• 지질공학
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• 제21권3호
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• pp.239-246
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• 2011

건설 현장에서 대규모의 풍화토 지반을 만나게 되면, 지반구조물의 설계 및 시공에 있어서 계획변경을 수반하게 된다. 풍화토는 대부분 공기중에 노출됨과 동시에 풍화가 급속하게 진행되어 토공구조물에 심각한 영향을 줄 수 있으며, 입도가 불량하고 수분에 민감하여 다짐관리가 어렵다. 이러한 풍화토는 공학적인 성질이 지역적으로 대단히 다르게 나타나는 경우가 많아서 지역적 특성을 연구하여 보고하는 것이 중요하다. 본 연구에서는 강원도 간성지역에서 존재하는 화강풍화토를 발생된 현장 2곳에서 각각 23개소, 8개소 채취하여 지질학적으로 고찰한 후, XRD분석, 입도, 연경도, 다짐특성을 분석하고, 도로 토공재료로서의 평가를 위하여 CBR값과 균등계수, 200체 통과율, 2 mm 이상 골재 함유율과의 연관성을 분석하였다. 그 결과, 연구대상 지역의 화강풍화토는 2 mm이상의 골재함유량이 CBR값에 영향을 크게 주는 것으로 파악되었으며, 기준미달토등에 대하여 2 mm이상의 골재를 혼합하여 토질을 개선할 수 있을 것으로 판단되었다.

• 한국방재안전학회논문집
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• 제14권3호
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• pp.51-63
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• 2021

본 연구는 도심지 지하 교통망 건설 중 터널굴착 공정에 적용하는 차수·보강 그라우팅 공사의 품질향상을 위한 것이다. 기존의 터널 그라우팅 시공에서는 실시간으로 주입압 및 주입량을 보여주는 P~q~t charts를 기술적으로 온전히 활용하지 못하였다. 그 이유는 주입지반의 차이 및 주입 중 어떤 문제가 발생할 시에 P~q~t charts가 어떻게 변화하며, 그에 따른 표준적인 주입유형을 보여주는 주입 그래프 패턴, 특성, 판정, 그에 따른 조치유형 및 조치방법에 대한 기술적 판단방법이 없었기 때문이다. 본 논문은 상기의 문제점 등을 해결하기 위한 일환으로 일반 및 알고리즘 그라우팅 시 토사층 및 암반층으로 구분하여 주입유형, 특성, 판정방법, 그리고 조치유형 및 조치방법 등의 연구를 수행하였다. 새롭게 개선된 토사층 P~q~t charts에서는 일반그라우팅과 알고리즘 그라우팅 둘로 나누어 각각 6가지 유형으로 구분하였고 각 유형에 따른 특성 및 판정방법을 도출하였으며 일반주입유형과 알고리즘 주입유형에서의 각 유형별 조치방안도 개발하여 현장에서 쉽게 적용 가능하도록 제안하였다. 또한, 개선된 암반층 P~q~t charts에서도 각각 6가지 유형으로 구분하여 토사층과 같이 해당 유형에 상응하는 조치방안을 개발하여 현장에서 쉽게 적용 가능하도록 제안하였다. 따라서, 도심지 지하 교통망 건설 중 터널굴착 공정에 적용하는 차수·보강 그라우팅 공사에서 예비단계의 현장시험 혹은 시공 중 단계에서 시간에 따른 주입압 및 주입량의 데이터인 P~q~t charts를 실시간 측정하여 주입유형을 분석하고 조치방법을 마련하여 더 나아가 모든 그라우팅 단계에서 활용될 수 있을 것으로 기대된다.

