• Fisheries and Aquatic Sciences
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• 제26권5호
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• pp.305-317
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• 2023

Ethiopia is branded as the Water Tower of Africa because of its abundant inland water bodies that may be used sustainably to boost the economy. This review article's goal is to examine the current status and future potential of Ethiopia's fisheries, with a special focus on reservoirs. There are 200 known fish species (194 native, 40 endemic, and 11 exotic) in in Ethiopia's inland water. Ethiopia's fish production has increased by a factor of more than five in the past three decades (3,500 tons in 1983 to 15,681 tons in 2000 and 18,058 tons in 2010). However, fish produced in reservoirs is too low (8,059 t/year). The current fish harvests from reservoirs are significantly below the predicted potential yield, accounting for only 35% of the calculated fish production capacity. In this review, 14 potential reserves were revealed. A total of 48 fish species have been reported in these, of which 26 species (or around 54%) are present in Alwero reservoir. 19 of the 48 species that have been officially recognized belong to the Cyprinidae family and made up nearly 40% of the fish population in Ethiopian reservoirs. There has been, however, a decline in the productivity of Ethiopia's reservoir fish. Hence, actively start fishing in the numerous reservoirs that have been neglected yet, link the potential of fisheries and the benefits of the fish farming supply chain, let's begin building several other reservoirs similar to the Grand Ethiopian Renaissance Dam and beginning mechanized-based fish harvesting.

• 한국토양비료학회지
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• 제49권6호
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• pp.682-688
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• 2016

Food waste has recognized one of useful sources for potentially agricultural application to supply organic matter and nutrients in arable soil. However, there was little information on application of food waste compost related to the maturity and NaCl content in arable soil. This study evaluated the effect of food waste compost application on yield and fertility in soil under flooding and upland condition. The yields in rice and pepper cultivation decreased with increasing the rate of food waste compost application in soil (p<0.05). Maximum yields of rice ($49.0g\;plant^{-1}$) and pepper ($204g\;plant^{-1}$) were shown at 10 and $30Mg\;ha^{-1}$ of food waste compost application, respectively. The N, P, and K contents in grain and plant residues increased by the application of food waste compost, there was no difference on Na/K ratio in plant tissue among the treatments. Application of food waste compost resulted in the increase of pH, EC, TC, available P contents in soil after crop harvest, especially, which was shown the increase of the CEC and exchangeable sodium percentage (ESP) contents in irrespective of water condition. In conclusion, application of food waste compost in soil was effective on the supply of the organic matter and nutrient. However, it might need caution to apply food waste compost for sustainable productivity in arable soil because of potential Na accumulation.

• 한국지형학회지
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• 제28권1호
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• pp.13-33
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• 2021

Successful sediment management at the watershed scale requires an understanding of the erosion, transport and sedimentation processes at the specific site scale. However, studies on the sediment runoff characteristics in a small uppermost watershed, which serves as a sediment supply function, are very rare. Therefore, this study attempted to investigate the fluctuations in major sediment supply areas and sediment runoff in the uppermost mountain small watershed, and for this purpose, ArcSWAT (Soil and Water Assessment Tools with GIS interface) was applied to the Woldong reservoir catchment located in Gosam-myeon, Anseong-si, Gyeonggi-do. The model results were manually calibrated using the monitoring data of the Woldong reservoir sedimentation rate from 2005 to 2007. It was estimated that annual average of 34.4 tons/year of sediment was discharged from the Woldong reservoir basin. This estimate almost coincided with the monitoring data of the Woldong reservoir during the low flow period but tended to be somewhat underestimated during the high flow period. Although the SWAT model does not fully reflect the erosion process of gully and in-channel, this underestimation is probably due to the spatial connectivity of sediment transport and the storage and reactivation of the sediment being transported. Most of the forested hillslopes with a well-developed organic horizon were evaluated as having a low risk of erosion, while the places with the highest risk of erosion were predicted to be distributed in the logged area with some weeds or shrubs (classified as pasture) with relatively steeper slopes, and in the bare land. The results of this study are expected to be useful in developing strategies for sediment control and reservoir management.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2011년도 학술발표회
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• pp.13-13
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• 2011

