• 한국토양비료학회지
• /
• 제25권1호
• /
• pp.57-61
• /
• 1992

질소염(窒素鹽)들의($(NH_4)_2SO_4$, $NH_4NO_3$, $KNO_3$, $Mg(NO_3)_2$, $Ca(NO_3)_2$, $(NH_2)_2CO$) 농도별(濃度別) 염강도(鹽强度)를 비교하고 영양액연속유출경사사경재배장치(營養液連續流出傾斜砂耕栽培裝置)를 이용하여 배추와 상치에 대한 발아장해정도(發芽障害程度)를 조사하였다. 그람분자량으로 동일농도(同一濃度)의 EC(electrical conductivity, mS/cm)를 측정한 결과 황산암몬은 1가염(價鹽)의 2배수준(倍水準)을 나타냈으나 질산고토, 질산석회는 1.5배정도 이었고 요소(尿素)는 전연 측정되지 않았다. 그리고 동일백분률(同一百分率) 농도(濃度)에서는 황산암몬(1.37)>질산암몬(1.22)>질산칼리(1.0)>질산석회(0.72)>질산고토(0.64)의 순(順)으로 EC치의 비율을 보였다. 배추와 상치의 발아에 가장 심한 장해를 주는 염(鹽)은 질산고토, 황산암몬이었으며 질산암몬도 질산칼리에 비하여 장해정도가 컸고 요소(尿素)는 질산칼리, 질산석회와 같이 가장 낮은 영향을 주었으나 농도가 짙어지면서 질산칼리, 질산석회도 장해를 나타냈다. 그리고 상치가 배추보다 발아장해에 더 예민한 편이었다. 발아장해(發芽障害)는 염농도(鹽濃度)보다 질소염(窒素鹽)의 종류(種類)에 더 큰 영향을 받는 것으로 나타났다.

• 한국환경과학회지
• /
• 제20권11호
• /
• pp.1447-1455
• /
• 2011

The purpose of this study was to analyze physicochmical characteristics of oil within planting base of Incheon coastal reclamation cities where 10 years have passed since reclamation, and to provide basic data to promote growth and development of plants by conducting evaluation based on the planting degree standard. Study targets were Cheongra, Sondo, and Yeongjong districts within Incheon Free Economic Zone, the coastal reclamation city. The analysis results of average soil characteristics of 3 districts. Soil acidity(pH) was shown in orders of Cheongra district(8.85) > Songdo district(8.70) > Yeongjong district(7.97) and electric conductivity(EC) was shown in orders of Cheongra district(4.80 dS/m) > Songdo district(1.30dS/m) > and Yeongjong district(0.07 dS/m). Organic matter content(OMC) was shown in orders of Cheongra district(5.72%) > Songdo district(2.60%) > Yeongjong district(0.59%) and available phosphate was shown in orders of Cheongra district(70.70 mg/kg) > Songdo district(23.07 mg/kg) > Yeongjong district(2.49 mg/kg). $K^+$ was shown in orders of Songdo district(0.84 cmol/kg) > Cheongra district(0.74 cmol/kg) > Yeongjong district(0.22 cmol/kg), $Ca^{++}$ was shown in orders of Cheongra district(22.08 cmol/kg) > Songdo district(9.87 cmol/kg) > Yeongjong district(4.04 cmol/kg), and $Mg^{++}$ was shown in orders of Cheongra district(1.98 cmol/kg) > Songdo district(1.22 cmol/kg) > Yeongjong district(1.12 cmol/kg). Planting base level of coastal reclaimed land can be applied with above intermediate level, soil acidity and available phosphate were all more than intermediate in 3 districts, and electric conductivity was low level in Cheongra district and more than intermediate level in Songdo and Yeongjong districts. Organic matters content was more than intermediate level in Cheongra district and low level in Songdo and Yeongjong district. $K^+$ among exchangeable ions was intermediate level in Cheongra and Songdo districut and low in Yeongjong district. $Ca^{++}$ and $Mg^{++}$ both were more than imtermidiate levels in 3 districts.

