• Journal of Preventive Medicine and Public Health
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• v.43 no.6
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• pp.535-542
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• 2010

Objectives: Exposure assessment is a major challenge faced by studies that evaluate the association between pesticide exposure and adverse health outcomes. The objective of this study was to investigate the reliability of information that farmers self-report regarding their pesticide use. Methods: Twenty five items based upon existing questionnaires were designed to focus on pesticide exposure. In 2009, a selfadministrated survey was conducted on two occasions four weeks apart among 205 farmers residing in Gyeonggi and Gangwon provinces. For a reliability measure, we calculated the percentage agreement, the kappa statistics and the intraclass correlation coefficient (ICC) between the two reports according to the characteristics of the subjects. Results: Agreement for ever-never use of any pesticide was 96.4% (kappa 0.61). For both 'years used' and 'age at the first use' of overall pesticides, high agreement was obtained (ICC: 0.88 and, 0.78, respectively), whereas those of 'days used' and 'hours used' were relatively low (ICC: 0.42 and, 0.66, respectively). The kappa value for the use of personal protective equipment ranged from 0.46 to 0.59, and hygiene activities came out at 0.19 to 0.37. The agreement for individual pesticide use ranged widely and there was relatively low agreement due to the low response rates. The reliability scores did not significantly vary according to gender, age, the education level, the types of crop or the years of farming. Conclusions: Our results support that carefully designed, self-reported information on ever-never pesticide use among farmers is reliable. However, the reliability of data on individual pesticide exposure may be unstable due to low response rates and needs to be refined.

• Korean Journal of Organic Agriculture
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• v.24 no.3
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• pp.511-524
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• 2016

This study was conducted to elucidate the effect of organic fertilizer on growth characteristics, saponin contents and antioxident activity of Platycodin grandiflorum Ridix roots for organic farming. As basal fertilizers, chemical fertilizer, mixed organic fertilizer, bacterial cultures and fermented oil cake and decomposed manure were treated based on 3 kg/10a level before transplanting Platycodin grandiflorum Ridix. In root length, when chemical fertilizer plot and mixed organic fertilizer plot were treated, root length was recorded the highest scores (25.3 and 24.0 cm) Root width was recorded the highest score (26.6 cm) in chemical fertilizer plot. The number of fine-roots was the highest in mixed organic fertilizer plot and chemical fertilizer plot (20.0 and 17.0), respectively. Fresh weight, which affects directly yield, was the highest in organic fertilizer plot (55.7 g/plant). The content of Platycodin D was shown to 327.4~373.8 mg/100 g, the highest values were observed in organic fertilizer plot. The total polyphenol and flavonoid contents were recorded the highest scores (15.5 and 15.3 mg/g, respectively) in organic fertilizer plot. In this study we confirmed that application of organic fertilizer was effective to increase yield and pharmacological effect through increase of the number of fine-roots with high saponin contents.

• Journal of Soil and Groundwater Environment
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• v.21 no.6
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• pp.179-191
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• 2016

In addition to the measurement of the concentration of soil contaminants, the new idea of indicative parameters was proposed to validate the remedial works through the monitoring for the changes of soil characteristics after applying the clean up technologies. The parameters like CFU (colony forming unit), pH and soil texture were recommended as indicative parameters for land farming. In case of soil washing, water content and the particle size distribution of the sludge were recommended as indicative parameters. The sludge is produced through the particle separation process in soil washing and it is usually treated as a waste. The parameters like water content, organic matter content, CEC (cation exchange capacity) and CFU were recommended as indicative parameters for the low temperature thermal desorption method. Besides the indicative parameter, sampling methods in stock pile and the optimal minimum amount of composite soil sample were proposed. The rates of sampling error in regular grid, zigzag, four bearing, random grid methods were 17.3%, 17.6%, 17.2% and 16.5% respectively. The random grid method showed the minimum sampling error among the 4 kinds of sampling methods although the differences in sampling errors were very little. Therefore the random grid method was recommended as an appropriate sampling method in stock pile. It was not possible to propose a value of optimal minimum amount of composite soil sample based on the real analytical data due to the dynamic variation of $CV_{fund{\cdot}error}$. Instead of this, 355 g of soil was recommended for the optimal minimum amount of composite soil sample under the assumption of ISO 10381-8.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.62 no.1
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• pp.73-78
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• 2017

