• 농약과학회지
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• 제20권2호
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• pp.159-164
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• 2016

꽈리허리노린재(Acanthocoris sordidus)는 흡즙성 해충으로서 가지과 작물을 주로 가해하며, 국내에서는 일부 고추농가에 피해를 주고 있다. 이러한 꽈리허리노린재를 방제하기 위하여 유기합성 살충제 20 종류와 7 종류의 친환경유기농자재를 이용하여 살충력을 알아보았다. 그 결과, 꽈리허리노린재 성충의 경우에는 약제처리 72시간이 경과한 후에 유기인계 살충제인 펜티온이 100%의 살충율을 나타내었고, 페니트로티온과 펜토에이트는 95% 이상의 살충률을 나타내었다. 3령 약충의 경우에는 펜티온과 페니트로티온, 펜토에이트가 72시간이 경과한 후에 100%의 살충력을 나타내었다. 반면에 친환경유기농자재의 경우에는 고삼추출물이 80% 함유된 약제를 처리한 결과 성충이 약제처리 72시간 후 53.3%의 살충력을 나타내었을 뿐 다른 약제들은 대부분 살충력이 없거나 저조하였다.

• 한국환경농학회지
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• 제38권4호
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• pp.338-351
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• 2019

우리나라에서 유역면적이 가장 큰 한강수계를 대상으로 충주댐 상류지역까지 시료채취 지점을 확대하여 지천과 본류 유역별 유입 기여도를 평가하고 일별 수문자료를 입수하여 시기별 잔류농약의 유출량의 계량화를 시도하였다. 채수장소는 남한강수계 19, 북한강수계 3, 경안천 1 및 팔당댐 아래로 모두 24지점이었는데, 남한강수계 채수지점은 본류의 충주댐 상류 3개소, 하류 3개소와 지천으로는 동강과 서강, 달천, 섬강 등 13개소였다. 시료채취는 2012년과 2014년에 4회씩 실시하였고 대상농약은 하천 농약잔류량 조사 시에 국내에서 검출된 바 있는 성분들을 포함하여 174 성분이었다. 밭농사용 농약으로는 diazinon, cadusafos, alachlor, metolachlor 및 dithiopyr 등이 검출되었고, 사용이 금지된 endosulfan sulfate도 검출되었다. Endosulfan sulfate의 검출은 주로 남한강 상류지역의 고랭지 경사지의 유출 때문이었고, diazinon의 경우는 고랭지 채소재배지 토양살충과 하류지역의 다양한 농업활동에 의한 것이라고 판단되었는데, 강우에 의하여 유출 농도와 양이 영향을 받는다고 사료되었다. 벼 재배용 농약은달천, 섬강을 포함하여 주로 하류지역에서 검출되었다. 검출된 농약은 살균제인 iprobenfos와 isoprothiolane, hexaconazole, 살충제 carbofuran, 제초제 oxadiazon이었는데 벼농사용 농약의 수계유출은 강우에 의한 것뿐 아니라 배수와 누수 등에 의해 재배기간 중에는 지속적으로 일어나는 것으로 판단되었다.

• Bulletin of the Korean Chemical Society
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• 제33권10호
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• pp.3311-3316
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• 2012

In this paper, a layered-carbon-$Fe_3O_4$ (LC-$Fe_3O_4$) hybrid material was synthesized through a facile one-pot solvothermal method and used as the adsorbent for the preconcentration of some phthalate esters (dimethyl phthalate, diethyl phthalate, diallyl phthalate, diisobutyl phthalate and benzyl butyl phthalate) in water samples. The effects of the adsorbent dosage, extraction time, the solution pH and salinity on the adsorption of the phthalate esters (PAEs) were investigated. The magnetic nanocomposite adsorbent could remove and enrich the PAEs from water samples efficiently. After the adsorption, the analytes were desorbed and then determined by high performance liquid chromatography-ultraviolet detection. Under the optimum conditions, the enrichment factors of the method for the analytes were in the range from 161 to 180. A linear response with peak area as the quantification signal was observed in the concentration range from 0.5 to $100ng\;mL^{-1}$. The limits of detection (S/N = 3) of the method were between 0.08 and $0.1ng\;mL^{-1}$. The method was suitable for the determination of trace phthalate esters in environmental water samples.

