• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2004년도 학술발표회
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• pp.646-650
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• 2004

The purpose of this study is to determine the optimal groundwater yield for a small rural watershed, which is necessary for effective groundwater management. The study area$(3.89km^2)$ is located in Kyungpook Sangju Yangchon-dong and hourly groundwater level in an observation well is observed and the data are used to verify the visual MODFLOW model. The groundwater model is applied in the same area to obtain optimal yield for 1992 and 1994, 1982. The optimal yield in this experimental watershed ranged $12.5\%\;to\;14.0\%$ of the annual infiltration rate.

• 수산해양교육연구
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• 제16권1호
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• pp.84-98
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• 2004

Due to a publicly owned resources, the overexploitation of the fisheries resources can result in externalities in the form of reduced future levels of yield. These problems can be theoretically improved through effective management of the fishery. The paper illustrates maximum sustainable yield(MSY), maximum economic yield(MEY) and F0.1 level of fishing mortality as the concept of optimal yield, and it theoretically shows that MSY is more appropriate for the optimal yield than MEY where prices increase even though MEY achieves the maximization of economic rent in a fishery assuming constant prices. And the paper presents several fisheries management tools and policies such as input controls, output controls and taxes. As the traditional approach to fishery management, input controls involve restrictions on the physical inputs into the production process(e.g. capital, time or technology) and output controls involve limits on the quantity of fish that can be landed. To introduce user cost into the harvest decisions of rent-seeking fishers, taxation, as a bioeconomic management policy of the fisheries, directly addresses the problems associated with the resource being unpriced. As most fisheries management plans, however, have increasing fisher income as an objective, taxes have not been introduced into any fisheries management policies despite their theoretical attraction.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2022년도 추계학술대회
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• pp.59-59
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• 2022

The transplanting date of rice affects grain yield and quality, and it is changed by the environment during cultivation. Thus, it is important to provide the optimal transplanting dates for rice growers under global warming environment. In this study, transplanting date experiments with thirty-day-old seedlings of three cultivars (early, mid, and mid-late maturity) were conducted at the National Institute of Crop Science in Suwon from 2018 to 2021 to determine the optimal transplanting dates for and quantify the effect of planting dates on yield and quality. Transplanting date was strongly associated with culitvar across every year. Clear relationships between transplanting date and head rice yield in early and mid-late maturing rice varieties were observed, and the highest head rice yields were observed during transplantings in mid and late June for early maturing cultivar and mid June for mid-late maturing cultivar. It is obvious that the optimal rice transplanting dates have been shifted and are better later than the optimal transplanting dates in 2002-2004. Days to heading was also strongly associated with the transplanting date and cultivar with 89% of the variation explained. Days to heading was reduced in the later transplanting dates. Grain yield was strongly associate with biomass production during ripening(R²=0.85), however translocated biomass from leaf and stem showed little association with grain yield. The results from this study reconfirmed the importance of shifting optimal transplanting dates to maximize head rice yield for the Mid-plain area in South Korea.

• 약학회지
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• 제46권5호
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• pp.364-368
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• 2002

Optimal synthetic conditions of barium sulfate were investigated from the viewpoint of yield and bulkiness according to a randomized complete block design proposed by Box and Wilson. Barium chloride and Sodium sulfate were utilized as reactants in order to prepare barium sulfate in this study. The optimum Synthesis conditions of barium sulfate obtained from this study are as follows; Reactant temperature; 60~75$^{\circ}C$ (viewpoint of yield) and 60~71$^{\circ}C$ (viewpoint of bulkiness). Concentration of two reactants; 12.7~14.4％ (viewpoint of yield) and 5~10.5％ (viewpoint of bulkiness). Mole ratio of two reactants, [BaCl$_2$]/[Na$_2$SO$_4$]; 1.62~1.96 (viewpoint of yield) and 2.0 (viewpoint of bulkiness). Reacting time; 13~15 minutes (viewpoint of yield) and 12~14 minutes (viewpoint of bulkiness). Drying temperature of product; 86~10$0^{\circ}C$ (viewpoint of yield) and 6$0^{\circ}C$ (viewpoint of bulkiness).

