• Korean Journal of Organic Agriculture
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• v.26 no.4
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• pp.731-743
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• 2018

This study was conducted to evaluate the effects of green manures and complemental fertilization with oil cake or liquid fertilizer on growth and nitrogen use efficiency of Chinese cabbage cultivated in organi systems. Field experiments were carried out at the National Institute of Agricultural Science in Suwon, South Korea from 2012 to 2014. Two green manure crops, Crotalaria and Hairy vetch, was cultivated in summer and in winter, respectively. The application methods of the green manure consisted of three tillage systems (overall tillage, partial tillage and no tillage). Oil cake and liquid fertilizer were used as complemental fertilizer. The results showed that when used as covering material in the upland soil without tillage, green manure fertilization was more effective in increasing growth and yield of Chinese cabbage than when incorporated into soil. It was possible to grow and harvest Chinese cabbage in the spring season by the application of hairy vetch as winter green manure. The higher yield of Chinese cabbage with green manure application was caused by the lower incidence rate of soft rot and tip-burn. The yield of the Chines cabbage that received green manure applications over two consecutive seasons followed by the supplemental fertilization with oil cake was similar to that of the conventional chemical fertilization. Following a single season green manure application in summer, however, the yield of cabbage was only about 70% of the conventional treatment. Green manure cultivation with additional liquid fertilization produced a yield similar to the conventional fertilization treatment, soil inorganic nitrogen concentration remained stable and the nitrogen use efficiency increased in the green manure applied soil. In conclusion, the organic cultivation of Chinese cabbage in the autumn season could be outperformed in the upland soil receiving two seasons (winter and summer) of green manure fertilization followed by the supplemental fertilization with liquid fertilizer.

• Korean Journal of Food Science and Technology
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• v.40 no.5
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• pp.485-490
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• 2008

In this study, organic tea leaves were characterized with the aim of developing an organic beverage process. The green tea leaves grown using organic farming techniques were collected in Haenam, Korea. Catechins in green tea leaves were extracted by chloroform and ethyl acetate and these were then analyzed quantitatively and qualitatively by HPLC (high pressure liquid chromatography). The color and pH values of the green tea extracts were also measured. The catechin levels of April-harvested, May-harvested and June-harvested, semi-fermented leaves at 0.5% were 66.24, 29.19, 57.11, and 5.27 ${\mu}g/mL$, respectively. Among the detected catechins, the level of (-)-epigallocatechin gallate was the highest while that of (-)-epigallocatechin was not detected. The June-harvested leaves were selected as raw material for development of the green tea beverage, based on the levels of catechins, economic viability and yield of tea extract. As the level of extract increased, the levels of catechins of 0.1, 0.2, 0.5% also increased by 1.5, 11.78 and 41.01 times. From the results of the sensory evaluation of June-harvested leaf-extract, the sensory score of color was the highest in 0.1%, while the flavor and overall quality were the highest in 0.2%.

• Korean Journal of Organic Agriculture
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• v.25 no.1
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• pp.187-201
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• 2017

This study was conducted to elucidate the effect of mulching materials on growth characteristics, saponin contents and antioxidant activity of Platycodin grandiflorum Ridix roots for organic farming. Plastic film, sawdust and rice bran were treated by mulching with several different methods after transplanting P. grandiflorum Radix. In root length, when plastic film plot, sawdust plot and rice bran plot were treated, root length was recorded the highest scores (24.0~27.5 cm) in plastic film plot and sawdust plot. Root width was recorded the highest score (30.0 mm) in plastic film plot. Also, the number of fine-roots was the highest in plastic film plot (36.0). Fresh weight, which affects directly yield, was the highest in plastic film plot (130 g/plant). The contents of platycodin D3 and deapioplatycodin D were shown to 111.2 and 48.1 mg/100 g, the highest values were observed in sawdust plot. The total polyphenol and flavonoid contents were recorded the highest scores (11.0 and 8.6 mg/g, respectively) in plastic film plot. In this study we confirmed that there were differences among mulching materials in growth characteristics, saponin contents and antioxident activity of P. grandiflorum roots.

• Korean Journal of Environmental Agriculture
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• v.31 no.4
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• pp.368-374
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• 2012

