• 한국태양에너지학회:학술대회논문집
• /
• 한국태양에너지학회 2009년도 춘계학술발표대회 논문집
• /
• pp.250-255
• /
• 2009

This study was analyzed the long term performance of the demonstration system for solar energy desalination in Jeju. we used a solar thermal system as heat source of the single-stage fresh water generator with plate-type heat exchangers and a photovoltaic power system as electric source for hydraulic pumps. The demonstration system was designed and installed at Jeju-island in 2006. The system was comprised of the desalination unit with daily fresh water capacity designed as $2m^3$ a $120m^2$ evacuated tubular solar collector to supply the heat, a $6m^3$ heat storage tank, and a 5kW photovoltaic power generation to supply the electricity of hydraulic pumps for the heat medium fluids. Through the operation during about 3 years, In a clear day more than $400W/m^2$, the daily fresh water showed to produce more than about 500liter, and from January, 2007 to March, 2009 for 3 years, solar irradiance daily averaged was measured $370W/m^2$, the daily fresh water yield showed that can be produced about 330liter.

• Journal of Microbiology and Biotechnology
• /
• 제29권11호
• /
• pp.1777-1789
• /
• 2019

Drought is more concerned to be a huge problem for agriculture as it affects plant growth and yield. Endophytic bacteria act as plant growth promoting bacteria that have roles for improving plant growth under stress conditions. The properties of four strains of endophytic bacteria were determined under water deficit medium with 20% polyethylene glycol. Bacillus aquimaris strain 3.13 showed high 1-aminocyclopropane-1-carboxylate (ACC) deaminase production; Micrococcus luteus strain 4.43 produced indole acetic acid (IAA). Exopolysaccharide production was high in Bacillus methylotrophicus strain 5.18 while Bacillus sp. strain 5.2 did not show major properties for drought response. Inoculation of endophytic bacteria into plants, strain 3.13 and 4.43 increased height, shoot and root weight, root length, root diameter, root volume, root area and root surface of Jerusalem artichoke grown under water limitation, clearly shown in water supply at 1/3 of available water. These increases were caused by bacteria ACC deaminase and IAA production; moreover, strain 4.43 boosted leaf area and chlorophyll levels, leading to increased photosynthesis under drought at 60 days of planting. The harvest index was high in the treatment with strain 4.43 and 3.13 under 1/3 of available water, promoting tuber numbers and tuber weight. Inulin content was unchanged in the control between well-watered and drought conditions. In comparison, inulin levels were higher in the endophytic bacteria treatment under both conditions, although yields dipped under drought. Thus, the endophytic bacteria promoted in plant growth and yield under drought; they had outstanding function in the enhancement of inulin content under well-watered condition.

• 한국농공학회지
• /
• 제17권4호
• /
• pp.4001-4008
• /
• 1975

The economic evaluation of the feasibility of expanding fully irrgated agriculture in the Ogseo project must consider preproject yields of rice under rainfed and partially irrigated paddy cultivation in order to assess incremental incomes from irrigation. Statistical data on yields available from official sources and field surveys conducted in the project area do not specify whether given unit yields refer to actually cropped or potentially cropped lands. This latter factor obviously affects any evaluation of marginal benefits to be derived from irrigation as the extent of rainfed areas actually cropped varies from year to year according to rain fall at the critical growth periods for low land rice. Although less dependent on direct rainfall, yields from partially irrigated lands are also highly affected by seasonal rainfalls. In this paper on attempt has been made to determine average yield under rainfed and partially irrigated conditions by relating yields to a available water. For rainfed paddy cultivation, the analysis discriminates between effects of rain deficiencies during transplanting and subsquent growth periods. For partially irrigated paddy cultivation, seasonal rainfalls have been considered, implying sufficient storage capacity for supplementary irrigation. The average yield of rainfed paddy has been calculated as 2.11 t/ha and that of partially irrigated paddy as 2.8 t/ha. Assuming even division between these two water supply patterns of areas not fully irrigated, a composite yield of 2.46 t/ha is oftained. This figure will be adopted as the basis for the on-going studies and project evaluation.