• 한국환경농학회지
• /
• 제33권4호
• /
• pp.314-320
• /
• 2014

BACKGROUND: Run off from agricultural sites contaminates water bodies with nitrogen which is toxic and causes eutrophication when excessively accumulated. Hence, the interest in monitoring nitrogen toxicity in aquatic environment has been continuously increasing. METHODS AND RESULTS: To detect a real time toxicity of various nitrogen compounds, we applied biomonitoring method (biosensor) based on sulfur-oxidizing bacteria (SOB). The toxicity biomonitoring test was conducted in semi-continuous mode in a reactor filled with sulfur particles (2~4 mm diameter) under aerobic condition. Relative toxicity was simply determined by measuring the change in electrical conductivity (EC). Various nitrogenous compounds at different concentrations were evaluated as a potential toxic substance. Nitrite was found to be very toxic to SOB with a 90% inhibition even when the concentration as low as 3 mg/L. However, nitrate and ammonia have any inhibitory effect on SOB's activity. CONCLUSION: The biosensor based on SOB responded sensitively to nitrite even at substantially low concentrations. Therefore, it can be used as a reliable biological alarm system for rapid detection of contaminants due to its simplicity and sensitive nature.

• Journal of Biosystems Engineering
• /
• 제34권5호
• /
• pp.382-389
• /
• 2009

An in-situ probe-based spectrophotometer has been developed. This system used two spectrometers to measure soil reflectance spectra from 450 nm to 2200 nm. It collects soil electrical conductivity (EC) and insertion force measurements in addition to the optical data. Six fields in Kansas were mapped with the VIS-NIR (visible-near infrared) probe module and sampled for calibration and validation. Results showed that VIS-NIR correlated well with carbon in all six fields, with RPD (the ratio of standard deviation to root mean square error of prediction) of 1.8 or better, RMSE of 0.14 to 0.22%, and $R^2$ of 0.69 to 0.89. From the investigation of carbon variability within the soil profile and by tillage practice, the 0-5 cm depth in a no-till field contained significantly higher levels of carbon than any other locations. Using the selected calibration model with the soil NIR probe data, a soil profile map of estimated carbon was produced, and it was found that estimated carbon values are highly correlated to the lab values. The array of sensors (VIS-NIR, electrical conductivity, insertion force) used in the probe allowed estimating bulk density, and three of the six fields were satisfactory. The VIS-NIR probe also showed the obtained spectra data were well correlated with nitrogen for all fields with RPD scores of 1.84 or better and coefficient of determination ($R^2$) of 0.7 or higher.

• 한국환경과학회지
• /
• 제29권4호
• /
• pp.395-402
• /
• 2020

This study was conducted to analyze seasonal variations of de-icing salt ions harvested from soils and plants according to salt damage of Pinus densiflora f. multicaulis, a evergreen conifer, on roadsides. Pinus densiflora f. multicaulis was divided into three groups referred to SD, ND, and WD (serious salt damage (SD) = 71-100%, normal salt damage (ND) = 31-70%, and weak salt damage (WD) = 0-30%) based on the degree of visible foliage damage, and measured acidity (pH), electrical conductivity(EC), and de-icing salt ions (K⁺, Ca²⁺, Na⁺, and Mg²⁺) harvested from soils and plants. The results indicated that acidity, electrical conductivity, and de-icing salt ions of soils and plants were significantly affected by seasonal variation and salt damage. In addition, a strong positive liner relationship was observed in plants between the concentration of de-icing salts and salt damage in spring, while the relationship among seasonal variation and salt damage in soil were not significant. The results from this study has important implications for the management of conifer species in relation to salinity and roadsides maintenance.

