• 한국토양비료학회지
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• 제27권3호
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• pp.189-194
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• 1994

신개간경사지(新開墾傾斜地)에서 생산력 증대를 위한 물리화학적인 개량방법(改良方法)과 고구마 재배에 대한 기초자료를 얻고자 1985년부터 4년간 송정양토(松汀壤土)에서 고구마를 재배하면서 토양물리화학성의 년차간(年次間) 변화량(變化量)과 변화율(變化率) 및 고구마의 수량을 조사, 분석하였다. 1. 토양의 용적밀도는 토심(土深)에 관계없이 2년차부터 계속 높아졌으나 경도(硬度)는 표토에서는 같은 경향이나 심토에서는 일정한 경향이 없었다. 2. 고구마의 4년간 평균수량(平均收量)은 종합개량구(綜合改良區)에서 32.68ton/ha으로 제일 많았고 대조구(對照區)에 비해 59% 증수(增收)되었으며 처리별로는 인산구>심경구>석회구>퇴비구>대조구 순으로 많았다. 3. 년차간(年次間) 고구마 수량과 토양의 물리화학성과의 상관계수는 표토에서는 용적밀도, 경도, 양이온치환용량과 심토에서는 용적밀도, 토양수분, 양이온치환용량과 유의성이 높았다. 4. 토양의 물리화학성 변화률(變化率)과 고구마 수량(收量)과의 상관관계(相關關係)는 유기물 함량을 제외한 다른 특성과 유의성이 있었고 개량제(改良劑) 시용(施用)이 없었던 4년차에 토양(土壤)의 물리화학성(物理化學性)이 악화(惡化)되었음을 알 수 있었다.

• 한국안광학회지
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• 제21권3호
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• pp.265-274
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• 2016

목적: 본 연구에서는 신축사무실 건물 및 재실자를 대상으로 식물적용에 따른 안구건조 증상 및 실내공기질 등에 대한 변화를 평가하고자 하였다. 방법: 세종시 정부청사 신축건물 및 사무실 재실자를 대상으로 하였다. 식물적용에 따라 실내공기질을 측정하였으며, 휘발성유기화합물류와 알데하이드류 및 온 습도를 측정하여 평가하였다. 안구건조 증상은 Ocular surface disease index(OSDI)를 이용하여 정상, 경도, 중등도, 및 중증으로 분류하여 측정하였다. 결과: 식물적용사무실에서 휘발성유기화합물류의 감소율이 다소 높게 나타나 식물적용으로 인한 저감효과가 있는 것으로 조사되었다. 식물적용 재실자에서 새건물증후군 증상 점수가 점차적으로 감소하였고, 식물미적용사무실 재실자에서는 새건물증후군 증상 점수가 상승하였다. 재실자의 안구건조설문결과에서 통계적으로 유의한 차이는 관찰되지 않았다. 결론: 식물적용 사무실 내 유해물질의 감소효과가 있었고, 재실자를 통한 설문조사결과 안구건조 및 새건물증후군 증상에 긍정적인 효과는 있었다. 개인의 민감도 등에 의한 차이 및 현장조사로 인한 연구의 제한점 등을 보완한 장기 연구가 필요하다.

• 한국응용곤충학회지
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• 제55권4호
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• pp.383-388
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• 2016

전북 부안지역에서 오디용 뽕나무에 발생하는 뽕나무이의 발생 양상과 친환경자재에 의한 방제 효과를 조사하였다. 뽕나무이 월동 성충은 3월 하순부터 5월 중순까지 뽕나무 포장으로 비래하였으며 발생최성기는 4월 중순이었다. 알은 4월 중순부터 관찰되었으며 약충은 5월 상순부터 부화하기 시작하여 5월 중순에 발생피크를 나타냈다. 신성충은 6월 상순부터 관찰되었으며 이후 비산하여 6월 중순 이후에는 뽕나무 포장에서 관찰되지 않았다. 따라서 뽕나무이의 발생소장에 의한 방제 적기로 월동 성충은 4월 중순, 약충은 5월 상순으로 판단되었다. 뽕나무이 약충 방제에 고삼 추출물과 데리스 추출물이 효과적이었으며, 뽕나무 포장에서 뽕나무이 약충 방제적기에 데리스 제제를 5일 간격으로 2~3회 처리한 결과 방제 효과가 높았다.