• 한국농공학회논문집
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• 제62권2호
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• pp.31-38
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• 2020

Controlled Low Strength Material (CLSM) has high fluidity and self-compaction characteristics. CLSM is mainly used for backfilling the excavated road. Early-age properties of CLSM should be characterized for fast restoration of the road. In this study, shear wave monitoring and Vicat needle test are performed to investigate the early-age properties of CLSM depending on the setting time. CLSM consists of CSA cement, fly ash, silt and sand, accelerator, and water. Five fly ashes with different chemical properties are used for CLSM samples. The penetration of CLSM along setting time is obtained through the Vicat needle test. A pair of bender elements are placed in a mold for shear wave measurement, and the change in shear waves with the setting time is monitored. The experimental results show that, regardless of the type of fly ash, the penetration depth decreases and the shear wave velocity increases with the setting time. Depending on the type of fly ash, initial and final times and shear wave velocity change. After testing, the correlation between penetration and shear wave velocity is obtained with high coefficient of determination. The shear wave measurement technique using the bender element can be used to identify early-age properties.

• 농업과학연구
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• 제48권3호
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• pp.589-596
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• 2021

Nitrogen applied to soil is highly prone to leaching and volatilization leading to gaseous emissions of nitrous oxide (N₂O) and ammonia (NH₃) which are of great environmental concern. Usage of biochar to reduce the discharge of nitrogen to the environment has attracted much interest in the recent past. Biochar is produced by pyrolyzing various biomasses under oxygen-limited conditions. Biochar is a carbonized material with high adsorptive powers for not only plant nutrients but also heavy metals. The objective of this study was to investigate the adsorption characteristics of NH₄-N onto biochar made from pine needles. The biochar was produced at various pyrolysis temperatures including 300, 400 and 500℃ and holding times of 30 and 120 minutes. The Langmuir isotherm was used to evaluate the adsorption test results. The chemical properties of the biochar varied with the pyrolysis conditions. In particular, the pH, EC and total carbon content increased with the increasing pyrolysis conditions. The rate of adsorption of NH₄-N by the biochar decreased with the increasing pyrolysis conditions. Of these conditions, biochar that was pyrolyzed at 300℃ for 30 minutes showed the highest adsorption rate of approximately 0.071 mg·g^-1. Thus, the use of biochar pyrolyzed at low temperatures with a short holding time can most efficiently reduce ammonia emissions from agricultural land.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2000년도 학술발표회 발표논문집
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• pp.431-437
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• 2000

The aim of the work described in this paper is to develope a pavement method for farm road. To this ends, a series of material test are conducted on in-situ soil which was mixed additives-coarse aggregate, polypropylene fiber, excellent soil compound etc. With the laboratory test results, in-situ pavement test was conducted during two years. The serious problem of the pavement is not appeared up to this time. And the measurement of field data is continued presently. The majority merits of this pavement method is low cost and using environmental materials.

• 농업과학연구
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• 제47권3호
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• pp.485-496
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• 2020

Recent changes in the disaster environment have greatly increased the possibility of internal erosion in deteriorated reservoirs; thus, countermeasure methods are required to enhance the drainage performance of embankments. Sand filters have been mainly used to prevent internal erosion; however, due to the sand depletion and environmental problems, new alternative materials are required to replace the sand in the filter zone. In this study, crushed stone was used instead of sand as a material that could satisfy permeability, material supply, demanding conditions, and economic efficiency. Although crushed stone has excellent drainage performance, it has a clogging phenomenon due to its high permeability. Accordingly, the materials need to be separated with a geotextile wrapping method. Additionally, the 3D numerical analysis and a large model experiment were conducted to evaluate the seepage characteristics and in-site application of the crushed stone filter. As a result, the crushed stone filter showed an excellent dispersion effect by reducing the pore water pressure by about 9.5 times that of the sand filter. In addition, it was shown that the safety factor for piping increased significantly by reducing internal erosion. When comparing the economics and supply and demand conditions of the material, crushed stone was evaluated as an effective method to reduce the internal erosion of embankments at deteriorated reservoirs.

