Journal of Turfgrass Science
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• v.7 no.2_3
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• pp.55-60
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• 1993

Soil profile was well developed into four horizons, $A_1$, $A_3$, $B_2$and C at 100cm-depth in most four golf courses in Kyonggi province. Distribution of root system of Korean lawngrass was abundant in dark yellowish or yellowish brown $A_1$ horizon with low hardness(8~14mm yamanaka scale), moderately in yellowish brown $A_3$ horizon with moderate hardness(16~23mm) rarely in $B_3$horizon(15~60cm depth) and no in C horizon. Optimum soil hardness for good root growth of Korean lawngrass appeared to be less than 16mm mineral nutrient contents. Such as Ca++, Mg++, K+, Mn++ and Fe showed relatively higher concentration in lower horizon indicating the leaching of minerals. The increasing tendency of soil pH with depth seemed to the result of mineral leaching. There was significant positive correlation between Ca+Mg and pH, manganese content appeared to be too high(261~789ppm) in $A_1$ horizon. The contents of organic matter and phosphorus were bight in $A_1$ horizon and greatly varied among golf courses.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.2
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• pp.66-73
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• 2004

As one of the typical farming practices in the sloped upland in Pyeongchang and Hongcheon area, application of piling with coarse saprolite materials has been practiced by farmers for several reasons such as reduction of damage by monocropping, better development of plant roots, and better drainage. However, adverse effect on application of coarse saprolite soil materials to environmental aspects should not be ignored. Therefore, this research was conducted to evaluate the physicochemical properties of coarse saprolite materials in upland fields in Pyeongchang area. According to particle size distribution of coarse saprolite materials, averaged gravel contents for Pyeongchang and Hongcheon county were 16.7 and 25.3%, respectively. There was no significant difference in gravel contents by soil depth, and CV values for each particle size ranged from 20 to 40%, which implied that application of coarse material with similar properties. When we compared CEC values of dressed soil with or without considering gravel content, CEC values decreased as increasing gravel contents. The penetration resistances were 0.04-7.48 MPa at the 0 to 10 cm surface soil, and 0.10 to 8.80 MPa at the depth below 11 cm. The bulk density of the soil was $1.15g\;cm^{-3}$ at the surface soil and 1.29 to $1.35g\;cm^{-3}$ at the soil depth below 10 cm. The organic matter content, cation exchange capacity, and avaliable $P_2O_5$ concentrations of soil in upland where piling with saprolite materials of Pyeongchang area applied were $12.4g\;kg^{-1}$, $7.1cmol_c\;kg^{-1}$, and $526mg\;kg^{-1}$, respectively. Cation exchange capacity was lower than that of averaged Korean upland soil, while available $P_2O_5$ concentration was relatively higher than that of averaged Korean upland, which indicated high input of various fertilizers.

• Korean Journal of Environmental Agriculture
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• v.38 no.4
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• pp.262-268
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• 2019

BACKGROUND: To investigate mineralization characteristics of organic resources in the soil, five materials (rice straw, cow manure sawdust compost, microorganism compost, mixed oil-cake, and amino acid fertilizer) were treated according to the nitrogen content, and an indoor incubation experiment was conducted for 128 days. The results of this analysis were applied to determine the nitrogen mineralization pattern of these organic resources. METHODS AND RESULTS: During the constant temperature incubation period, the nitrogen net mineralization rate of the organic resources was the highest in the amino acid fertilizer with the highest nitrogen content, and the lowest in the rice straw with the lowest nitrogen content. A positive correlation (0.96) was observed between the potential nitrogen mineralization rate and total nitrogen content. The mineralization rate constant, k, was negatively correlated with the organic matter (-0.96) and carbon content (-0.97). The nitrogen mineralization rate during the first cropping season, as estimated by the model, was 6.6%, 11.6%, 30.9%, 70.7%, and 81.0% for the rice straw, the cow manure sawdust compost, the microorganism compost, the mixed oil-cake, and the amino acid fertilizer, respectively. CONCLUSION: The nitrogen mineralization rate varies depending on the type of organic resources or the nitrogen content; thus, it can be used as an index for determining the nitrogen supply characteristics of the organic resource. Organic resources such as compost with low nitrogen content or those undergoing fermentation contain organic nitrogen. Organic nitrogen is stabilized during the composting process. Therefore, as the nitrogen mineralization rate of these resources is lower than that of non-fermented organic resources, it is desirable to use the fermented organic materials only to improve soil physical properties rather than to supply nutrients for the required amount of fertilizer.

