• 한국지하수토양환경학회지:지하수토양환경
• /
• 제16권5호
• /
• pp.53-66
• /
• 2011

Groundwater which infiltrated in recharge areas discharges in the forms of evapotranspiration, baseflow to streams, groundwater abstraction and eventually flows into the sea. This study characterized radon-222 concentration and electrical conductivity (EC) in coastal groundwater discharge, well groundwater, Ilkwang Stream water, and seawater in the coastal area of Busan Metropolitan City and subsequently estimated groundwater discharge rate to the sea. The median value of Rn-222 concentration is highest in well groundwater (18.36 Bq/L), and then decreases in the order of coastal groundwater discharge (15.92 Bq/L), Ilkwang Stream water (1.408 Bq/L), and seawater (0.030 Bq/L). The relationship between Rn-222 concentration and EC values is relatively strong in well groundwater and then in seawater. However, the relationship is not visible between coastal groundwater discharge and Ilkwang Stream water. The groundwater discharge rate to the sea is estimated as $3,130m^3$/day by using radon mass budget model and $16,788m^3$/day by using Darcy's law.

• 한국유기농업학회지
• /
• 제18권1호
• /
• pp.83-92
• /
• 2010

미나리 유기재배 방법을 설정하기 위해 관행 재배구를 대조구로 하고 유용미생물제(effective microorganism), 액상규산염(silicate solution), 및 유기액상비료(organic liquid fertilizer)를 사용하여 재배하였다. 미나리 수확기에 조사한 토양 pH, EC, OM, 유효인산, 치환성 칼슘, 유효규산함량은 수확기에 감소하였고, 치환성칼륨과 마그네슘은 1, 2년차에는 수확기에 감소하였지만, 3년차에는 증가하였다. 대조구에 비해 액상규산염을 사용할 경우 pH, 유기물, 유효인산함량이 감소하였고, 유용미생물제는 치환성 Ca과 Mg, 유기액상비료는 EC와 치환성 Ca과 K가 감소하였다. 미나리에 함유되어 있는 다량원소 가운데 C, N, P, K, 및 S는 대조구보다 함유량이 많았고, Ca과 Mg은 대조구와 비슷하였다. 담배거세미나방과 역병은 모든 처리구에서 비슷한 수준으로 나타났고, 점무늬병은 대조구에서 나타났다. 생육시기별로 처리간에 엽록소 함량 차이는 없었지만, 액상규산염을 사용한 구의 초장은 60.2 cm, 수량 3,698 kg/10a로 가장 적었고, 유기액상비료를 사용한 경우 66.0 cm와 4,387 kg/10a로 가장 많았다.

• 생물환경조절학회지
• /
• 제15권1호
• /
• pp.35-46
• /
• 2006

Objective of this research was to determine the effect of application rate of a slow release fertilizer (SRF) in three root media, peatmoss+vermiculite (1:1, v/v; PV), peatmoss+composted rice hall (1:1, v/v; PR), and peatmoss+composted pine bark (1:1, v/v; PB), on growth and nutrient contents of potted chrysanthemum 'Lima Honey'. All media contained polyacrylic acid sodium salt at a rate of $4.5g L^{-1}$. The fresh and dry weights at 43 days after transplanting did not show statistical differences among treatments in each root media. Elevated application rate of SRF increased fresh and dry weights at 80 days after transplanting in PV and PB media, but not in PR medium. Elevated application rates of SRF resulted in the increase of tissue phosphorus content and decrease of tissue Ca, Na, and Zn contents at both 43 and 80 days after transplanting. Elevated application rates of SRF resulted in the decrease of pH and increase of EC and concentrations of ${NO_3}^-$ and ${P_2O_5}^{3-}$, K, Ca, and Mg in the soil solution of PV and PR media. The trends of those in PR media were also similar except ${NO_3}^-$. The differences among treatments in EC at 80 days after transplanting were less significant as compared to those at 43 days after transplanting in three media.

• 원예과학기술지
• /
• 제29권3호
• /
• pp.201-210
• /
• 2011

This experiment was conducted to investigate physical and chemical characteristics by volume fractions of root media using peatmoss, perlite, and vermiculite, along with effects on the growth of pot chrysanthemums (Dendranthema ${\times}$ grandiflorum 'Vemini') in a C-channel mat irrigation system. To evaluate the physico-chemical properties of 20 root media, the bulk density, particle density, total pore space, pore space, ash content, organic matter, pH, and electrical conductivity were measured and data were analyzed using principal component analysis (PCA). PCA scores revealed that physico-chemical properties changed by the blending of peatmoss, perlite, and vermiculite. The 20 root media were divided into three main groups by hierarchical cluster analysis. At the end of the experiment, the pH and EC of the root media were measured from media divided into four layers. The pH of root media without plants showed a strong linear relationship and the pH of root media with plants increased exponentially. The change of EC in the root medium was indicated as a hyperbolic curve. Plant growth characteristics according to growth in the 20 root media were analyzed by PCA. It was found that the mixing ratios of the root media affected plant growth characteristics. Therefore, mixing ratio is an important factor for pot-plant production in a subirrigation system.