• 상하수도학회지
• /
• 제25권6호
• /
• pp.949-957
• /
• 2011

This aim of study was to investigate the characteristics of discharge of pollutants as well as the correlation between flow rate and water quality constituents in a combined sewer system according to the characteristics of rainfall. For the loading rates for each pollutant, the median concentrations of all pollutants except T-N was increased when a CSO took place. The loading rates of BOD, COD, SS, T-N, T-P, Cu and Zn at the CSOs were 328-1255, 25-129, 83-2009, 4-12, 14-51, 5-11 and 5-13 times higher than the DWF (Dry Whether Flow), respectively. Especially, SS loading rate was found to be highest in all pollutants. On the other hand, the range of the first flush coefficient, b for water quality constituents such as BOD, COD, SS, T-N, T-P, Cu and Zn were 0.537-0.878, 0.589-0.888, 0.516-1.062, 0.852-1.031, 0.649-0.954, 0.975-1.015 and 0.900-1.114, respectively. In term of correlation between flow rate and pollutant concentrations, SS concentration was highly correlated to flow rate. However, there was an inverse correlation between EC (Electrical Conductivity) and flow rate because of the high dilution of flow rate. In case of correlation between pollutants, there was a high correlation between SS and T-P.

• 한국토양비료학회지
• /
• 제44권3호
• /
• pp.510-516
• /
• 2011

Salt-affected soils are present in Pakistan in significant quantity. This experiment was conducted to assess the effectiveness of compost for reclamation and compare its efficiency with gypsum. For this purpose, various combinations of compost and gypsum were used to evaluate their efficacy for reclamation. A saline-sodic field having $pH_s$ 8.90, $EC_e$ $5.94dS\;m^{-1}$ and SAR $34.5(mmol\;L^{-1})^{1/2}$, SP (saturation percentage) 42.29% and texture Sandy clay loam, gypsum requirement (GR) $8.75Mg\;ha^{-1}$ was selected for this study. The experiment comprised of seven treatments (control, gypsum alone, compost alone and different combinations of compost and gypsum based on soil gypsum requirements). Inorganic and organic amendments (gypsum and compost) were applied to a saline sodic soil. Rice and wheat crops were grown. Soil samples were collected from each treatment after the harvest of both crops and analyzed for chemical properties (electrical conductivity, soil reaction and sodium adsorption ratio) and fertility status (organic matter, available phosphorus and potassium contents) of soil. Results of this study revealed that compost and gypsum improved chemical properties (electrical conductivity, soil reaction and sodium adsorption ratio) of saline sodic soil to the desired levels. Similarly, all parameters of soil fertility like organic matter, available phosphorus and potassium contents were built up with the application of compost and gypsum.

• 한국기계가공학회지
• /
• 제20권2호
• /
• pp.8-13
• /
• 2021

The study for soil has been conducted separately by several areas such as soil mechanics and soil chemistry. Soil is important in terms of prediction of how the plant grow with nutrient requirement. Also, soil is important for machines to work on to solve labor shortage and save farmers from harsh environment during farm work. To meet diverse needs related to soil in agriculture, the soil related study needs to be conducted synthetically. Thus, we tried to obtain the data related to soil chemistry including pH and Electrical Conductivity (EC) with data related to soil mechanics including Cone Index (CI), moisture content, soil classification. Specifically, the condition of the field was set to be cultivated at least for five years continuously at a first step. The soil was taken from 30 sites. CI was obtained using the soil penetrometer and soil classification was conducted using sieve analysis with eight kinds of sieve. The soil was taken on December when is during winter in Korea. There was variation of data including moisture content and CI.