• Journal of Soil and Groundwater Environment
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• v.17 no.2
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• pp.54-61
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• 2012

In this study, the adsorption of $Cu^{2+}$ from aqueous solution by the biochar derived from woody biomass at different pyrolysis temperatures has been investigated. The woody biomass wastes used in this study were branch of willow ($Salix$ $koreensis$ $Andersson$) and bark of chestnut ($Castanea$ $crenata$ $var.$ $dulcis$). Three biochar samples prepared by heating each biomass at temperature of $300^{\circ}C$, $500^{\circ}C$, and $700^{\circ}C$were tested for the adsorption capacity of Cu. Also the physicochemical properties of the developed biochars were studied using different characterization techniques such as FT-IR, SEM, BET surface area, and cation exchange capacity (CEC). The adsorption of Cu could be well described by Langmuir model for both willow and chestnut biochars with $R^2{\geq}0.98$. The maximum adsorption capacities of the biochar produced at $700^{\circ}C$ from the Langmuir equation were found to be 12.5 mg $g^{-1}$ and 16.9 mg $g^{-1}$ for willow and chestnut, respectively. Chestnut biochar was found to interact more effectively with the active sites available for Cu, resulting higher removal of Cu(II) than wiloow biochar. Ion exchange and surface complexation found to be the main mechanisms involved in the adsorption process. This study demonstrated the feasibility of the biochars derived from woody biomass to be as a low-cost potential adsorbent for heavy metals as Cu(II) removal in aquatic system.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.1
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• pp.1-6
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• 2004

Agricultural recycling of livestock wastes by composting has lots of beneficial effects on crop production and soil fertility. Most of composts are made from pig manure and water content controller such as saw dust, bark, rice hulls etc. by aerobic processing. But the insufficient supply of saw dust, bark etc. cause the indiscreet use of industrial waste having heavy metals and toxic synthetic chemicals. This research investigated the present quality status of organic by-product fertilizers, and suggested the way of quality interpretation under the statistical approaches based on median, mean and weighted average value. Since the data of one hundred of samples for heavy metal contents (Cd, Pb, Cu, and Cr) and OM/N showed extremely left-skewed distribution, the median was more useful than the mean in representing the characteristics of distribiition for each items. The weighted average value will be a useful index for the quality based on the total amount of producing.

• Journal of Soil and Groundwater Environment
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• v.13 no.3
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• pp.52-58
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• 2008

Mn-impregnated activated carbon (Mn-AC) prepared at different conditions was applied in the treatment of synthetic wastewater containing both organic and inorganic contaminants. Phenol and As(III) was used as the representative organic and inorganic contaminants, respectively. After evaluation of the physicochemical characteristic and stability of Mn-AC, oxidation of As(III) as well as adsorption of phenol by activated carbon(AC) and Mn-AC were investigated in a batch reactor. To investigate the stability of Mn-AC, dissolution of Mn from each Mn-AC was measured pH ranging from 2 to 4. Although Mn-AC was unstable at a strong acidic condition, the dissoluted Mn was below 3 ppm at pH 4. XRD analysis of Mn-AC indicated that the mineral type of the impregnated manganese was $Mn_2O_3$. From the simultaneous treatment of As(III) and phenol by AC and Mn-AC, As(III) oxidation by Mn-AC was greater than that by AC at lower pH, while the reverse order was observed at higher pH. After impregnation of Mn onto AC, 13% decrease of the surface area was observed, causing 8% reduction of phenol removal. Considering removal properties of As(III) and phenol, Mn-AC could be applied in the simultaneous treatment of wastewater contaminated with multi-contaminants.

• Korean Journal of Soil Science and Fertilizer
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• v.17 no.2
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• pp.147-154
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• 1984

Two Fe-hydrous oxide A,B and one Al-hydroxide minerals were synthesized precipitating Fe $Cl_3$ and $AlCl_3$ with alkali solution(NaOH) at pH 6.0, 12.0 and 4.5 respectively, for precise understanding of physico-chemical and surface charge characteristics of soils in which these minerals are dominant. Identification of these final products, effect of free and amorphous materials on X-ray diffraction analysis, particle size distribution and surface change characterics of these minerals were performed. Fe-hydroxide A and B were identified as great deal of X-ray amorphous material and as goethite with large amount of X-ray amorphous material, respectively. Dehydration by oven at $105^{\circ}C$ of these minerals exhibited akaganeite peaks with low X-ray amorphous hump and pure goethite peaks for Fe-hydroxide A and B, respectively. Both minerals, however, turned into hematite upon firing at $550^{\circ}C$. On the other hand, Al-hydroxide identified as mixture of gibbsite and bayerite of around 7:3 ratio. Application of sodium dithionite and ammonium oxalate solutions for removal of free or amorphous Fe and Al from these minerals revealed that only peak intensities of Al-hydroxide system were enhanced upon Al-extraction by oxalate solution even though dithionite solution was much powerful to extract Fe from Fe-hydrous oxide systems. Original(wet) Fe-hydrous oxide A has the highest specific surface and surface charge development(negative and positive), and the greatest amount of less than $2{\mu}m$ sized particles. Specific surface and clay sized particles(less than $2{\mu}m$) of Fe-hydrous oxide A, however, were drastically reduced upon dehydration($P_2O_5$ and oven drying) compare to the rest minerals. The Z.P.C. of these synthetic minerals were 8.0-8.5, 7.5-8.0 and 5.5-6.0 for Fe-hydrous oxide A, B and Al-hydroxide, respectively.