• 한국약용작물학회지
• /
• 제23권5호
• /
• pp.351-356
• /
• 2015

Background : Ginseng is mainly grown as a break crop in paddy fields after rice has been cultured for approximately 4 - 5 years, because it reduces the negative effects of continuous rice cropping. However, physiological disorders, such as leaf discoloration, occur in ginseng grown in paddy fields with poor drainage and excessive levels of inorganic components. Methods and Results : This study investigated the effect of ridge height on the growth characteristics and yield of 6 year old Panax ginseng. Ridge height was varied by making 20, 30, and 40 cm high ridges in a pooly drained paddy field. Soil moisture content decreased, while electrical conductivity (EC) as the ridge height increased. The $NO_3$, K, Ca, Mg, and Na levels also rose as ridge height increased, but organic matter and $P_2O_4$ levels did not. The leaf discoloration ratio rose as the ridge height increased, and root yield reached a peak when the ridge height was 30 cm. Conclusion : A ridge height of 30 cm in poorly drained paddy field improved ginseng growth by reducing leaf discoloration and increasing root survival, owing to more suitable soil moisture and EC levels.

• 한국토양비료학회지
• /
• 제49권5호
• /
• pp.572-576
• /
• 2016

Soil quality assessment is an important tool for environmental management in an agricultural field. It can be used to evaluate the health of the soils and to establish the basis for sustainable urban agriculture and soil management. For this study, the chemical properties of the soils used for urban agriculture were examined. Results of the soil analysis for chemical properties were applied to soil quality assessment system, which is composed of principal component analysis, application to scoring function and derivation of soil quality index (SQI). Soil pH, electrical conductivity (EC), organic matter (OM), total nitrogen (T-N) were determined for minimum data set (MDS) according to principal component analysis. Based on the results of scoring for four indicators (pH, EC, OM, T-N), soil pH was the indicator that needs the most urgent management. Results of SQI derivation showed that many of the urban farms appeared to be insufficient score in comprehensive soil quality assessment. In conclusion, soil management practices based on scores derived from soil chemical indicators need to be carried out to maintain sustainable urban agricultural soil environment and to provide easy-to-understand information to urban farmers.

• 한국유기농업학회지
• /
• 제22권4호
• /
• pp.683-693
• /
• 2014

폐자원인 우렁쉥이 껍질을 이용한 환경친화형 유기농 액비의 개발을 위하여 유용미생물(EM)을 이용한 우렁쉥이 껍질의 최적 발효조건과 액비의 특성을 조사한 결과 다음과 같다. EM발효 우렁쉥이 껍질 액비 제조 시 당밀의 투입량이 증가할수록 pH는 낮아지며, EC는 높아지는 것으로 나타났으며, pH는 당밀이 10% 이상 투입된 시험구에서 일정하게 유지되었다. EM발효 우렁쉥이 액비의 총 질소 함량은 발효가 경과할수록 현저히 증가하였으며, 특히 당밀이 15% 이상 투입된 시험구에서 약 220% 증가율을 나타내었다. 인의 함량은 발효 21일차에서 최고치를 나타내었으며, 칼륨의 함량은 발효가 경과할수록 증가하였다. 칼슘, 마그네슘, 나트륨의 함량 역시 발효가 경과할수록 증가하였고 당밀이 15% 이상 투입된 시험구에서 증가율이 우수한 것으로 나타났으며, 칼슘의 함량이 상대적으로 높은 것으로 나타났다. 유해성분(As, Cd, Cu, Cr, Hg, Ni, pb 및 Zn)의 함량은 시험구 모두에서 비료공정규격 기준치에 적합하였다. 우렁쉥이 껍질 액비의 유리아미노산은 총 29종이 검출되었으며 총량은 7,080.94 mg/L를 나타내었고 알라닌이 656.32 mg/L로 가장 높은 함량을 나타내었다. 이상의 결과를 미루어 볼 때 우렁쉥이 껍질을 이용한 액비화에는 당밀이 15% 이상 투입된 조건이 최적인 것으로 판단된다.