• 한국농공학회지
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• 제31권4호
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• pp.50-58
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• 1989

An approach to irrigation scheduling for chinese caggage is presented, and a crop yield response function to soil moisure is derived from irrigation experiments, based on a root- zone water balance method. The paper concludes that crop yield can be estimated by allowable depletion and actual evapotranspiration in 3 cropping stages, and presents the optimal allowalbe depletion, irriga- tion frequency and the amount of irrigation water to get the maximum crop yield and opti- mal irrigation policy.

• 대한지하수환경학회지
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• 제5권1호
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• pp.21-29
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• 1998

우리나라에서는 최근에 암반지하수 개발이 늘어나고 있으나 과잉 양수에 의한 암반지하수 고갈 및 수질오염이 우려된다. 따라서, 암반지하수 보존을 위해서는 양수정의 적정채수량을 정확히 파악하는 것이 매우 중요하다. 양수정의 적정채수량 결정을 위해서는 먼저 그 지역의 수리지질 특성에 맞은 지하수 모델을 이용하여 정확한 수리상수를 계산하는 것이 중요하다. 본 연구에서는 적합한 모델을 이용하여 암반대수층의 수리상수를 결정하고, 자연적인 함양량의 범위내에서 암반대수층의 적정채수량을 산정하는 방법을 제시하였으며, 이 적정채수량 결정방법을 부산시 금련산에서 수행한 5개 굴착공의 양수시험에 적용하여 그 적용성을 분석하였다.

• Journal of Ecology and Environment
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• 제41권7호
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• pp.191-201
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• 2017

Background: Limited availability of corn stover due to the competing uses (organic manure, animal feed, bio-materials, and bioenergy) presents a major concern for its future in the bio-economy. Furthermore, biomass research has exhibited different results due to the differences in the supply of enzymes and dissimilar analytical methods. The effect of the two leading pretreatment techniques (dilute acid and alkaline) on glucose yield from three corn stover fractions (cob, stalk, and leaf) sourced from a single harvest in Uganda were studied at temperatures 100, 120, 140, and $160^{\circ}C$ over reaction times of 5, 10, 30, and 60 min. Results: From this study, the highest glucose concentrations obtained from the dilute acid (DA) pretreated cobs, stalks, and leaves were 18.4 g/L (66.8% glucose yield), 16.2 g/L (64.1% glucose yield), and 11.0 g/L (49.5% glucose yield), respectively. The optimal pretreatment settings needed to obtain these yields from the DA pretreated samples were at a temperature of $160^{\circ}C$ over an incubation time of 30 min. The highest glucose concentrations obtained from the alkaline (AL) pretreated cobs, stalks, and leaves were 24.7 g/L (81.73% glucose yield), 21.3 g/L (81.23% glucose yield), and 15.0 g/L (51.92% glucose yield), respectively. To be able to achieve these yields, the optimal pretreatment settings for the cobs and stalks were $140^{\circ}C$ and for a retention time of 30 min, while the leaves require optimal conditions of $140^{\circ}C$ and for a retention time of 60 min. Conclusions: The study recommends that the leaves could be left on the field during harvesting since the recovery of glucose from the pretreated cobs and stalks is higher.