BACKGROUND: The urgency of feeding the world's growing population while combating soil pollution, salinization and desertification requires suitable biotechnology not only to improve crop productivity but also to improve soil health through interactions of soil nutrient and soil microorganism. Interest in the utilization of microbial fertilizer has increased. A principle of nature farming is to produce abundant and healthy crops without using chemical fertilizer and pesticides, and without interrupting the natural ecosystem. Beneficial microorganisms may provide supplemental nutrients in the soil, promote crop growth, and enhance plant resistance against pathogenic microorganisms. We mixed beneficial microorganisms such as Bacillus sp. Han-5 with anti-fungal activities, Trichoderma harziaum, Trichoderma longibrachiatum with organic material degrading activity, Actinomycetes bovis with antibiotic production and Pseudomonas sp. with nitrogen fixation. This study was carried out to investigate the mixtures on the soil microflora and soil chemical properties and the effect on the growth of lettuce and cucumber under greenhouse conditions. METHODS AND RESULTS: The microbial mixtures were used with each of organic fertilizer, swine manure and organic+swine manure and compared in regard to changes in soil chemical properties, soil microflora properties and crop growth. At 50 days after the treatment of microorganism mixtures, the pH improved from 5.8 to 6.3, and the EC, $NO_3$-Na and K decreased by 52.4%, 60.5% and 29.3%, respectively. The available $P_2O_5$ and $SiO_2$ increased by 25.9% and 21.2%, respectively. Otherwise, the population density of fluorescent Pseudomonas sp. was accelerated and the growth of vegetables increased. Moreover, the population density of E. coli and Fusarium sp., decreased remarkably. The ratio of bacteria to fungi (B/F) and the ratio of Actinomycetes bovis to fungi (A/F) increased 2.3 (from 272.2 to 624.4) and 1.7 times (from 38.3 to 64), respectively. Furthermore, the growth and yield of cucumber and lettuce significantly increased by the treatment of microorganism mixtures. CONCLUSION(S): These results suggest that the treatment of microorganism mixtures improved the chemical properties and the microflora of soil and the crop growth. Therefore, it is concluded that the microorganism mixtures could be good alternative soil amendments to restore soil nutrients and soil microflora.

• Korean Journal of Organic Agriculture
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• v.29 no.1
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• pp.111-123
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• 2021

This study was conducted to investigate the growth characteristics of strawberries and N₂O emission by treating the compost for each type of livestock manure, which was an organic farming material, as a basal fertilization in plastic film house. Livestock manure compost, which made from cattle manure, swine manure, and poultry manure as raw materials, were applied to this experiment, treated by mixing or single on the basis of nitrogen content with the standard amount of fertilizer for strawberries. Total emission of N₂O were 10.7% higher than those in poultry manure compost treatment compared to the inorganic fertilizer treatment, but 16.5~41.9% lower than those in other livestock manure compost treatment. The period of N₂O emission mainly was up to the 17th day after fertilizer application, accounting for 70~87% of the total amount of discharge, and 13~30% of the total amount was emitted for 158 days later. N₂O emission was decreased significantly NH₄⁺-N content in the soil, and increased NO₃^--N. As compared with control, the number of leaves, leaf width and crown diameter of livestock manure compost treatments were not significantly different, leaf length of cattle+poultry, cattle+ swine, swine+poultry treatment higher, and SPAD (soil plant analysis development) values of cattle+poultry treatment highest. There was no significant difference in weight and sugar content of strawberry fruits among treatments.

• Korean Journal of Environmental Agriculture
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• v.34 no.2
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• pp.128-133
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• 2015

BACKGROUND: Plant extracts have been used as environment friendly agricultural materials for organic farming in South Korea. However safety evaluation on the plant extracts was not properly tested. The aim of this study was to evaluate safety of the extracts from Melia azedarach, Nerium indicum and Coptis chinensis on cultivating rice. METHODS AND RESULTS: Pant extarcts 300-fold diluted were treated on rice, and residues of M. azedarach, N. indicum and C. chinensis were determined. The analytes from the rice samples were detected by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). The method was validated, and good linearities ($r^2=0.995-0.998$), specificity, and recoveries were obtained. Limits of detection were 0.01 mg/kg for all of the target compounds. Recoveries were 79.3-118.3% at 0.1 mg/kg and 75.2-111.5% at 0.5 mg/kg. The residue levels were below 0.030 mg/kg for azadirachtin, 0.320 mg/kg for oleandrin and 1.460 mg/kg for berberine. CONCLUSION(S): The extracts of M. azedarach, N. indicum and C. chinensis contained azadirachtin, oleandrin and berberine as an active ingredient, respectively. The residue of three active ingredients dramatically decreased after treatment in all fruits, stems and roots of rice.

• Journal of Wetlands Research
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• v.9 no.2
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• pp.71-84
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• 2007

Masan Bay is a representative semi-closed bay acted as a sedimentation reservoir with a slow current velocity and a poor water circulation in Korea. The pollutants from terrestrial sources into the Masan Bay have apparently environmental pollution problems, such as eutrophication, red tied, and hypoxia. In this study, An ecological modeling work was performed to estimate the material circulation including the growth of bivalve in ecosystem. Furthermore, the effect of water purification was calculated by filter feeding bivalve to particulate organic matter just like COD and phytoplankton. And Water quality management strategy by bio-purification of bivalve is derived through selection of location, quantification of bivalve aquaculture farm. The results showed that the optimum location for bivalve farming is where phytoplankton accumulation by physical processes is maximized and the optimum density and area of bivalve are 35 individuals $m^{-3}$ and ca. 500 hectare, respectively. When assuming conditions for the optimum growth of bivalve, COD could decrease by up to 18% even without other reduction of pollution loads.

