• Journal of Soil and Groundwater Environment
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• v.25 no.3
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• pp.43-51
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• 2020

About 90% of groundwater wells in Jeju Island are reported to be under the threat of contamination by infiltration of the surface pollutants. Most of those wells have improperly grouted annulus which is an empty space between the well and the inner casing. As a remedy to this problem, some of the wells were re-grouted by filling the annulus with cement without lifting an inner casing. In order to evaluate whether this method is appropriate for the geological structure of Jeju Island, two wells (W1 and W2) were selected and this method was applied. The water holding capacity did not decrease while the nitrate levels decreased from 16.8 and 20.2 to 6.8 and 13.8 mg/L in W1 and W2, respectively. The higher nitrate level in W2 is deemed to be influenced by the livestock farms located in the upper area of the well. In addition, transmissivity of the vedose zone was higher in W2 than W1, potentially facilitating the transport of nitrate to the groundwater. The overall result of this study suggests re-grouting of wells for the purpose of protecting water quality of goundwater should take into account geological structure of vadose zone as well as appropriate source control of the contaminants.

• Journal of the Korean Geographical Society
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• v.39 no.4
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• pp.544-561
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• 2004

Weekly monitoring of discharge and water quality in forested and agricultural subcatchments were performed to understand the difference of water quality caused by land uses in Doegwollyong area. Correlations between water quality variables including discharge were analyzed for the same purpose. There was little variation of water Quality in forested subcatchment. On the other hand, the range of water quality variation in agricultural subcatchment was wide due to soil loss and the application of chemical fertilizers and livestock manure. Dissolved oxygen(DO) had strong negative correlation with discharge in both subcatchments. Total nitrogen(T-N) and potassium ion(K$^{+}$) had stronger positive correlation with discharge in forested subacatchment than in agricultural one. On the other hand, total suspended sediments(TSS), total phosphorus(T-P), and chemical oxygen demand(COD) had stronger correlation with discharge in agricultural subcatchment than in forested one. As water pollution of the Doam Lake, especially the increase of T-P is serious, soil conservation is very important to improve water quality. In particular, the loss of soil and nutrients from late June till early July were more serious than any other seasons, therefore it is necessary to apply environmentally sustainable methods of cultivation.n.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1997.11a
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• pp.145-159
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• 1997

Cheju Island is the most attractive resort area in Korea for its exotic landscape, natural beauty, and traditional culture which is quite different from that of the mainland. Until now, most of the recreational facilities and accomodations have been constructed along the coastal areas. Recently, mid-mountain area has been under very heavy development pressure because it is suitable for new sites for tourism facilities and the land price in the coastal area is very high. The mid-mountain area is the land located 200-600m above the sea level. It is a major source of water supply for the island and has exotic scenic beauty, which cannot be found in mainland but it is the area very vulnerable to water pollution Therefore, it is very important to manage this area based on the concept of environmentally sound and sustainable development in order to meet ever increasing demand for the land development The purposes of this project are: 1) to establish Geographic Information System for the whole island, 2)to formulate environmentally sound landuse plat However, There has been accuracy of the original map, defining criteria of analysis, updating of the data were identified for future tasks to be studied.

• Journal of agriculture & life science
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• v.44 no.6
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• pp.121-132
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• 2010

Soybean farms in Changnyeong were selected for hazard analysis to establish the Good Agricultural Practices (GAP) model of soybean, and physical, chemical(heavy metal) and biological(sanitary indications, foodborne pathogens) hazard analysis for cultivation environment (soil, water) was carried out. First, bow which is able to be mixed in soil and water was confirmed as physical hazard. Levels (Cd:0.01~0.103, Cu:0.001~6.036, As:0.006~3.045, Hg:ND~0.041, Pb:0.003~3.952, $Cr^{+6}$:0.007~0.496, Zn:0.001~66.500, Ni:0.003~18.010) of heavy metals in soil and water were appropriate for GAP criteria. In biological hazard, APC and coliform in soil were detected at the levels of $6.0{\pm}0.3$ and $3.6{\pm}1.6$ log CFU/g, and levels of water were $3.5{\pm}0.7$ and $1.9{\pm}0.7$ log CFU/mL, while E. coli wasn't detected in all sample. However, coliform in water wasn't appropriate for criteria, and E. coli O157 was detected about 22% in some farms, so it needs ways to prevent contamination by human and animals excrements. In conclusion, it needs proper management to prevent cross-contamination of hazards although physical and chemical hazard level were appropriate for GAP criteria while biological hazard wasn't.