• 한국유기농업학회지
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• 제27권4호
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• pp.453-461
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• 2019

본 연구는 옥수수 유기재배에서 대부분 수입에 의존하여 사용되고 있는 유박의 대체제 선발을 위해 아미노산액비와 퇴비차의 혼합처리를 평가하였다. 그 결과, 유기질 비료 성분 중 질소, 유효인산, 칼륨, 칼슘 및 마그네슘 함량은 유박 > 아미노산액비 > 퇴비차 순이었다. 이들 각각의 유기질 비료는 토양 화학성 변화에 대한 영향이 미미하였다. 옥수수 생육량 중 이삭중에 대해 아미노산액비 및 유박 단독처리가 유의성이 있었고 100립 생체중에 대해서는 모든 처리가 무처리와 비교하여 유의한 증가를 보였다. 이들 퇴비차, 아미노산액비 및 유박 단독처리는 옥수수 상품성 수량을 무처리 대비 각각 3.9, 5.4 및 5.9% 향상시켰다. 한편, 유박 대체제 선발을 위하여 퇴비차와 아미노산액비를 혼합 처리한 결과, 혼합처리도 토양 화학성 변화에 영향이 미미하였다. 생육량에서는 착수고, 착립장, 이삭중 및 100립 생체 중에서 유박 단독처리와 비교하여 혼합처리가 유의성 있는 증가를 보였고 혼합처리에 의한 상품성 수량은 유박 단독처리 대비 3.9% 향상되었다. 따라서, 아미노산액비와 퇴비차의 혼합처리는 유박을 대체할 수 있는 유기농자재 중 하나라고 판단한다.

• 원예과학기술지
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• 제17권2호
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• pp.115-117
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• 1999

완숙계 대과종 토마토를 공시 재료로 재배시기와 재배방식을 달리하여 생육 및 수량, 품질 및 저장성 등을 비교 조사하고자 하였다. 토마토는 재배방식에 따른 생육 및 수량의 차이를 나타내지 않았으나 재배시기에 따라서는 여름재배에서 작물의 생육이 왕성하였고 주당 수량도 여름재배에서 많았다. 토마토 과실의 수분함량은 재배방식의 차이보다는 재배시기에 따른 차이가 커 여름 수확과의 수분함량이 봄 수확과 보다 높은 수치를 보여주었다. 토마토 과실의 경도는 재배방식간에는 차이가 없거나 적은 반면 재배시기에 따라서는 약간의 유의성이 있는 차이를 보였는데 봄 수확과에 비해 여름 수확과에서 경도가 높았다. 토마토의 전당, 포도당, 과당 함량 등은 모두 여름 수확과에 비해 봄 수확과에서 높았고 재배방식별로는 유의성 있는 차이를 보여주지 않았다. 토마토 과실의 실온저장시 수분손실량은 양액재배 수확과가 적었고, 수확기에 따라서는 여름 수확과가 적었다. 실온에서 녹숙과의 과피 변색은 봄보다는 여름수확 과실이, 토양보다는 양액재배 과실이 빠르게 진행되었다.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.318-318
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• 2017

This study was conducted to find optimum mixed sowing ratio of green manure crops to reduce the use of chemical fertilizer as well as to increase the crop yield potential which will foster the utilization of green manure crops in the upland field in view of environment friendly agriculture. According to the study, the mixed ratio, 50:50, of hairy vetch and green barley showed highest nitrogen production yield in the soil due to the relatively higher organic nitrogen supply from the hairy vetch plant as well as nitrogen fixation from the air rather than other mixed ratio. In the 50:50 mixed ratio of hairy vetch and green barely total nitrogen amount in the soil showed 17.2kg per 10a, but in the other treatment ratio such as 75:25, 25:75. total nitrogen fixation amount were 16.7, 16.9 respectively. We also conducted the experiment to compare the effect of the mixed sowing treatment of green manure crops on the production of corn cultivated as a succeeding plant of hairy vetch. According to the result, the mixed ratio, 50:50, of hairy vetch and green barley treatment showed highest yield potential of corn as 153kg per 10a in seed weight which is due to the relatively higher organic nitrogen supply from the hairy vetch plant as well as nitrogen fixation from the air rather than other mixed ratio. In the mixed sowing treatment of hairy vetch 100 and barley 0 ratio, the corn production showed 148kg per 10a which is 5kg lower than that of hairy vetch 50 and barley 50 ratio, but showed statistically no difference between those two treatment. Otherwise, different treatments, such as hairy vetch 75 and barley 25, 25 and 75, 0 and 100 showed statistically different each other. Therefore, it was concluded that green manure crops, such as hairy vetch, green barley and rye were very effective crops to increase the soil fertility and gave the positive effect to the crops to give vegetative and propagative growth condition and, in turn, increased the yield potential. We have to make policy to enhance the utility of green manure crops in the upland crops as well as faddy field for the soil fertility and crop yield production which will guarantee prominent quality of environment friendly agriculture products.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.233-233
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• 2017