• 한국농공학회지
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• 제17권1호
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• pp.3627-3641
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• 1975

The Government is trying to increase total food grain yield to meet national self sufficiency by means of increasing unit yield as well as extending crop land, and this year he set the target of 321,000 hectare of forest to clear for cropping. This study was carried to investigate the most efficient method of clearing hillock by bulldozer, and successful method to develope yielding potential of newly cleared land in short term. Since the conventional land clearing method is just earth leveling and root removing neglecting top soil treatment, the growth of crop was poor and farmer tends not to care the land. The top-soil-furrowing method is applied through out this study, that is advantageous especially for the land having shallow top soil and low fertility like Korean forest. In this study, various operating method were tried to find out most efficient method separately in connection with the land slope less than 25 percent and over, and several fertilizing methods to develop yielding potential. The results are as follows; 1) For the natural land slope utilization method, applicable to the land having less than 25 percent slope, reverse operating was more efficient than using forward gear of bulldozer. The operating time was 3 hour 32 minutes and 36 seconds using forward gear was 2 hour 32 minutes and 30 seconds for reverse gear operation per 1,000 square meter. 2) Bulldozer having angle blade adjustment needed 7hr 15min. for constructing of terrace per 10a compaire with the one having angle & tilt adjustment needed 6hr 4min for same operations. Specially there is significant difference for operation time of first period (earth cutting) such as bulldozer having angle blade adjustment needed 3hr 56min compaired with the one having angle & tilt adjustment 3hr 59min. In construction of terrace, the bull-dozer having tilting and angle blade adjustment was most suitable and performed efficiently. 3) For the fertilizer application treatment, the grass (Ladino clover) yield in first year was almost same as ordinary field's in the plot applied(N.P.K+lime+manure) while none fertilizer plot showed one tenth of it, and (N.P.K.+lime) applied plot yielded on third. 4) The effect of different land clearing method to yield showed significant difference between each treatment especially in the first year, and the conventional method was the lowest. In the second year, still conventional terracing plot yielded only half of ordinary field while the other plots showed as same as ordinary field's. 5) The downward top soil treatment plot showed most rapid improvement in soil structure during one year physio chemically, it showed increase in pH rate and organic composition, and the soil changed gradually from loam to sand-loam and the moisture content increased against the pF rate, and it gives good condition to grow hay due to the increase of field water capacity with higher available water content. 6) Since the soil of tested area was granite, the rate of soil errosion was increased about 2 to 5 percent influencing in soil structure more sand reducing clay content, and an optimum contour farming method should be prepared as a counter measure of errosion.

• 농업과학연구
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• 제43권4호
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• pp.537-546
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• 2016

The development of models for agriculture systems, especially for crop production, has supported the prediction of crop yields under various environmental change scenarios and the selection of better crop species or cultivar. Crop models could be used as tools for supporting reasonable nutrient management approaches for agricultural land. This paper outlines the simplified structure of main crop models (crop growth model, crop-soil model, and crop-soil-environment model) frequently used in agricultural systems and shows diverse application of their simulated results. Crop growth models such as LINTUL, SUCROS, could provide simulated data for daily growth, potential production, and photosynthesis assimilate partitioning to various organs with different physiological stages, and for evaluating crop nutrient demand. Crop-Soil models (DSSAT, APSIM, WOFOST, QUEFTS) simulate growth, development, and yields of crops; soil processes describing nutrient uptake from root zone; and soil nutrient supply capability, e.g., mineralization/decomposition of soil organic matter. The crop model built for the DSSAT family software has limitations in spatial variability due to its simulation mechanism based on a single homogeneous field unit. To introduce well-performing crop models, the potential applications for crop-soil-environment models such as DSSAT, APSIM, or even a newly designed model, should first be compared. The parameterization of various crops under different cultivation conditions like those of intensive farming systems common in Korea, shortened crop growth period, should be considered as well as various resource inputs.

• Advances in environmental research
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• 제6권2호
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• pp.127-137
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• 2017

Cotton is the major fiber crop in Pakistan that accounts for 2% of total national gross domestic product (GDP). After picking of cotton, the dry stalks are major organic waste that has no fate except burning to cook food in villages. Present research focuses use of cotton stalks as feedstock for biochar production, its characterization and effects on soil characteristics. Dry cotton stalks collected from agricultural field of Bahauddin Zakariya University, Multan, Pakistan were combusted under anaerobic conditions at $450^{\circ}C$. The physicochemical analysis of biochar and cotton stalks show higher values of % total carbon, phosphorus and potassium concentrations in biochar as compared to cotton stalks. The concentration of nitrogen was decreased in biochar. Similarly biochar had greater values of fixed carbon that suggest its role for carbon sequestration and as a soil amendment. The fourier transformation infrared spectroscopic spectra (FTIR) of cotton stalks and biochar exposed more acidic groups in biochar as compared to cotton stalks. The newly developed functional groups in biochar have vital role in increasing surface properties, cation exchange capacity, and water holding capacity, and are responsible for heavy metal remediation in contaminated soil. In a further test, results show increase in the water holding capacity and nutrient retention by a sandy soil amended with biochar. It is concluded that cotton stalks can be effectively used to prepare biochar.