• Journal of The Korean Society of Grassland and Forage Science
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• v.27 no.3
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• pp.189-196
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• 2007

This study was conducted to determine the effects of application levels of pig slurry on the characteristics of runoff water in volcanic ash soil in Jeju, Korea. This study was arranged in randomized complete block design. The data represent the means of the three experiments. Experimental plots were consisted of five treatments such as no fertilizer, chemical fertilizer at 200kg N/ha/year and pig slurry levels at 200, 400 and 600kg N/ha/year. The concentrations of BOD and COD in 600kg N/ha pig slurry were significantly higher (p<0.05) than those of the other treatments at initial sampling at 12 days after application. The total nitrogen concentration in runoff water increased with increasing pig slurry. The total phosphorous concentration in runoff water was hardly influenced by application levels of pig slurry since there were no significant difference among the treatments. The concentrations of $NO_3-N\;and\;NH_4-N$ were raised (p<0.05) in proportion to application levels of pig slurry. In conclusion, pig slurry usage at 200kg N/ha to the volcanic ash soil in Jeju area can replace the chemical fertilizer. However, more than 200kg N/ha of pig slurry may not be appropriate, because it may contaminate the water environment.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.spc
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• pp.57-61
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• 2009

To clarify the impact of the rice-duck farming system on the regional environment and the surrounding, a case study was carried out at Hongdong Reservoir valley of Hongdong-myeon and Janggok-myeon, Hongseong-gun, Chungcheongnam-do where the density of livestock grazing is the highest and rice cultivation with the rice-duck farming system is extensively practiced. The soil characteristics and water qualities at paddy fields were compared between two rice cultivation methods of rice-duck farming system and conventional farming system. The organic matters and available phosphate contents in soil of paddy fields where the rice-duck farming system was practiced were higher than those of paddy fields where conventional farming system was practiced. However, the available phosphate content was lower than the optimum for rice cultivation and the mean concentration of paddy soil in Korea. The surface water quality of the paddy field with the rice-duck farming system was practiced had higher EC (137 %), $COD_{Cr}$ (220 %), T-N (172 %), and T-P (226 %) contents than that with the conventional farming system was practiced. Especially, $COD_{Cr}$ and T-P were more than 2 times higher, which tells that the possibility of water pollution by drainage water of paddy field is higher in the paddy fields with the rice-duck farming system practiced than in those with the conventional farming practiced. The higher contents of T-P and $COD_{Cr}$ in surface water at the paddy field of rice-duck farming system practiced were directly caused by soil particles in the muddy water. Consequently, it is necessary to thoroughly manage the irrigation and drainage system of rice-duck farming system practiced to prevent outflow of surface water from paddy and pollution of surrounding water system.

• Journal of the Korea Convergence Society
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• v.9 no.7
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• pp.63-68
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• 2018

Research on smart farms centering on greenhouse cultivation is actively under way due to the decrease in agriculture population and aging, but in the case of vegetables such as vegetables, outdoor cultivation is 70%. Therefore, there is a need to improve productivity and prevent soil contamination by automating, cultivating, and intelligentizing the outdoor cultivation of agriculture crops. In this paper, we show the case of establishing a outdoor production system using the Internet of things and define the environmental variables in the outdoor production system. By measuring soil temperature, water content, electrical conductivity and acidity through sensors, LoRa communication module transmits the information to the outdoor production system. The outdoor production system controls the amount of fertilizer and the volume of water based on this sensor data. We have developed a system that manages a wide range of crops using LoRa technology, which is a suitable communication method for cultivating crops, and manages production volume and sales performance.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.11
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• pp.733-738
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• 2014