• Proceedings of the Korean Society of Organic Agriculture Conference
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• 2009.12a
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• pp.77-101
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• 2009

Organic farming in Korea has mainly focused on producing vegetables in plastic film house and cereals in paddy field. For high productivity of vegetables and cereals, most Korean farmers have not applied crop rotation in the cropping system. Thus, this study was carried out to evaluate the effects of crop rotation on the yield of red pepper and green onion, the changes in soil fertility and the potential as green manure of rye and hairy vetch. Rye and hairy vetch were cultivated for winter season every year, and directly incorporated into the soil. The yield of red pepper fruits in organic farming using crop rotation (OFCR) decreased 23 to 36% compared with conventional farming system (CFS). Whereas, green onion showed the increased yield of about 13%. In OFCR, total carbon content of soil was higher, however available phosphate content lower than conventional farming. As a result of measuring the bulk density of soil, OFCR and CFS were 1.26 to $1.35Mg/m^3$ and 1.37 to $1.42Mg/m^3$, respectively. Carbon and nitrogen contents of microbial biomass in OFCR were obviously higher compared with the CFS. In the plot cultivated rye for winter season, the weed germination was strongly reduced (about 52 %). Balance of macro nutrient elements, nitrogen and phosphate, in the application of rye and hairy vetch had a minus value. For potassium, the output value was higher than the input one, therefore organic farming under red pepper-rye or hairy vetch systems requires applying additional potassium input. Also, we selected two hairy vetch varieties of cv. Hungvillosa and Ostsaat which can be adapt at Korea climate. In order to estimate a yield of green manures, the weight of shoot and root was measured. The ratio of shoot and root between rye and hairy vetch showed 0.88 and 1.91, respectively. The potential levels of nitrogen, phosphate and potassium which could be supplied from rye were 7.7, 7.8 and 21.9 kg/10a and from hairy vetch were 17.0, 8.6 and 22.9 kg/10a, respectively. So we recommend that cultivating hairy vetch, as a nutrient supplier, and rye, as an amendment to enhance the soil physical property, for winter season be practical method in Korea organic farming system.

• Korean Journal of Environmental Agriculture
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• v.38 no.2
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• pp.83-88
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• 2019

BACKGROUND: In recent years, studies on microplastics have focused on their decomposition in the ocean. However, no studies have been reported on the interaction between microplastics and metal ions in aqueous solutions. Therefore, this study was conducted to evaluate the adsorption capacity of cadmium(Cd) by polypropylene (PP) in aqueous solution. METHODS AND RESULTS: Cadmium adsorption characteristics of PP in aqueous solution were evaluated through various conditions including initial Cd concentration(1.25-25 mg/L), contact time(0.5-24 h), initial pH(2-6) and temperature($20-50^{\circ}C$). Cadmium adsorption fit on PP was well described by Freundlich isotherm model with adsorption capacity(K) of 0.028. The adsorption amount of Cd by PP increased with increasing contact time, indicating that adsorption of PP by Cd was dominantly influenced by contact time. Especially, the removal efficiency of Cd by PP was highest at high temperature. However, the surface functional groups of PP before and after adsorption of Cd were similar, suggesting that adsorption of Cd by PP is not related to surface functional groups. CONCLUSION: Our study suggests that PP affects the behavior of Cd in aqueous solution. However, in order to clarify the specific relationship between microplastics and metal ions, mechanism research should be carried out.

• Korean Journal of Heritage: History & Science
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• v.52 no.3
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• pp.146-159
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• 2019

This study focuses on the understanding of human subsistence and pottery use during ancient times on the Korean peninsula through lipid analysis of potsherds from several major prehistoric settlement sites. Ancient human subsistence has been one of the long-standing topics in Korean archaeology. However, since the high acidity of sediments does not allow long-term preservation of organic remains, we still lack some critical information related to the prehistoric diet. Pottery contains relatively well-preserved organic remains created during past cooking events. Though pottery is one of the most studied material cultures in Korean archaeology, almost no attention has been given to analyzing the pottery itself. This is a surprising omission and represents a serious gap in our understanding of prehistoric technology and subsistence. The analysis of ancient lipids extracted from the pottery matrix using GC-MS and isotope analysis can contribute to our understanding of the true nature of past subsistence strategies. Potsherd samples for the analyses in this study were collected from six prehistoric and early historic settlement sites located in the central part of the Korean peninsula. The results showed that subsistence strategies differed by both location and time period. For example, at Jungdo, an inland open-air Bronze Age settlement site in Chuncheon City, we were able to see the presence of terrestrial mammals. At Gahak-dong, Gwangmyeong City, marine resources were utilized, as the location of the site is not far from the coastline. At the early historic site of Guwol-dong, Incheon City, we were able to detect dairy products. The results of this study suggest that there was utilization of a wider range of resources among ancient dwellers in the central part of the Korean peninsula.