• The Journal of Natural Sciences
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• v.9 no.1
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• pp.39-44
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• 1997

This study was aimed to observe the effects of municipal sewage sludge as nutrients on the growth of Lettuce. The effects of heavy metal components of the sludge were also observed. Municipal sewage sludge from Taejon City were treated to the soil of PaiChai University Farm in order to make gradient of nitrogen concentration in soil among 6 experimental groups. Results are as follows ;The longest leaves and roots were produced in control pot, in which urea was supplied as nitrogen source to the soil. Any other sludge-treated groups produced shorter leaves and roots than control group, but the more sewage sludge treated the longer leaves and heavier vegetables were observed. No differences were observed among from 6 experimental groups in the view of N, K, Ca and Mg contents. But P contents in leaves from 6 groups varied. Zn content of Lettuce when was 65.8 mg/kg when it grew with sludge 200%. The groups treated with sludge 200% produced the vegetables of highest Zn contents. Accumulation of Zn, Mn and Cd was more heavier in Lettuce than in Altari radish. Accumulation of Zn, Mn, Cu and Cd in lettuce was not heavier than natural contents of those in market vegetables.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.191-191
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• 2011

우리나라의 수질 관리는 점오염원 관리에 집중되어 왔다. 수계의 수질이 크게 향상되지 않는 이유는 점오염원의 관리가 엄격히 수행되고 있는 가운데 비점오염원의 영향이 큰 것으로 판단되었다. 본 연구에서는 수문수질 모의가 가능한 SWAT (Soil and Water Assessment Tool) 모형을 이용하여, 비점오염원 저감을 위한 BMP (Best Management Practice) 시나리오를 작성하여 비점오염 부하량의 저감효과를 모의하였다. SWAT 모형의 적용성 평가를 위해 충주댐 유역 ($6,585.1km^2$)을 대상으로 민감도 분석을 통해 최적의 유출 및 유사관련 매개 변수를 선정하였으며, 1998년 부터 2003년까지의 기간 동안 일별 유출, 월별 수질자료에 대한 보정 및 검증을 실시하였다. 전체 17개 소유역에 대한 검보정에 의해 산정된 수질자료인 TN (Total Nitrogen), TP (Total Phosphorus) 그리고 sediment의 부하량을 파악하여 소유역별 TN, TP, Sediment 오염부하특성을 파악하였고, 이에 대하여 선정한 7개의 BMP 시나리오를 소유역의 오염 특성에 맞게 적용하였다. 선정한 BMP 시나리오로는 Streambank stabilization, Porous gully plugs, Recharge structures, Conservation tillage, Terrace, Contour farming 그리고 Manure incorporation이 있고 각 시나리오는 흐름에서의 침전물 감소, 단기간의 토양침식 저감, 지하수양의 증가, 경작지의 침식감소, 지표유출 저하, 흐름에서의 영양물질 감소를 목적으로 최적의 매개변수를 설정하였다. 이상의 결과를 종합적으로 고찰해 볼 때 SWAT 모형은 실측자료를 바탕으로 비점오염에 의한 하천수질 모의가 가능하며, 이 결과를 가지고 BMP시나리오를 적용하여 비점오염 저감에 따른 하천수질 개선을 기대할 수 있다.

• Korean Journal of Microbiology
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• v.44 no.1
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• pp.63-68
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• 2008

Strain Kan-23 was extracted from nematophagous fungi, which were isolated from the soil sample of oriental melon field. The strain exhibited the slow-growing characteristic forming conidia after prolonged incubation for 30 days. Morphological features of strain Kan-23 were observed under scanning electron microscope (SEM). It possesses erect conidiophores which contain $2{\sim}3$ side branches, with each branch producing $5{\sim}10$ conidia. The size of conidiophores were between $160{\sim}450\;{\mu}m$. Conidia were ellipsoidal with three septa[septum] in each conidium. Strain Kan-23 captured nematodes by means of giant constricting rings, which were observed in the glucose peptone agar medium. ITS region of rDNA sequence was analyzed. On the basis of the high sequence similarity of ITS region (99%), the Kan-23 strain was closely related to Drechslerella brochopaga (U51950). This is the first report on Drechslerella brochopaga as a nematophagous fungus in Korea.