Within the scope that does not interfere with the performance of basic duty, the military has been actively supporting the national policy for the conservation of the natural environment in accordance with the "military environmental protection guidelines". Since there is a lack of information regarding inhabitation for wild fauna and flora, field investigations of the natural environment at Jinhae local unit were performed three times in 2003. As a result of the investigation, lycoris sanguinea as flora, marten, otter, and leopard cat as mammalia, and accipiter soloensis, accipiter gentilis schvedow, accipiter gularis, buteo hemilasius, falco tinnunculus and terpsiphone atrocaudata as bird were confirmed to inhabit. For the conservation of the natural ecosystem, the expansion of research for natural ecosystems within the military unit is required. Additionally, environmental pollution can be prevented through the proper maintenance of basic environmental facilities including sewage treatment facilities, soil pollution control facilities, and waste storage facilities. In cooperation with local governments and private organizations, the natural cleansing action and sustainable wildlife conservation should be expanded.

• Journal of Soil and Groundwater Environment
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• v.12 no.1
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• pp.87-96
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• 2007

Risk assessment was carried out in order to improve the remediation and management strategy on a contaminated gunnery site, where a flood control reservoir is under construction nearby. Six chemicals, including explosive chemicals and heavy metals, which were suspected to possess risk to humans by leaching events from the site were the target pollutants for the assessment. A site-specific conceptual site model was constructed based on effective, reasonable exposure pathways to avoid any overestimation of the risk. Also, conservative default values were adapted to prevent underestimation of the risk when site-specific values were not available. The risks of the six contaminants were calculated by API's Decision Support System for Exposure and Risk Assessment with several assumptions. In the crater-formed-area(Ac), the non-carcinogenic risks(i.e., HI values) of TNT(Tri-Nitro-Toluene) and Cd were slightly larger than 1, and for RDX(Royal Demolition Explosives), over 50. The total non-carcinogenic risk of the whole gunnery range calculated to a significantly high value of 62.5. Carcinogenicity of Cd was estimated to be about $10^{-3}$, while that of Pb was about $5\;{\times}\;10^{-4}$, which greatly exceeded the generally acceptable carcinogenic risk level of $10^{-4}{\sim}10^{-6}$. The risk assessment results suggest that an immediate remediation practice for both carcinogens and non-carcinogens are required before the reservoir construction. However, for more accurate risk assessment, more specific estimations on condition shifts due to the construction of the reservoir are required, and more over, the effects of the pollutants to the ecosystem is also necessary to be evaluated.

• Korean Journal of Environmental Agriculture
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• v.24 no.2
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• pp.191-197
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• 2005

Green house soils have been intensively cultivated with excessive application of compost and chemical fertilizer for vegetable growth. The objective of this study was to establish the reasonable fertilizer application system for rice cultivation in green house soil. Field experiment was carried out with rice cv. Geumo-byeo 1 in Jisan series soil (fine loamy, mixed, mesic family of Fluventic Haplaquepts) that was previously cropped with green pepper (Capsicum annuum L.) for the last 3 years. Treatment consisted of conventional fertilization $(N-P_2O_5-K_2O=11-4.5-5.7kg\;10a^{-1})$, no basal fertilization, 50% reduction of basal fertilization no top dressing, bulk blending fertilizer, and no fertilizer. The value of pH, available phosphate, and exchangeable potassium after experiment was lower than those before experiment while organic matter content was not difference in all treatment. The value of salt elusion was the highest in no basal fertilization plot. The amount of $NH_4-N$ in soil was higher in growth stage of rice as fertilizer amount increased in 1998. The changes of plant height and tiller were higher as fertilizer amount increased. Thousand-grain weight as yield component was higher in no basal fertilization plot all the year because of decreasing panicle. There was no significant difference in rice yield between treatments in 1998. However, conventional fertilization resulted in significantly increased rice yield in 1999. Nitrogen use efficiency was the highest in no basal fertilization plot in 1998 and in conventional fertilization plot in 1998. Our results suggest that no basal fertilization be best to increase salt elusion with slightly increased yield in first year for rice cropping after vegetable harvesting, which method improves fertilization efficiency. However, conventional fertilization was good for second rice cropping after vegetable harvesting in greenhouse.