The Rio Grande Compact Commission, in collaboration with local water management entities, water users and universities established a three state Rio Grande The Rio Grande Compact Commission, in collaboration with local water management entities, water users and universities established a three state Rio Grande Salinity Management Program. The objectives of the Rio Grande Project Salinity Management Program are to reduce salinity concentrations, loading, and salinity impacts in the Rio Grande basin for the 270 mile river reach from San Acacia, New Mexico to Fort Quitman, Texasto increase usable water supplies for agricultural, urban, and environmental purposes. The focus of this first phase of the program is the development of baseline salinity and hydrologic information and a preliminary assessment of the economic impacts of salinity. An assessment of the economic impacts of salinity in this region was conducted by scientists at Texas A&M University's AgriLife Research Center at El Paso and New Mexico State University. Economic damages attributable to high salinity of Rio Grandewater were estimated for residential, agricultural, municipal, and industrial uses. The major impact issues addressed were: who is being affected the types of economic impacts the magnitude of economic damages overall and by user category and identification of threshold-effect levels for different types of water use. Salinity concentrations in this 270 mile reach of the river typically range from 480 ppm to 1,200 ppm, but can exceed 3,000 ppm in the lower section of this reach. Economic impacts include reductions in agricultural yields, reduced water appliance life, equipment replacement costs, and increased water supply costs. This preliminary economic assessment indicates annual damages of $10.5 million from increased water salinity. Under current water uses, municipal and industrial uses account for 75% of the total estimated impacts. However, agricultural impacts are based on current crop pattern yield reductions and, salinity leaching requirements and do not account for the impacts of reduced revenue from having to grow salinity tolerant, lower value crops. Actual damages are anticipated to be significantly higher with the inclusion of these additional agricultural impacts plus the future impacts from the growing population in the region. A more comprehensive economic analysis is planned for the second phase of this program. Results of the economic analysis are being used to determine the feasiblity of salinity control alternatives and what salinity reduction control measures will be pursued.

• Asian-Australasian Journal of Animal Sciences
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• 제23권3호
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• pp.372-378
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• 2010

The objective of this study was to investigate the effects of an oral drench of propylene glycol (PG) on milk production, serum metabolites and reproductive performance during the transition period of animals. Twenty-four 2-3 multiparous Holstein cows (average body weight 565 kg, body condition score about 3.6, at the $9^{th}$ month of gestation) were selected, blocked, and then randomly assigned into a PG and a control group. The control and the PG group cows were orally drenched with water or 50 ml sugarcane molasses mixed with 500 ml PG from 7 days pre-partum to 30 days post-partum, respectively. Experimental results indicated that the oral drench PG had no effect on dry matter intake (DMI). The milk yield of the PG group was significantly higher than that of the control group (p<0.05), whereas milk fat content, milk protein and somatic cell counts (SCC) were not significantly different between groups. Concentration of plasma glucose in the PG group was significantly higher than that of the control group (p<0.05). Conversely, the concentrations of non-esterified fatty acids (NEFA), and blood urea nitrogen (BUN) in the PG group were lower than those of the control group (p<0.05). Concentrations of insulin and ketone bodies were not significantly difference between groups. Body condition score (BCS) in the PG group was significantly higher than that of the control group (p<0.05). In reproductive performance there was no difference between groups. The experimental results indicate that supplementation of PG during the transition period of dairy cows can supply energy rapidly, resulting in reduced catabolism of body tissue and increased milk yield.

• 조명전기설비학회논문지
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• 제23권5호
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• pp.80-87
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• 2009

최근 오존은 그 효용성을 인정받아 다양한 분야에서 사용되고 있으며, 그 수요 또한 계속 증가하는 추세이다. 이에 다양한 종류의 오존발생기가 연구되고 있다. 본 연구는 실내공기와 상 하수도의 수질개선을 위하여 cascade형 평판전각 오존발생기(plate-type ozonizer : PTO)를 개발하여 그 특성을 조사한 논문이다. 평판전극의 크기, 개수 및 배치에 따라 4가지 형태의 오존발생기를 설계하였다. 각 형태의 오존발생기의 방전 면적은 22,400[$mm^2$]로 동일하며 방전전력은 최대 40[W]이다. 각 오존발생기의 오존생성량, 오존생성농도, 오존생성수율 특성을 연구한 결과, 8개의 평판전극이 cascade형으로 배치된 오존발생기(PTO-4)의 오존생성특성이 가장 우수하게 나타났다.