This study was conducted to elucidate the effects of mulching materials on root growth characteristics and weed occurrence of Platycodon grandiflorum transplants (3 years old) in organic farming. After transplanting, roots were mulched with one of three mulching materials (biodegradable film, sawdust, or rice husks) or a control (no mulching). The average root diameter of all mulching groups was 28.1 mm, which was 5.1 mm thicker than the no-mulching treatment. Roots with the biodegradable film treatment were the thickest at 30.9 mm. Root length was the shortest, 22.0 cm, with rice husk mulching. The number of rootlets was the highest with film mulching (36.0 rootlets/root) and the lowest with no mulching. For root fresh weight, which directly affects yield, the average of treated and untreated roots was 100 and 56 g/root, respectively. The highest fresh weight was in the biodegradable film plot (130 g/root). The mulching treatment groups showed a weed inhibition effect compared with the no-mulching treatment. The dominant weeds with the no-mulching treatment were Setaria viridis and Digitaria ciliaris, and that with the mulching treatment was Setaria viridis. Average annual weed occurrence across all treatments was 72%. Weed occurrence was the highest with the no-mulching treatment ($125weeds/m^2$), and there were no weeds with the biodegradable film treatment.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.3
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• pp.185-191
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• 2012

Most of Korean farms have been developed in the semi-closed bay, and its position is very vulnerable to the coastal contamination due to the long term and the high density. So, mariculture management is very essential for the sustainable aquaculture. Some of the specific ways would be the assessment of the optimal stocking density for mariculture management zone and this has to consider both the suitable site selection and the assessment of ecological carrying capacity. Habitat suitability index(0.0 totally unsuitable habitat, 1.0 optimum habitat) and ecological indicator(Filtration pressure indicator) was used to assess the stocking density for oyster farms in Geoje-Hansan Bay. Geoje Bay showed the higher habitat suitability index value 0.75 than Hansan Bay 0.53, indicating that Geoje Bay is more suitable for oyster farming. Ecological indicator showed different stocking density according to the coastal characteristics in Geoje-Hansan Bay. Consequently, it is desirable that the stocking density in Geoje Bay should reduce average 40% and Hansan Bay, average 60% than present, in order to meet the ecological carrying capacity. The assessment of the stocking density could solve various problems such as the coastal contamination, environmental aggravation and the productivity decrease and this study could be a scientific basis to establish the policies for mariculture management.

• Journal of the Korean Society for Marine Environment & Energy
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• v.13 no.4
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• pp.279-287
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• 2010

To identify characteristics of the water quality at Goseong bay, we analyzed long term monitoring data collected at surface and bottom water which was accumulated during the period of 1987~2009. The result showed that the waters of Goseong bay represented mesotrophic level that is based on chlorophyll-a, DIP and DIN and seasonal average of COD that indicates level by the COD criteria. This analysis can be translated that the waters is comparatively clean even though the waters is in the closed bay that slowly diffuses influx mass. We also did the time series analysis, correlation analysis and regression analysis on the moving average of the water parameter at Goseong bay. According to the results, DIP showed a increasing trend as time passed while DIN was on a decreasing trend under the same condition. In the waters of Goseong bay, the phyto-plankton growth was shown to be limited by DIN concentration. The chlrophyll-a was at the peak in August, at $4.60{\mu}g/L$. As the seasonal average and index were the highest in November, it was understood that the balance of nutrient at Goseong bay was dependent more on inner factors, ie, mass farming of aquatic species and release of bottom sediment rather than on inflow of fresh water. Accordingly, it is needed to consider the balance of nutrient like DIP and DIN to manage the water quality or estuaries at Goseong bay.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.9
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• pp.504-512
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• 2016

In this study, we investigated the environmental impact of organic and conventional paddy by monitoring soil properties and water quality. We sampled and analyzed topsoil (0~15 cm), subsoil (15~30 cm), and water of organic and conventional paddy fields in Yongin and Anseong, South Korea. The statistical significance between groups was determined by Duncan's multiple range test. The results show that T-P concentrations in both topsoil and subsoil of Anseong paddy were higher than those of Yongin paddy. The significant difference of T-P between organic and conventional paddy was observed in Anseong but not in Yongin. T-N of organic paddy soil was lower than that of conventional paddy in both Anseong and Yongin region. Water content for subsoil of organic paddy in Anseong was significantly different from others, which is consistent with the results of silt-clay content. pH and EC of water in conventional paddy were higher than those in organic paddy. In Anseong, COD, T-P, and $PO_4-P$ concentration of conventional paddy were higher than those of organic paddy. The regression analysis presented that there were no significant relationship between soil properties and water quality data except T-N.