• 한국환경농학회지
• /
• 제25권1호
• /
• pp.64-70
• /
• 2006

토양의 양분을 고려하지 않고 관비재배 하는 경우는 토양에 양분 과다집적, 지하수 오염 및 작물생산성에 영향을 미칠 수 있다. 토마토 재배시 토양 양분 함량에 따른 최적 관비농도를 알아보고자 토양의 EC 수준에 따라 관비공급 농도를 4 수준으로 처리하여 토양 환경변화와 토마토의 수량을 평가한 결과는 다음과 같다. EC 수준이 1.4, 3.0 및 5.4 dS/m인 토양에 관비농도를 0(groundwater), 1.0, 2.0 및 3.0 dS/m으로 공급하여 토마토를 관비재배 하였을 때 1과중, 상품율 및 상품수량은 처리간에 유의성이 없는 것으로 나타났다. 따라서 적정 수량을 유지하고 토양내 양분집적이 일어나지 않도록 관비하는 것이 가장 좋은 관비방법이라 생각된다. 토양의 EC가 1.4 및 3.0 dS/m인 조건에서 관비 농도를 3.0 dS/m으로 공급한 경우 수확후 토양의 EC는 각각 1.8 및 5.0 dS/m로 생육초기 보다 크게 증가하였고, $NO_3-N,\;P_2O_5$ 및 K등의 양분이 집적 되었다. 따라서 3.0 dS/m 미만으로 관비를 공급하는 것이 토마토의 적정 수량과 토양관리에 바람직할 것으로 생각되었다. 토양의 EC가 5.4 dS/m인 조건에서 관비공급 농도 1.0 dS/m이상은 $NO_3-N,\;P_2O_5$ 및 K등의 양분이 집적되었으며 지하수만 공급하여도 정상적인 수량을 생산할 수 있었다. 토마토 엽의 무기성분 함량은 토양 EC 수준과 관계없이 관비공급 농도를 높였을 때 T-N, $P_2O_5$ 및 $K_2O$ 함량이 증가하였고, CaO와 MgO 함량은 감소하였다.

• 생물환경조절학회지
• /
• 제23권2호
• /
• pp.144-147
• /
• 2014

감자 가공용 신품종'새봉'의 무병주 대량생산을 위하여 microponic system에서 배양액의 농도변화가 감자 소식물체 생육에 미치는 영향을 구명하고자 수행 하였다. 조절한 감자 배양액의 농도는 EC 0.2, 0.6, 1.0, 1.4, 1.8, $14.0dS{\cdot}^{-1}$수준 이었으며 감자 조직배양묘는 생장점과 잎을 2개 포함한 1.5cm길이로 잘라 50mL 유리병(glass vial)에 1개씩 치상하여 18일, 또는 21일간 2회에 걸쳐 하였다. 배양액 량은 용기 당 2mL씩 넣고 10일 후 1 mL를 첨가하였으며, 환경조건은 일장 16시간, 온도 $23{\pm}1^{\circ}C$, $40mmol^{-2}{\cdot}s^{-1}$의 백색 LED에서 실험 I의 배양액농도는 EC 0.2, 1.0, $14dS{\cdot}m^{-1}$였으며, 실험 II의 배양액농도는 0.6, 1.0, 1.4, $1.8dS{\cdot}m^{-1}$로 조정하였다. 치상 7일 후 소식물체의 생존율은 $0.2dS{\cdot}m^{-1}$에서 90%, $0.6dS{\cdot}m^{-1}$에서 100%, $1.0dS{\cdot}m^{-1}$에서 100%, $1.4dS{\cdot}m^{-1}$에서 0%, $1.8dS{\cdot}m^{-1}$에서 0%, $14.0dS{\cdot}m^{-1}$에서 0% 이었다. 배양액의 전기전도도를 $1.0dS{\cdot}m^{-1}$으로 조절한 처리에서 이식 2일 후 뿌리가 발육되어 소식물체 생육이 왕성하게 생장하여 18일 만에 7개의 엽, 길이 5cm, 생중 0.5g이상의 식물체로 생육하였다. 배양액의 농도를 $0.6dS{\cdot}m^{-1}$으로 조절한 처리에서는 이식 4일 후부터 뿌리가 발육되어 21일 후 5개의 엽, 길이 4cm, 생중 0.2g을 가진 식물체로 생육하였다. 따라서 microponic system에서 무병 감자 묘 대량생산을 위해서는 감자배양액의 전기전도도를 $0.6{\sim}1.0dS{\cdot}m^{-1}$ 조절하여 관리하는 것이 효과적임을 알 수 있었다.