• Korean Journal of Environmental Agriculture
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• v.39 no.1
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• pp.44-49
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• 2020

BACKGROUND: Benzo(a)pyrene is a highly toxic substance which has been listed as a Group I carcinogen by the International Agency for Research on Cancer. There have been numerous studies by researchers worldwide on benzo(a)pyrene. Soxhlet, ultrasound-assisted, and liquid-liquid extractions have been widely used for the analysis of benzo(a)pyrene. However these extraction methods have significant drawbacks, such as long extraction time and large amount of solvent usage. To overcome these disadvantages, we aimed to establish a rapid residual analysis of benzo(a)pyrene content in agricultural products and soil samples. METHODS AND RESULTS: A Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method was used as the pretreatment procedure. For rapid residual analysis of benzo(a)pyrene, a modified QuEChERS method were used, and the best codition was demonstrated after various performing instrument analysis. The extraction efficiency of this method was also compared with Soxhlet extraction, the current benzo(a)pyrene extracting method. Although both methods showed high recovery rates, the rapid residual analysis method markedly reduced both the measurement time and solvent usage by approximately 97% and 96%, respectively. CONCLUSION: Based on these results, we suggest the rapid residual analysis method established through this study, faster and more efficient analysis of residual benzo(a)pyrene in major agricultural products such as rice, green and red chili peppers and also soil samples.

• Journal of Life Science
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• v.23 no.2
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• pp.242-248
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• 2013

The objective of this study was to develop a mineral phosphate-solubilizing bacterium as a biofertilizer. A mineral phosphate-solubilizing bacterium HR-1019 was isolated from cultivated soils. It was identified as Bacillus subtilis by 16S rDNA analysis. The phosphate-solubilizing activities of the HR-1019 strain against three types of insoluble phosphate, hydroxyapatite, tri-calcium phosphate, and aluminum phosphate were quantitatively determined. When 5% of glucose concentration was used as a carbon source, the strain showed marked mineral phosphate-solubilizing activity. Mineral phosphate solubilization was directly related to pH drop in the culture solution of the strain. The pathogenic activity and antifungal effects of the HR-1019 strain were measured inclear zones formed in PDA media.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.89-89
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• 2017

유기농업은 저농약, 무농약, 자연농법과 함께 환경 친화적 농업으로 인식되어 세계적으로 유기농산물 생산량 및 재배면적이 급격하게 증가하고 있다. 국내 역시 안전한 먹거리 생산과 재배환경에서의 유해물질 관리방안 구축 등이 필요한 상황이다. 자가생산 유기농자재, 가축분을 이용한 축분 퇴비와 액비, 그리고 유박 등이 유기농업에 활용되고 있으나 사용 유기농자재의 양분가용화와 양분이용효율에 따른 비점오염원 형태로 토양 및 수질에 미치는 환경영향 등의 관측과 분석이 필요한 실정이다. 따라서 본 연구의 목적은 밭 포장에서의 유기농업 적용에 따른 유기농과 관행농에서의 대표적 비점오염원인 영양물질(T-N 및 T-P)에 대한 원단위를 평가하는데 있다. 시험포장은 전북 순장군 순창읍에 위치하고 있으며, 유기질비료시비 및 관행작물(고구마)의 3반복 1처리구(경사도 $6.6^{\circ}$)와 관행농관리 및 관행작물(고구마)의 1반복 1대조구(경사도 $6.8^{\circ}$)로 구성하였다. 현장에서 강우량과 유량을 실측하였으며, 강우 이벤트 시 T-N 및 T-P의 수질항목을 샘플링 후 분석하였다. 2016년 현재까지 총 6회의 강우 이벤트가 발생하였으며, 그 중 4회의 수질 샘플링을 실시하였다. 유출률은 평균 유기농에서 32%와 관행농에서 57%로 나타났다. 이는 토지피복 및 선행강우 등의 영향으로 다양한 분포를 보여주었다. 유기농 처리구에서 수질 부하량이 전체적으로 높게 나타났으며, T-N의 경우 4.4배와 T-P의 경우 1.8배로 나타났다. 이러한 경향은 유출수의 농도 영향보다 유출량의 영향이 큰 것으로 보인다. 유기농 처리구의 경우 제초제 등의 농작업이 제대로 이루어지지 않아 조도계수가 높았으며, 유기농 처리구에서 유출량이 31% 수준으로 상대적으로 낮게 나타났다. 본 연구의 경우 관행적으로 이루어지는 제초관리 형태를 벗어난 경우로 일반적인 결론 도출에는 한계가 있으나 유기농업 경작지에서 일반적으로 식생분포가 활발한 특성을 보여주고 있다. 향후 추가적인 모니터링 연구가 지속적으로 필요하며, 본 연구를 바탕으로 유기농업 최적관리방안 제시에 필요한 기초자료로 활용되기를 기대된다.