• Corrosion Science and Technology
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• 제7권5호
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• pp.269-273
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• 2008

It is known that the fluoric resin has the most outstanding properties in the extremely acidic environment of high temperature. However, this resin is the thermal hardening type that needs long time heat treatments above $250^{\circ}C$. It's impossible to use in situ in the extremely acidic environment such as a huge FGD ductworks or industrial chemical tanks. Furthermore, even the natural hardening type fluoric coatings which can be hardened less than $120^{\circ}C$ can not be applied to the highly acidic environmental plants because of its chemical resistance. In this study, new fluoric coatings that has excellent thermal resistance, chemical resistance and corrosion resistance has been developed in order to solve above problems and to be applied to the large plant structures in the field. These newly developed coatings are organic and inorganic composite type that have fluoric rubber(100 wt%), fluoric resin(5~50 wt%), oxalates(5~30 wt%), inorganic fillers mixed with plate-type and bulk-type solids(20~150 wt%), hardeners(0.5~5 wt%), and hardening hasteners(0.1~3 wt%). The best chemical and physical properties of these coatings are acquired by variation of adhesive reinforcement agents, dispersants, leveling agents. Mixing ratios of plate-type and bulk-type inorganic fillers influence the thermal properties, abrasive resistance and chemical infiltration properties of coatings. The mixing control is also very important to have homogeneous surface and removing inner voids of coatings.

• 한국해양환경ㆍ에너지학회지
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• 제5권1호
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• pp.3-10
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• 2002

미세점착성 퇴적물 침강속도의 정량적 산정은 퇴적학적 측면에서뿐만 아니라 환경공학적 측면에서도 매우 중요한 과제이다. 미세점착성 퇴적물의 침강특성은 입자간의 충돌과 입자간의 점착으로 인하여 발생하는 응집에 의해 크게 영향을 받는다. 한편, 미세점착성 퇴적물의 응집강도는 광물질 구성, 입경분포, 유기물 함량 등으로 묘사되는 퇴적물의 물리ㆍ화학적 기본 특성에 따라 크게 변화하고, 이러한 물리ㆍ화학적 기본특성은 또한 지역적으로 변화하므로, 한 특정지역에서의 점착성 퇴적물의 침강특성은 현장관측이나 실내실험을 통하여 관측되어야만 한다. 본 연구에서는 최근 수행된 새만금 및 군산해역 점착성 퇴적물의 침강속도 관측 결과를 이용하여, 기존의 침강속도 경험식을 검토하고, 새로운 침강속도 곡선식이 개발된다. 새로 개발된 침강속도 곡선식은 기존의 복잡한 곡선식에 비해 단순하며, 측정치로부터의 계수산정이 편리하고, 또한 측정치의 변화 경향을 더욱 잘 나타낸다.

• 산업식품공학
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• 제21권3호
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• pp.233-241
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• 2017

Scaffolds of cell substrates are biophysical platforms for cell attachment, proliferation, and differentiation. They ultimately play a leading-edge role in the regeneration of tissues. Recent studies have shown the potential of bioactive scaffolds (i.e., osteo-inductive) through 3D printing. In this study, rice bran-derived biocomposite was fabricated for fused deposition modeling (FDM)-based 3D printing as a potential bone-graft analogue. Rice bran by-product was blended with poly caprolactone (PCL), a synthetic commercial biodegradable polymer. An extruder with extrusion process molding was adopted to manufacture the newly blended "green material." Processing conditions affected the performance of these blends. Bio-filament composite was characterized using field emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectroscopy (EDX). Mechanical characterization of bio-filament composite was carried out to determine stress-strain and compressive strength. Biological behaviors of bio-filament composites were also investigated by assessing cell cytotoxicity and water contact angle. EDX results of bio-filament composites indicated the presence of organic compounds. These bio-filament composites were found to have higher tensile strength than conventional PCL filament. They exhibited positive response in cytotoxicity. Biological analysis revealed better compatibility of r-PCL with rice bran. Such rice bran blended bio-filament composite was found to have higher elongation and strength compared to control PCL.

• Journal of Microbiology and Biotechnology
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• 제32권5호
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• pp.564-574
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• 2022

Microbial diversity in the soil is responsive to changes in soil composition. However, the impact of soil amendments on the diversity and structure of rare and abundant sub-communities in agricultural systems is poorly understood. We investigated the effects of different Chinese herb residue (CHR) soil amendments and cropping systems on bacterial rare and abundant sub-communities. Our results showed that the bacterial diversity and structure of these sub-communities in soil had a specific distribution under the application of different soil amendments. The CHR soil amendments with high nitrogen and organic matter additives significantly increased the relative abundance and stability of rare taxa, which increased the structural and functional redundancy of soil bacterial communities. Rare and abundant sub-communities also showed different preferences in terms of bacterial community composition, as the former was enriched with Bacteroidetes while the latter had more Alphaproteobacteria and Betaproteobacteria. All applications of soil amendments significantly improved soil quality of newly created farmlands in whole maize cropping system. Rare sub-communitiy genera Niastella and Ohtaekwangia were enriched during the maize cropping process, and Nitrososphaera was enriched under the application of simple amendment group soil. Thus, Chinese medicine residue soil amendments with appropriate additives could affect soil rare and abundant sub-communities and enhance physicochemical properties. These findings suggest that applying soil composite amendments based on CHR in the field could improve soil microbial diversity, microbial redundancy, and soil fertility for sustainable agriculture on the Loess Plateau.