• 상하수도학회지
• /
• 제28권1호
• /
• pp.55-60
• /
• 2014

Food waste leachate (FWL) is a serious pollutant waste coming from the food waste recycling facilities in Korea. FWL has a high organic matter content and high COD to nitrogen (COD/N) ratio, which can disturb efficient methane production in the anaerobic digestion of FWL. In the present study a microalga, Clorella vulgaris (C.V), was used as co-substrate for the FWL anaerobic digestion in order to supply nutrients, decrease the COD/N ratio and increase its methane yield. Different co-digestion mixtures (COD/N ratios) were studied by using biochemical methane potential test and modified Gompertz equation for kinetic study. Mixed substrate of FWL and C. vulgaris in the co-digestion clearly showed more the biomethane yield than the sole substrates. The maximum methane production, 827.7 mL-$CH_4$/g-VS added, was obtained for COD/N ratio of 24/1, whereas the highest improvement of methane yield was found for COD/N ratio of 15/1.

• 한국농공학회논문집
• /
• 제59권1호
• /
• pp.45-55
• /
• 2017

Climate change causes changes in rainfall patterns, temperature and drought frequency. Climate change impact influences on water management and crop production. It is critical issue in agricultural industry. Rice is a staple cereal crop in South Korea and Korea uses a ponding system for its paddy fields which requires a significant amount of water. In addition, water supply has inter-relationship with crop production which indicates water productivity. Therefore, it is important to assess overall impacts of climate change on water resource and crop production. A water footprint concept is an indicator which shows relationship between water use and crop yield. In addition, it generally composed of three components depending on water resources: green, blue, grey water. This study analyzed the change trend of water footprint of paddy rice under the climate change. The downscaled climate data from HadGEM3-RA based on RCP 8.5 scenario was applied as future periods (2020s, 2050s, 2080s), and historical climate data was set to base line (1990s). Depending on agro-climatic zones, Suwon and Jeonju were selected for study area. A yield of paddy rice was simulated by using FAO-AquaCrop 5.0, which is a water-driven crop model. Model was calibrated by adjusting parameters and was validated by Mann-Whitney U test statistically. The means of water footprint were projected increase by 55 % (2020s), 51 % (2050s) and 48 % (2080s), respectively, from the baseline value of $767m^2/ton$ in Suwon. In case of Jeonju, total water footprint was projected to increase by 46 % (2020s), 45 % (2050s), 12 % (2080s), respectively, from the baseline value of $765m^2/ton$. The results are expected to be useful for paddy water management and operation of water supply system and apply in establishing long-term policies for agricultural water resources.

• 기술사
• /
• 제1권1호
• /
• pp.18-25
• /
• 1968

Higher yield in rice paddies is greatly dependent on adequately balanced and timely supply of water. A majority of rice paddy in Korea is generally irrigated by rainfall, but in many cases it has to be supplemented by artificial irrigation for optimum rice culture. Although the water requirement of rice plant is for higher Than that of athec crops, submerged condition of rice paddy is not Necessarily required. The moisture requirement of rice plant varies with its growing stages, and it is possible to increase the irrigation efficiency through reduction of water loss due to percolation in rice paddies. An experimental plots were set up by means of sandomized block design with three duplication; (a) All time submerged, (b) Economically controlled, and (c) Extremely controlled. Three different irrigation periods Were (a) Initial sage, (b) Inter-stage, and (c) Yast stage. The topsoil of the three plots were excavated to the depth of 30 cm and then compacted with clay of 6 cm thickness. There after, they were piled up with the excavated top soils, leveled and cored with clay of 6 cm thickness around footpath in order to prevent leakage. The results obtained from the experiments are as follows, 1. There is no difference among the three experiments plots in terms of physical and chemical conditions, soil properties, and other characteristics. 2. Culm length and ear length are not affected by different irrigation methods. 3. There is no difference in the mature rate and 1, 000 grain weight of rice for the three plots. 4. The control plot which was irrigated every three days shows an increased yield over the all the time submerged plot by 17.8 percent. 5. The clay lined plot whose water holding capacity was held 5 days long, needs only to be irrigated every 7 days. 6. The clay lined plot shows an increased yield over the untreated plot ; over all-the-time submerged plot by 18 percent ; extremely controlled plot by 18 percent, and economically controlled plot by 33 percent. 7. It may be saved in water requirement about one Thirds.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2000년도 하계학술대회 논문집 C
• /
• pp.2141-2143
• /
• 2000

In this paper, high concentration yield multi-discharge type ozonizer (MDO) of new discharge type using superposed silent discharge was designed and manufactured, MDO can be consisted with 3 kind of multi discharge type ozonizer (MDO) in accordance with power supply method that supplying power, which has 180[$^{\circ}$] phase difference, to 3 electrodes and double gap. At the moment, discharge characteristics and ozone generation characteristics of each MDO were investigated in accordance with quantity of supplied gas, the number of MDO, and the shapes of each MDO. In result, ozone generation characteristics of 17185[ppm] and 783[g/kWh] were obtained, and when ozone of 17185 [ppm] was in contact with dyeing water waste, decolorization characteristics was excellent, so it confirmed that MDO could be used as water environment improvement facility.