• Journal of The Korean Society of Agricultural Engineers
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• v.63 no.1
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• pp.89-102
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• 2021

Soils in agricultural lands contain large amount of organic matter and nutrients due to the injected fertilizers and manure. During heavy rain, surface water and base runoff pollutants flows into a nearby stream or lake with eroded soil from agricultural lands. On the other hands, agricultural lands near the lake are inundated due to the increase of the water level in the lake, leading to organic matter and nutrient release from the inundated soil. In this study, releasing rates of nutrient salts and organic substances were analyzed for the soil in the agricultural land, where cultivation activities has been carried out and periodically flooded, to account for the possibility of contamination from the inundated agricultural land in reservoir areas The experiment results have shown that COD was released from the soil in anaerobic conditions, and T-P was released in both anaerobic and aerobic conditions. However, in the case of T-N, it was found that the runoff by soil was not made before the rainfall occurred, and when the soil was impound due to rainfall, the elution occurred under the aerobic conditions. Through the results of this study, it was possible to account for the effect of flooded agricultural lands on the water quality in the lake, and this could be reflected in an efficient agricultural non-point pollution management policy. In order to determine the precise releasing rate for each agricultural land, it is believed that the leaching experiment for paddy fields and grasslands are needed.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.284-284
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• 2021

비점오염원이란 도시, 도로 포장면, 무허가 가축시설, 무단 경작지 등의 불특정 장소에서 불특정하게 발생하는 오염원을 말한다. 이러한 비점오염원은 주로 강우특성(강수량, 강우강도, 강우지속시간 등)에 영향을 받는 특징을 가지고 있다. 강우시 비점오염원은 주로 불투수면적에서 오염물질이 주변 하천이나 호수에 유입되어 수생태계에 악영향을 미치게 된다. 비점오염원 중 도로 노면에서 발생하는 오염물질은 농지나 가축시설에서 발생하는 오염물질(부유물질 및 유기물) 등과 달리 주로 차량에서 발생하는 오염물질이 주를 이루고 있다. 강우시 토양의 수분포화가 충분히 이루어진 후 강우강도에 따라 유출이 발생하는 농경지와는 달리 도로 노면 유출수는 누적된 오염물질들이 강우시 한꺼번에 유출되기에 강우 초기 채수 간격을 짧게 하여 수질을 분석하는 것이 중요하다. 이에 본 연구에서는 강원도 횡성군을 관통하는 영동고속국도의 횡성휴게소 불투수 노면에서 발생하는 비점오염물질을 알아보기 위해 모니터링 후 수질분석으로 노면 유출수 성분을 알아보고, 오염부하량을 계산하여 유량가중평균농도(EMC, Event Mean Concentration)와 초기세척효과(Mass First Flush effect)을 산정하였다. 이후 타 토지이용에서의 유출 특성과 고속국도 휴게시설에서 발생하는 비점오염물질의 유출 특성에 대해 분석하였다. 추후 본 연구자료는 고속국도와 주변 편의시설 설계시 주변 수생태계에 미치는 영향에 대한 기초자료로 활용할 수 있을 것이다.

• Korean Journal of Soil Science and Fertilizer
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• v.24 no.4
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• pp.248-253
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• 1991

This study examines the effect of submergence on transformations of inorganic phosphorus and the relation between fractions of inorganic phosphorus and adsorbed phosphorus in Gangseo (paddy soil), Yesan (non-cultivated soil), and Jungdong soil (upland soil). The soils were submerged with glucose sol'n at $28^{\circ}C$ for 17 days. After, the soils were incubated with phosphate solution at $25^{\circ}C$ for 24 hours. The seguential fractionation of inorganic phosphorus and of iron were conducted to investigate transformations of them. Results obtained are as follows; 1. By submergence, Bray I-P were decreased from 53mgP/kg to 48mgP/kg in Gangseo, from 3mgP/kg to 1mgP/kg in Yesan, and from 120mgP/kg to 56mgP/kg in Jungdong soil. 2. $NH_4F$ extractable P was dominant fraction of adsorbed P. It was transformed into NaOH extractable P by submergence in Jungdong soil. 3. Dithionite-citrate-bicarbonate extractable iron (crystalline Fe) was transformed to oxalate extractable iron (amorphous Fe) by submergence in Yesan soil.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.5
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• pp.369-378
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• 2006

For precision farming the influences of site-specific N application on rice grain yield and quality were investigated in 0.5 ha paddy field from 2001 to 2003. In pre-cultured soil, EC, O.M., total nitrogen, phosphate and potassium content showed high spatial variation, ranging from 11.63 to 52.03% of coefficient of variation, while that of pH was relatively low. In rice growth characteristics, tiller number at panicle formation stage was more than 10% in coefficient of variation, but plant height, SPAD figure at panicle formation stage and milled rice yield, protein content in brown rice showed less below 10%. Spatial dependence was over 0.60 in pH, total nitrogen, phosphate and potassium in pre-cultured soil and was over 0.50 in plant height, SPAD figure and protein content, while it was below 0.22 in tiller number at panicle formation. The range of spatial dependence was longer than 20m in all factors except for protein content in brown rice. Basal dressing nitrogen rate was positively correlated with PH, $SiO_{2}$, plant height and SPAD figure. Nitrogen fertilization rate at panicle formation stage was positively correlated with EC and O.M.. Protein content in brown rice was positively correlated with $SiO_{2}$ in pre-cultured soil. Milled rice yield was positively correlated with plant height, tiller number and SPAD figure at panicle formation stage.