Algal communities are important to maintain the aquatic ecosystems function. Algae have short life cycles, they respond quickly to environmental change and their diversity and density can indicate and the quality of their habitat. The bloom forms before the rice seedings have emerged, it may present a physical barrier that prevents the seedlings from penetrating the floodwater. Wind may also move the algal bloom, pushing the young plants beneath the surface. Another harmful action develops when the water dries up and the algae form a layer at the bottom of the field. The layer envelops the seedlings, which are not yet deeply rooted, and drag them to the surface when the water is let in again. Soil utilization pattern can be the mail facter affecting soil physico-chemical properties, especially in soil phosphorus (P). Solid content of the algae culture solution increased with the increase in the nitrogen rather the phosphors concentration. Phosphoric acid was treated with conventional treatments (100-0%, before transplanting time-tillering stage), 50-50%, 0-100%, and un-treated. The herbicide was treated on the 7 DAT (day after transplanting). Green algae samples were collected 20 DAT. Total phosphoric acid was the highest at 0.06 in 50-50% treatment in 20 DAT. The amount of green algae was about twice (9.8 mg/20ml) that of un-treated. Total number of green algae was 54 species(Green algae 35 species, Euglena 9 species, Stone wheel 10 species). Among the phosphoric acid treatment methods, the number of occurrences of green algae were the highest with 39 species in 0-100%, followed by 50-50%, 28 species, conventional treatments, 22 species, non-treatment, 18 species, respectively. Rice Yield was not significantly different by phosphoric treatment time, but slightly higher than un-treated. The maximal algal biomass was observed about 2weeks or 1 month after transplanting; the subsequent decrease of the biomass was related to the consumption by grazers and to a deficient light under the rice canopy. Maximal algal growth was observed just before tillering. To estimate the suitable method of phosphorus application in puddled-soil drill seeding of rice, available phosphorus appearance of algal water bloom, and rice yield were investigated in paddy soil of rice-barley double cropping system.

• 한국물환경학회지
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• 제27권6호
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• pp.855-861
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• 2011

Short-term effects of current velocity and turbid water on the benthic diatom community and water quality were examined in artificial channel ($20{\times}200{\times}10cm$) with two different experiments. The first and second experiments were consisted of different current velocities such as 1 L/min., and 1, 3, and 6 L/min., respectively. The concentration of turbid water is prepared with loess and fixed at 10 and 20 times of the turbidity of control inflow (10 NTU, LTW), respectively. At experiment 1 (EXP-1), introduction of turbid water increased dissolved oxygen, electric conductivity, pH and turbidity, but there were no differences between low- (100 NTU, MTW) and high-turbid water (200 NTU, HTW). However, experiment 2 (EXP-2) did not change any environmental parameters except dissolved total and inorganic nitrogen like EXP-1. MTW in EXP-1 strongly stimulated the growth of benthic diatom, while both MTW (150 NTU) and HTW (300 NTU) in EXP-2 did not increase or decrease the diatom abundance. Over the study, the dominant species was four, Aulacoseira ambigua, Cyclotella stelligera, Aulacoseira granulata and Achnanthes minutissima. In EXP-1, two highest species in abundance, A. ambigua and A. granulata were highly grown in MTW, while Achnanthes minutissima high in HTW adversely. These results indicate that the introduction of turbid water can play an important role in the shift of water quality and benthic diatom community in stream ecosystem, especially inflow of soil water in low current velocity.