• Journal of Microbiology and Biotechnology
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• 제10권1호
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• pp.69-74
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• 2000

The medium for erythritol production by Torula sp. in a 500-ml baffled flask was optimized to be 300 g/I sucrose, 10 g/I yeast extract, 3 g/I $KH_2PO_4$, and 10 mg/I $CuSO_4{\cdot}5H_2O{\;}at{\;}34^{\circ}C$ with initial pH of 5.5. Using this optimal medium, erythritol of 166 g/I was obtained after 140 h of cultivation, corresponding to 55.3% of the erythritol yield from sucrose with a productivity of 1.11 g/I/h. Optimal concentrations of carbbon and nitrogen sources in a fermentor were higher than that in a flask due to the higher oxygen supply of the fermentor. Employing the medium containing 300 g/I or 400 g/I sucrose for the determination of optimal C/N ratio, the C/N ratio was found to be more important than the nitrogen concentration for effective erythritol production, The optimal ratio of yeast extract to sucrose (g/g) was 20. The yield and productivity of erythritol were maximal in the medium containing 400 g/I sucrose and 20 g/I yeast extract. when dissolved oxygen in the culture was increased, the cell mass increased but the erythritol production was manimal in the range of 5 to 10% of dissolved oxygen. Under the optimal the rane of 5 to 10% of dissolved oxygen. Under the optimal culture condition of the fermentor, a final erythritol concentration of 200 gI was obtained after 120 h with a yield of 50% and the productivity was 1.67 g/I/h. The yield was the highest among erythritol-producting microorganisms

• 한국작물학회지
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• 제69권1호
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• pp.61-69
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• 2024

남부지방(진주)에서 콩 생태형에 따라 적기파종 이후 파종 시기를 달리하였을 때 온도와 일장이 생육일수 및 수량에 미치는 영향을 조사한 결과는 다음과 같다. 1. 적기파종 이후 파종시기를 달리하여 파종하였을 때 모든 생태형에서 출현일, 개화소요일수, 전체 생육일수는 단축되었다. 2. 일장과 온도가 생육일수에 미치는 영향을 다중회귀분석으로 분석한 결과 파종~개화기까지 소요일수는 일장과 온도 모두 정의 상관이였고, 개화기~수확기까지 소요일수는 일장은 정의 상관, 온도는 부의 상관이 있었다. 3. 추정 회귀모형은 파종~개화까지 소요일수(Y) = 3.177 + (0.030 × (누적일장 + 적산온도)), 개화기~수확기까지 소요일수는 (Y) = 20.945 + (0.021 × (누적일장+적산온도))인 것으로 나타났다. 4. 수량은 적기파종에서 가장 높았고 적기파종 이후 늦게 파종할수록 수량이 급격히 감소하여 조생종은 7월 20일, 중만생종은 7월 10일 이전까지는 파종을 해야 급격한 수량감소를 피할 수 있을 것으로 보인다.

• 한국토양비료학회지
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• 제49권6호
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• pp.699-704
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• 2016

An estimation of optimal requirement of additional N by cropping pattern and growth stage is very important for greenhouse watermelon. The objectives of this study were to estimate an amount of optimal additional N based on growth, N uptake and yield of watermelon. In order to achieve these goals, we performed the study at farmer's greenhouse with a fertigation system and watermelon was cultivated three times (spring, summer and autumn) in 2015. The levels of additional N were set up with x0.5, x0.75, x1.0 and x1.5 of the $NO_3$-N-based soil-testing N supply for watermelon cultivation. The trends of growth and N uptake of watermelon markedly differed from cropping pattern; spring (sigmoid), summer and autumn (linear). The yield of watermelon was the highest at summer season and followed by autumn and spring. Also, the x1.5N showed a significantly higher yield compared to other N treatments. On the basis of growth, N uptake and yield of watermelon, we estimated an optimal level of additional N by cropping pattern and growth stage as follows; 1) spring (transplanting ~ 6 WAT : 6 ~ 14 WAT : 14 ~ harvest = 5 : 90 : 5%), summer (transplanting ~ 4 WAT : 4 ~ 8 WAT : 8 ~ harvest = 25 : 50 : 25%) and autumn (transplanting ~ 4 WAT : 4 ~ harvesting : 50 : 50%). In conclusion, nutrient management, especially N, based on cropping pattern and growth stage was effective for favorable growth and yield of watermelon.