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제17권4호
• /
• pp.51-62
• /
• 2012

Effects of climate change on groundwater system requires understanding the groundwater system in temporal and spatial scales through the long-term monitoring. In this study, the spatio-temporal variations of groundwater were analyzed through the continuous observation of water level, electrical conductivity (EC) and water temperature with automatic data-loggers and sampling in a Gwangneung catchment, Korea, for the four years from 2008 to 2011. Groundwater monitoring were performed at the nest-type wells, MW1 and MW2, located in upsteam and downstream of the catchment, respectively. During the survey period, both the total amount of annual precipitation and the frequency of concentrated rainfall have increased resulting in the elevation of runoff. Water level of MW1 showed no significant fluctuations even during the rainy season, indicating the confined groundwater system. In contrast, that of MW2 showed clear seasonal changes, indicating the unconfined system. The lag-time of temperature at both wells ranged from one to three months depending on the screened depths. Results of chemical analyses indicated that major water compositions were maintained constantly, except for the EC decreases due to the dilution effect. Values of the stable-isotope ratios for oxygen and deuterium were higher at MW2 than MW1, implying the confined system at the upstream area could be locally developed.

• 한국식품저장유통학회지
• /
• 제31권4호
• /
• pp.554-564
• /
• 2024

The effects of extracting solvents on the physicochemical properties of vegetable oils extracted from four oil seed plants, namely Dennettia tripetala, Dacryodes edulis, Cola rostrata, and Persea americana, were studied. Vegetable oils were extracted using the Soxhlet method. The oils were used for determining % yield, acid value (AV), iodine value (IV), saponification value (SV), electrical conductivity (EC), and pH. The results revealed that the range of the mean % yield of oils extracted using hexane, carbon tetrachloride (CCl₄), petroleum ether, acetone, and methanol, respectively, were 7.5-12.0, 9.0-22.0, 7.5-27.5 and 12.0-37.5 for the four oil Seeds respectively. Mean AVs of oils in mg KOH/g across the solvents were 3.1-3.7, 3.1-3.8, 2.5-3.9 and 2.4-2.8 for Cola rostrata, Dacryodes edulis, Dennettia tripetala and Persea americana respectively. Mean IVs of oils in gI2/100 g across the solvents were 33.25-33.97, 33.06-33.35, 32.06-33.76 and 33.00-34.00 for the four oil seeds, respectively. Mean SVs in mg KOH/g across the solvents were 191.00-197.44, 190.74-198.31, 194.11-202.52, and 182.23-199.44, respectively. Mean EC values ranged 0.31-0.32, 0.30-0.33, 0.30-0.33, and 0.31-0.32 µS/cm across the solvents, respectively. Mean pH values ranged from 6.1-6.4, 4.6-6.3, 6.2-6.4, and 6.1-6.3 across the solvents for the oils, respectively. The AVs of the oils suggest that they are edible oils, the IVs classify the oils as non-drying oils suitable for paint making, and SVs reveal that the oils are good for soap making. Hexane, petroleum ether, and CCl4 are suitable for oil extraction industrially, while D. edulis, D. tripetala, and P. Americana oils are economically viable oil resources due to their high percentage yield, SV and IV.

• 지질공학
• /
• 제29권4호
• /
• pp.495-508
• /
• 2019

원주지역 지하수의 수리지화학 및 자연방사성물질인 우라늄과 라돈의 산출특성을 규명하기 위하여 40개 관정을 대상으로 시료를 채취하고 분석하였다. 연구지역 지하수의 EC는 최소 73에서 최대 400 μS/cm (평균 212 μS/cm)의 범위를 나타내고 있으며, EC의 증가와 더불어 주요 용존 양이온과 음이온의 함량도 증가하는 경향을 나타낸다. 우라늄 농도는 0.06~50.5 ㎍/L (중앙값 1.55 ㎍/L)로 넓은 분포를 보여주고 있으며, 라돈은 67~8,410 pCi/L (중앙값 1,915 pCi/L)의 범위를 나타내고 있다. 우라늄 농도에서 미국 EPA MCL 30 ㎍/L를 초과한 곳은 3개소로 전체 시료수의 7.5%에 해당된다. 라돈의 경우, 미국 EPA AMCL(Alternative Mximum Contaminant Level) 4,000 pCi/L를 초과한 곳은 9개소로 전체 시료수의 22.5%이다. 이중 핀란드의 음용 제안치인 8,100 pCi/L를 초과하는 시료는 1개소이다. 연구지역에서 지질별 지하수의 우라늄과 라돈 농도는 흑운모화강암 지역의 지하수에서 가장 높다. 연구지역 지하수의 우라늄과 라돈 함량은 유사한 지질을 가지는 외국에 비하면 낮은 것으로 나타났다. 이는 우리나라 지하수 관정의 특성상 케이싱 및 그라우팅이 미비한 관정이 많으므로 천부 지하수의 공내 유입을 의심할 수 있다. 이러한 관정의 특성으로 인하여 실제 함량보다 낮게 검출되었을 가능성을 배제할 수 없다.