• 인간식물환경학회지
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• 제24권4호
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• pp.311-327
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• 2021

Background and objective: Recent urban agriculture meets the needs of urban residents that safety and avoids using chemical pesticides. This study was conducted to identify various factors of companion planting affecting the growth of cherry tomatoes, which will promoting urban agriculture by improving socioeconomic satisfaction with gardening activities through quality. Methods: Four types of companion plants such as marigold, zinnia, spearmint and basil, that have a companion effect with growth, sugar content, and vitamin C content. We obtained the mean and standard deviation and tested the significance at a 95% confidence level (p < .05) with Duncan's multiple range test after one way ANOVA and MANOVA. Results: Compared to monoculture of cherry tomatoes, the plant growth in the treatment plots with companion planting showed a significant increase overall(p < .05), but there wasn't interaction effect among companion plants, planting ratio and type. As for the absorption of inorganic components, the companion planting showed better absorption than monoculture of cherry tomatoes, as favorable growth, and there was an interaction effect among the individual factors. The sugar content was higher than the standard sugar content of 5.8 brix in both the treatment plots at the control, and vitamin C content was higher than the control at 26.27mg/100g in all treatment plots, but there wasn't statistically significant difference. The soil pH in the cultivation plot ranges from 5.5 to 9.0 and was weakly alkaline in all treatment plots except zinnia, showing low contents of phosphoric acid, exchageable potassium, calcium and magnesium. Conclusion: This study was conducted to analyze various factors such as the growth of cherry tomatoes, contents of inorganic components, sugar content and vitamin C content of fruits, and soil analysis according to companion plants, planting type, and planting ratio. We will study sugar content by measuring the change in growth every phase of fruits.

• 한국농공학회논문집
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• 제61권4호
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• pp.33-42
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• 2019

In this study, the channel and floodplain widths are indirectly measured for three different watersheds using satellite images to reflect the shape of Korean channels in the Soil and Water Assessment Tool (SWAT) model. For measuring the channel and floodplain widths, multiple satellite images were referred to ensure the widest width of certain points. In the single channel, the widths at the multiple points were measured. Based on the measured data, the regression equations were derived to estimate the channel and floodplain widths according to watershed areas. Applying these developed equations, this study evaluated the effect of the change of channel and floodplain widths on the SWAT simulation by comparing to the measured streamflow data. The developed equations estimated larger channel width and smaller floodplain compared with those calculated in the current SWAT model. As shown in the results, there was no considerable changes in the predicted streamflow using the current and developed equations. However, the flow velocity and channel depth calculated from the developed equations were smaller than those of the current equations. The differences were caused by the effect of different channel geometries used for calculating the hydraulic characteristics. The channel geometries also affected the water quality simulation in channels because the hydraulic characteristics calculated by the channel geometries are directly related to the water quality simulation. Therefore, application of the river cross-sectional regression equation reflecting the domestic stream shape is necessary for accurate water quantity / quality and water ecosystem simulation using hydrological model.

• 한국물환경학회지
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• 제32권2호
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• pp.183-190
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• 2016

Monitored data (rainfall runoff and water quality) from 4 different paddy sites over 3 years were compared to analyze the effect of irrigation water management on irrigation supply and rainfall runoff quality in Korea. The system of rice intensification water management was adopted at one site (SRI) while the conventional water management method was used for rice culture at the other three sites (CT, SD and HD). The soil texture at SRI, CT and SD was sandy loam while that at HD was silt loam. The average reduction of irrigation supply at SRI compared with CT, SD and HD during the 3 years studied was 49%, 51% and 55%, respectively. The average event mean concentration (EMC) at SRI compared with that at CT, SD and HD was decreased by 35% (BOD), 44% (COD), 47% (SS), 19% (TN) and 38% (TP). The correlation between rainfall runoff and the measured non-point source (NPS) pollutants was very good in general. The comparison revealed that SRI water management significantly reduced both irrigation supply and EMC in rainfall runoff. Paddy NPS pollution was closely related to factors that induce runoff such as rainfall and irrigation supply. It was concluded that SRI management could be an effective and practical option to cope with both water shortage due to climate change and water quality improvement in rural watersheds. However, further studies are recommended in large irrigation districts for use in the development and implementation of NPS pollution policies since the data was collected from field sized paddies.