• 한국작물학회:학술대회논문집
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• 한국작물학회 1998년도 21세기 한반도 농업전망과 대책(한국작물학회.한국육종학회 공동주관 심포지움 회보)
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• pp.210-232
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• 1998

Tong-il, the high-yielding rice variety bred on early 1970, effected a turning point in modern rice production in Korea. As rice production reached the highest record yield in 1978 with HYV, Korea achieved self-sufficiency in domestic supply of rice (or the first time in (her own) history, HYV required high input of fertilizers and pesticides for proving its yielding ability and needed new techniques such as early nursery-planting to prevent chilling damage. But, farm economy did not follow the successful achievement of rice production because of increased farming cost and inflation.'Tong-il variety has been replaced by new high-yielding Japonica varieties from 1980 when record-low-temperature during summer months had persisted. Also, the cooked rice of Tong-il variety did not agree with the appetite of Korean people. Though the hectarage of Tong-il rice did reduce, farmers applied the same high-input cultural techniques for new Japonica cultivars as did for Tong-il variety. Heavy application of nitrogen fertilizer contaminated surface and ground water with nitrate ions while phosphorous fertilizer was blamed for algae pollution. Frequent spray of pesticide and herbicide reduced significantly the biotic population in paddy ecosystems including insects and soil microorganisms. The new technologies of the 21st century must be directed to produce safe food, to save natural resources, and to preserve a clean environment for human welfare. We need low-input sustainable farming techniques to provide high-yielding crops and to preserve a healthy ecosystem.

• 한국지형학회지
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• 제20권1호
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• pp.75-83
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• 2013

해안지역의 인위적 간섭은 토사의 생산 및 유출에 의해 지형적인 변동을 유발한다. 더욱이 해안변동을 안정화시키기 위한 구조물의 설치가 다른 지역의 지형을 변화시키는 요인이 되기도 한다. 그러나 대부분 해안지역에 대한 토사 유출자료는 구축되어 있지 않은 실정이다. 본 연구는 장기적인 해안변동 경향, 해안변동의 주요 인자인 토사유출의 정량적인 평가 방안, 그리고 이를 고려한 접속도로의 설계하중에 영향을 미치는 요소에 대해 적절한 방향을 제시하고자 한다.

• 청정기술
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• 제20권1호
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• pp.57-63
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• 2014

본 연구에서는 합성천연가스(synthetic natural gas, SNG)를 생산하기 위한 공정 개발을 위해 $H_2/CO$ 비가 낮은 합성가스를 이용하여 스팀과 함께 메탄화 반응을 수행하였다. 본 실험과 같은 조건에서는 수성가스 전환반응과 메탄화 반응이 동시에 일어나며, 스팀양이 적을 경우 촉매의 비활성화가 발생할 수 있다. 때문에, 스팀 양에 대한 반응특성을 수행하였으며, 더불어 고농도의 $CO_2$가 함유된 합성가스에 대한 메탄화 반응특성도 함께 고찰하였다. 그 결과, 스팀의 공급으로 인하여 촉매 층내의 온도를 낮출 수 있었으며, 메탄화 반응과 수성가스전환반응이 동시에 일어났음을 확인할 수 있었다. 고농도의 $CO_2$가 함유된 합성가스의 메탄화 반응에서는 조금 낮은 메탄 수율을 보였지만, 장기운전(1,000 h) 결과로부터 본 연구에서 수행한 합성가스의 조건을 SNG 공정에 적용이 가능할 것으로 확인되었다.

• 한국작물학회지
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• 제27권4호
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• pp.296-313
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• 1982

At a time when world population and food supply are in a delicate balance, it is essential that we look at factors to improve this balance. We can alter the environment to better fit the plant's needs, or we can alter the plant to better fit the environment. Improved technology has allowed us to increase the yield level. For moderately detrimental weather events technology has generally decreased the yield variation, yet for major weather disasters the variation has increased. We have raised the upper level, but zero is still the bottom level. As we concentrate the production of particular crops into limited areas where the environment is closest to optimum, we may be increasing the risk of a major weather related disaster. We need to evaluate the degree of variability of different crops, and how weather and technology can interact to affect it. The natural limits of crop production are imposed by important ecological factors. Production is a function of the climate, the soil, and the crop and all activities related to them. In looking at the environment of a crop we must recognize these are individuals, populations and ecosystems. Under intensive agriculture we try to limit the competition to one desired species. The environment is made up of a complex of factors; radiation, moisture, temperature and wind, among others. Plant response to the environment is due to the interaction of all of these factors, yet in attempting to understand them we often examine each factor individually. Variation in crop yields is primarily a function of limiting environmental parameters. Various weather parameters will be discussed, with emphasis placed on how they impact on crop production. Although solar radiation is a driving force in crop production, it often shows little relationship to yield variation. Water may enter into crop production as both a limiting and excessive factor. The effects of moisture deficiency have received much more attention than moisture excess. In many areas of the world, a very significant portion of yield variation is due to variation in the moisture factor. Temperature imposes limits on where crops can be grown, and the type of crop that can be grown in an area. High temperature effects are often combined with deficient moisture effects. Cool temperatures determine the limits in which crops can be grown. Growing degree units, or heat accumulations, have often been used as a means of explaining many temperature effects. Methods for explaining chilling effects are more limited.