• Journal of Agricultural Extension & Community Development
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• v.21 no.3
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• pp.53-89
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• 2014

Immigrant farmers work in various social and economic fields of activity, settling in their rural community. In this study, I inquired into the way of acting of immigrant farmers, based on the texts which were made in the precedent studies. The texts were transcriptions that were made by interviews with immigrant farmers. I classified immigrant farmers' activities into 8 groups that were related to; farming, nonfarm business, off-farm business, volunteering, participating in community organization, lifelong learning, leisure and social interaction in everyday life. And, I tried to capture the characteristics and meanings of those activities. The implications from this analysis are as followings: 1) most of immigrant farmers have small family farm so that they need nonfarm or off-farm jobs, 2) pluri-acivities of immigrant farm households can contribute to their community's economic viability, 3) their economic activities should be observed carefully in the perspective of self-help approach in community development as well as farm households' livelihood strategy, 4) immigrant farmers have many difficulties to participate in community, nevertheless community participation will improve the social capital, 5) gender-sensitive policy should be developed.

• Korea journal of population studies
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• v.23 no.2
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• pp.39-77
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• 2000

The paper examines non-agricultural occupations of Korean immigrants in the Russian Far East from 1860s to 1930s. First of all, theoretical perspectives regarding immigrants\` job selection and positions in the labor market such as cultural theory, segmented labor market theory, human capital theory, and ethnic enclave theory were reviewed and then how these theories can be applied to various jobs of Korean immigrants including mining, fishing, small business, service, and miscellaneous jobs was studied. Next. this article points out that those theories cannot explain both supply and demand sides of migration simultaneously, suggesting the need to integrate two sides of migration. In order to fill out this gap in the literature, this paper suggests the integrative approach which combines supply side and demand side of migration. According to this model, several factors in the non-agricultural jabs which were affecting Korean immigration in the Russian Far East. were identified and discussed in relation with existing theoretical perspectives. Finally this paper concludes that, in order to understand Koran migration in the Russian Far East properly, we have to take into consideration simultaneously both supply-sided factors of immigration including farming-oriented characteristics of Koreans, Korean socio-economic problems preceding immigration, and self-dependent tendencies of Korean immigrants and demand-side factor like the Russian migration policy to the immigrants and various regional situations in the Russian Far East.

• Journal of the Korean Geographical Society
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• v.29 no.3
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• pp.340-359
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• 1994

This study intends to describe the characteristics of the transformation of the rural society by tracing the changing social and economic processes of traditional clan villiage (Yeolmi-ri, Silchon-myeon, Kwangju-gun, Kyunggi-province) in the suburbs of Seoul Metropolitan Area. Rural society has experienced serious change of the social structure by the ever expanding urbanization and industrialization since 1960's. The suburbs of Seoul Metropolitan Area is the representative case area of such transformation. This study analyzed various chracteristics of population structure of a villiage, the processes of residential movement and the occupational shift of each household of the villiage in terms of household's life-history collected by interviewing with each household. And the whole households of a villiage is divided by two groups of the native clan group and the non-dan in-migrant group. The results of this study are summarized as follows. 1) This villiage is located within a lineal distance of 40km and a time distance of about 30 to 40 minutes, adjoined dy the Joongbu(중부) national highway, the Kyungchoong (경충) industrial road, the local road between Yangpyuna(양평) and Gonjiam(곤지암) and having a advantageous iocational linkage to Seoul capital city. 2) It is a typical traditional dan villiae constituted of dan family Gu(구) one of whose ancestors had appointed to the prime minister of Chosun Dynasty, and until 1979, 56 out of 60 families of the villiage households were clan families. 3) Since 1979, as the villiage invaded by the out-movement of the small scale manufacturing industries from Seoul capital city, labours moved in this vallige from outside and increased villiage size up to 203 households in 1993, consequently the constitutional proportion between the native clan group and the non-clan in-migrant group was reversed up to 28% vs 72% deepening the sociological heterogeneity. 4) Because of the small scale of industries in this villiage and the vicinity with the city of Seoul, the population turnover of this villiage is very high. The turnover frequency is firstly high within same administrative district of gun(군) level and secondly high between this villiage and the city of Seoul. Thus short-distance movement is identified. 5) There is a close correlation between the residential movement and the occupational shift. The most numbers of non-farm native group have the experiences of migration while the members of native farming group don't shift both the job and the place of residence. The inmigrant group had several migration experiences but few occupational shifts. Thus occupatioanl shift is high for the native group while residential shift is high for the in-migrant group. It is concluded that the change proceeded in Metropolitan suburbs was not directed to form the traditional rural village as 'gesund Gebiet' with respect to the ballance among the economic, cultural and environmental adequency.