• Journal of Plant Biology
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• v.17 no.2
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• pp.53-62
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• 1974

A study was made on the primary production of Lake Changjamot during the spring season of 1973 by menas of the oxygen method. The stratification of temperature and dissolved oxygen were formed in May with the stratified structure of phytoplankton. The range of Secchi disc transparency was from 0.8m to 2.3m during the nine months of this investigation, which was begun in January, 1973. The value was lowest in early June when the phytoplankton blooming reached the peak. The concentration of PO4-P, NH3-N, NO3-N and NO3-N was reduced at the beginning of the phytoplankton blooming and increased again after May except PO4-P. It might have been caused by the inflow of the nitogenous fertilizer from the surrounding agricultural area since May when farming was started. The total amount of chlorophyll-a in the entire water column varied from 25mg/$m^2$ to 277mg/$m^2$ from January till September with the maximum value occurring in early June. These values show a considerable eutrophication of the in comparison with the data obtained in 1969. The daily gross production in the lake varied from a low of 655mgC/$m^2$ to a high of 2,859 mgC/$m^2$ during the spring season and this corresponds to the variation of the amount of chlorophyll. The total amount of daily respiration varied from 650mg C/$m^2$ in winter to 2,307 mg C/$m^2$ in late spring and exceeds gross primary production especially in late May showing the negative balance of daily production and consumption of organic material at that time. In conclusion, Lake Changjamot is a fairly productive and a moderately autotrophic lake and has been eutrophicated much during the past four years.

• Korean Journal of Environmental Agriculture
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• v.23 no.4
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• pp.203-210
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• 2004

This study was conducted to assessment organic compound and bioassay (density of inhabited animal, fluctuation of predominant fungi, and survival ratio of earthworm) for finding damage on red pepper by heavily amount application of sludges in soil, which was treated with 3 pharmaceutical byproducts and a cosmetic industry wastewater sludge as raw materials of compost, and for establishing estimation method. HEM contents in the soil treated with pharmaceutical byproducts sludge2 (PS2) and cosmetic sludge (CS) were 0.51, 1.10 mg/kg respectively. PAHs content of PS2 treatment in the soil was 3406.8 ug/kg on July 8. In abundance of soil faunas, the pharmaceutical byproducts sludge2 treatment was the most highest. The next was decreased in the order of pig manure (PM) and the cosmetic sludge treatment. However the other pharmaceutical sludge treatments were remarkably reduced populations of soil inhabited animals. In upland soil treated with organic sludges, the numbers of bacteria and fungi of the pharmaceutical sludge treatment were 736, 909 cfu/g and those of the cosmetic sludge treatment were 440, 236 cfu/g, respectively. The pharmaceutical sludge treatments and the cosmetic sludge treatment in identification of predominant bacteria were not any tendency to compare with non fertilizer and pig manure treatments, but they had diverse bacteria than NPK treatment. In microcosm tests, the survival of the tiger earthworm in five soil samples was hardly affected against the soil of PSI (20%) after three months treated in the upland But after six months, survival of PS1 was 80%. At present, raw material of compost was authorized by contents of organic matter, heavy metal (8 elements), and product processing according to 'The specified gist on possible materials of using after analysis and investigation among raw materials of compost', however, for preparing to change regulation of raw material of compost and for considering to possibility of application, this study was conducted to investigate toxic organic compound and bioassay methods using inhabited animal, fungi, and earthworm without current regulation.

• The Korean Journal of Community Living Science
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• v.27 no.4
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• pp.891-906
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• 2016

This study examined the working site environment of Korean native cattle raising farmers and their actual condition of wearing personal protective equipment as part of preventing disasters during agricultural work. To this end, 160 Korean cattle raising farmers were surveyed and a site visit was performed on 10 farms. According to an examination of the cattle breeding environment, the major harmful factors were in the following order: fine dust (12.8%), organic feed dust (10.3%), contact with cattle (9.7%), manure (8.2%), germs and viruses (8.1%), harmful gases (7.4), contact with obstacles (6.7), and temperature (6.6%). The current status of the rate of wearing protection was in the order of gloves (20.9%), working hats (19.7%), boots (19.6%), masks (10.9%), protective clothing (8.9%), and specialized working clothing (6.6%). Nevertheless, most Korean cattle raising farmers recognized the risks when they did not wear protective equipment and the need for wearing protectors, but they mostly did not wear personal protective equipment due to a lack of knowledge on the selection of appropriate personal protective equipment and the discomfort they experience when they put on protectors. Even when they put on protective equipment, 38% was inappropriate for the farming work environment. Given the research results, improvements on and the development of specialized working clothing and personal protective equipment to protect farmers from harmful and dangerous materials from the cattle nurturing environment is necessary. Overall, based on the study data, objectified data collection, a determination of the necessary performance elements of personal protective equipment, and R&D will be needed through an on-site current status investigation.