• 한국환경농학회지
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• 제35권1호
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• pp.32-38
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• 2016

본 연구는 상승온도가 벼재배나 볏짚 및 요소 투입과의 복합작용을 통해 토양미생물에 미치는 영향에 대한 평가를 하였다. 상승온도에 의해 토양이화학성이 부분적으로 영향을 받았으며, 이러한 환경변화는 토양미생물에 간접적인 영향을 줄것으로 판단된다. 온도가 전체 토양미생물 밀도에 미치는 효과는 크지 않았으며, 방선균만 온도의 증가로 감소하였기 때문에 미생물 군집구성이 온도변화에 의해 부분적으로만 영향을 받았다는 것을 보여준다. 또한, 벼 재배에 의해 전체 PLFA 수치가 1.3배 증가하였다는 것은 식물이 토양미생물에 크게 영향을 미칠 수 있는 인자라는 것을 의미한다. 따라서 이러한 미생물 밀도 및 군집 변화가 물질순환이나 토양의 기능성에 미치는 영향에 대한 추가적인 검토가 필요할 것으로 생각된다.

• Journal of Microbiology and Biotechnology
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• 제25권12호
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• pp.2016-2023
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• 2015

Xylanase plays important roles in a broad range of industrial production as a biocatalyst, and its applications commonly require immobilization on supports to enhance its stability. Aluminum hydroxide, a carrier material with high surface area, has the advantages of simple and low-cost preparation and resistance to biodegradation, and can be potentially used as a proper support for xylanase immobilization. In this work, xylanase from Thermomyces lanuginosus was immobilized on two types of aluminum hydroxide particles (gibbsite and amorphous Al(OH)₃) through adsorption, and the properties of the adsorbed enzymes were studied. Both particles had considerable adsorptive capacity and affinity for xylanase. Xylanase retained 75% and 64% of the original catalytic activities after adsorption to gibbsite and amorphous Al(OH)₃. Both the adsorptions improved pH and thermal stability, lowered activation energy, and extended lifespan of the immobilized enzyme, as compared with the free enzyme. Xylanase adsorbed on gibbsite and amorphous Al(OH)₃ retained 71% and 64% of its initial activity, respectively, after being recycled five times. These results indicated that aluminum hydroxides served as good supports for xylanase immobilization. Therefore, the adsorption of xylanase on aluminum hydroxide particles has promising potential for practical production.

• 환경정책연구
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• 제3권1호
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• pp.95-117
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• 2004

This study was conducted to estimate nitrogen discharge from Korea (southern part of Korean peninsula) as NPS(non-point source) by mass balance approach; input and output analyses of nitrogen using existing data available. The material flow was sectored into three different activities; agricultural (raising crop and animals), human and natural activities in forest and urban areas. Atmospheric deposition, biological nitrogen fixation, inorganic fertilizers and manures applied, animal feed and imported foodstuffs such as crops, meat and fish were the inputs in this study, while ammonia volatilization, denitrification, human and animal waste generation, crop and meat production, and discharge into river to ocean were the outputs. The estimated total nitrogen input was $1,194.5{\times}10^3$ tons N/year and the river discharge was 408 to $422{\times}10^3$ tons N/year, of which 66 to 71% was from NPS. In detail, the estimated NPS discharges were respectively $8,274\;kg\;N/km^2$/year from agricultural area, $730\;kg\;N/km^2$/year from forest and $7,657\;kg\;N/km^2$/year from the other land areas such as urban and industrial area.