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제27권2호
• /
• pp.24-35
• /
• 2022

This study was conducted to estimate groundwater demand and supply for agricultural activities in a frequent-drought area that requires implementation of optimal distribution plan utilizing the well-network system (WNS). The WNS has been considered as a viable strategic way of supplying groundwater to farmlands by connecting groundwater wells physically or virtually. The study area heavily relied on groundwater resources for irrigation up to 53% due to a lack of surface water resources. Two kinds of methods, HOMWRS software and FAO approach, were used for estimating irrigation water requirements for paddy and upland fields, respectively. During the latest 10 years (2010~2019), the water requirements was estimated to be 1,106 m³/day. The requirements notably increased to 1,121~4,004 m³/day during active farming season (May to September), which exceeded the total yield capacity of pre-existing groundwater wells (2,356 m³/day) in the area. Detailed and definite determination for groundwater demand and supply helped to determine optimal scale parameters of WNS. The WNS has achieved more balanced distribution of groundwater resources for irrigation over the study area.

• 물과 미래
• /
• 제18권3호
• /
• pp.253-264
• /
• 1985

근본적으로 저수지의 Storage-Yield 관계를 해석하는 데는 두가지 관점이 있다. 가장 보편적인 관점은 필요한 수요량을 공급하기 위하여 저수지의 필요저수용량을 결정하는 것이다. 이런 형태의 문제는 저수지의 계획이나 초기 설계단계에서 보통 생긴다. 두 번째 관점은 주어진 저수용량에 대한 방류량의 결정이며, 이것은 최종 설계나 더 상세한 분석을 위한 현존 저수지의 재평가에서 자주 생긴다. 본 연구의 목적은 저수지의 설계나 운영을 위한 Storage-Yield 관계를 산정하는 현재의 방법론을 개선하는 것이다. 저수지의 Storage-Yield 관계를 해석하느 s가장 적합한 기법을 찾기 위하여 잔차누가곡선기법(Residual mass curve technique), 개선된 저류량기법(Low flow technique)과 TPM 기법(Transition probability matrix technique)이 검토되었다. 저수지의 Storage-Yield 관계를 해석하는데 있어서 홍천댐 건설예정지점의 1917∼1940년 월유입량 자료와 Thomas-Fiering 모델에 의해 모의 발생된 자료를 가지고 위의 세가지 기법을 상세히 검토하였다. 저수지의 Storage-Yield 관계를 폭넓게 검토한 결과, 잔차누가곡선기법과 저류량기법은 예비 설계에 타당하며, TPM 기법은 월별 혹은 계절별 수요변동을 고려할 수 있기 때문에 최종 설계에 타당한 기법임을 알 수 있다.

• 생물환경조절학회지
• /
• 제29권4호
• /
• pp.421-427
• /
• 2020

본 시험에서는 블루베리 양액재배시 양분공급시기가 수체 생육과 과실품질에 어떤 영향을 미치는지 알아보고자 수행하였다. 신초생장은 1차, 2차 생장량은 비슷한 경향이었으나, 3차 생장량은 수확종료 15일 전 중단한 처리에 비해 수확종료 직후와 수확종료 후 15일에 공급을 중단한 처리가 각각 15.4%, 15.6% 생장을 많이 하는 경향이었고, 수확종료 후 60일에 양분공급을 중단한 처리는 수확종료 15일전에 중단한 처리보다 3차 생장량이 53.2% 증가하는 경향이었다. 양액공급 후 이듬해 꽃눈수를 조사한 결과 수확종료 후 60일에 양분 공급을 중단한 처리는 수확종료 15일전에 중단한 처리보다 26% 적었다. 처리별 과실특성은 과실중, 당도, 산도 등은 처리간 큰 차이가 없었으며, 주당 수량은 수확종료 15일전이 2.1kg, 수확종료 직후와 수확종료 후 15일에 양분을 중단한 처리가 2.5kg으로 가장 많았으며, 수확종료 후 45일과 60일에 양분을 중단한 처리는 1.8kg으로 가장 작았다.