• Asian-Australasian Journal of Animal Sciences
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• v.9 no.2
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• pp.181-187
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• 1996

About 8 million tons of straw (dry matter) become rotten during the monsoon(June to August) season in Bangladesh. The possibility of preserving straw with urea, under wet condition during dry period (December to May) and its utilization by cattle has been studied. Five tons of fresh and wet(600g DM/kg material) rice straw were preserved for six months, with 5% urea(W/W) in either dome or rectangular shaped heap without any polythene cover. The preservation quality, acceptability and nutritive value of preserved straw were then comparted with that of dry straw in growing cattle. In both types of heaps, straw was excellently preserved having strong ammonia smell,dark brown in colour with no fungal infestation. Urea preservation of straw increased its CP and ADF content. Preserved straw was readily accepted by the animals and they were healthy throughout the experimental period. Compared to dry straw, urea preserved straw had nonsignificantly higher rumen degradability, straw intgake and growth rate. Similarly, digestibilities of DM(p<0.01), OM(p<0.01) & ADF(p<0.01) were significantly higher in the preserved than the dry straw. It was concluded that wet straw with relatively lower moisture(400 to 500 g/kg straw) content can be readily preserved by using urea without being covered with polythene. Whether the same phenomenon occurs in the preservation of fresh and weet rice straw with relatively higher moisture(600 to 700 g/kg straw) content is yet to be determined.

• Journal of Korea Water Resources Association
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• v.51 no.spc
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• pp.1091-1103
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• 2018

Having knowledge regarding to which region is prone to drought or flood is a crucial issue in water resources planning and management. This could be more challenging when the occurrence of these hazards affected by climate change. In this study the future streamflow during the wet season (July to September) and dry season (October to March) for the twenty first century of South Korea was investigated. This study used the statistics of precipitation, maximum and minimum temperature of one global climate model (i.e., INMCM4) with 2 RCPs (RCP4.5 and RCP8.5) scenarios as inputs for The Precipitation-Runoff Modelling System (PRMS) model. The PRMS model was tested for the historical periods (1966-2016) and then the parameters of model were used to project the future changes of 5 large River basins in Korea for three future periods (2025s, 2055s, and 2085s) compared to the reference period (1976-2005). Then, the different responses in climate and streamflow projection during these two seasons (wet and dry) was investigated. The results showed that under INMCM4 scenario, the occurrence of drought in dry season is projected to be stronger in 2025s than 2055s from decreasing -7.23% (-7.06%) in 2025s to -3.81% (-0.71%) in 2055s for RCP4.5 (RCP8.5). Regarding to the far future (2085s), for RCP 4.5 is projected to increase streamflow in the northern part, and decrease streamflow in the southern part (-3.24%), however under RCP8.5 almost all basins are vulnerable to drought, especially in the southern part (-16.51%). Also, during the wet season both increasing (Almost in northern and western part) and decreasing (almost in the southern part) in streamflow relative to the reference period are projected for all periods and RCPs under INMCM4 scenario.

• Journal of The Korean Society of Agricultural Engineers
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• v.59 no.2
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• pp.91-99
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• 2017

The objective of this research was to investigate runoff characteristics of suspended solid (SS) and chemical oxygen demand (COD) from a paddy field watershed during storm events in the growing and non-growing seasons. Average of event mean concentration (EMC) of pollutants were 56.9 mg/L for SS and 23.9 mg/L for COD in the non-growing season and 50.3 mg/L for SS and 11.9 mg/L for COD in the growing season. The average EMC of SS in the study area was much lower than that in the uplands irrespective of cultivation, suggesting that paddy fields control soil erosion. This may be because flooding and wet soil in the growing season, and rice straw residue and stubble on the topsoil in the non-growing season reduce soil erosion. The changing tillage practice from fall tillage to spring tillage avoids soil erosion due to shortening of the tilled fallow period. However, the average EMC of COD in the non-growing season was about twice as much that in the growing season likely due to the runoff of organics like rice straw residues. The relationship between SS and COD loads and stormwater runoff volume was expressed by power function. The exponent for SS was higher than that for COD, suggesting that SS load increased with stormflow runoff more than COD load did. The mean SS and COD loads per storm during the non-growing season were much lower than those in the growing season, and therefore non-point source pollution in the growing season should be managed well.

• Journal of Korean Society on Water Environment
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• v.22 no.5
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• pp.887-894
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• 2006

Water quality in the Daecheong reservoir has been deteriorated by algal bloom every year. Algal bloom is propagated from eutrophicated tributary into the main body of the reservoir during the wet season. Nutrients from diffuse sources trigger the propagation of the algal bloom. This study is aimed to analyze relationship between the water current by the simulation and algae transport from the main body in the Daecheong reservoir including tributary where algal bloom has occurred seriously every year. Water quality model CE-QUAL-W2 was applied to analyze water movement in draught season (2001) and flooding season (2003). The result of simulation corresponded with the observed water elevation level, 63~80 m and showed stratification of the Daecheong reservoir. In the draught season, as velocity and direction off low in the reservoir was estimated to affect algae transport including nutrient supply from small tributary, algal blooms occurred in the stagnate zone of middle stream of the reservoir. On the other hand, in the flooding season, it was resulted in nutrient transport from upstream of main reservoir and nutrients were delivered up to downstream by fast water velocity. In result, algal blooms occurred in stagnate zone of reservoir downstream as the current of downstream was retarded according to dam outflow control.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.211-211
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• 2015

Mekong River is the world's $10^{th}$ longest river and runs through China's Yunnan province, Burma, Thailand, Laos, Cambodia and Vietnam. And Tonle Sap Lake, the largest fresh water body in Southeast Asia and the heart of Mekong River system, covers an area $2,500-3,000Km^2$ in dry season and $10,000-16,000Km^2$ in wet season. As previously noted, the water within Sap river flows from the Mekong River to Tonle Sap Lake in flood season (between June and October) and backward to Mekong River in dry season. Recently the flow regime of Sap River might be significantly affected by the development of large dams in upstream region of Mekong River. This paper aims at basic study about the large scale flood inundation of Cambodia using by CAESAR-Lisflood. CAESAR-Lisflood is a geomorphologic / Landscape evolution model that combines the Lisflood-FP 2d hydrodynamic flow model (Bates et al, 2010) with the CAESAR geomorphic model to simulate flow hydrograph and erosion/deposition in river catchments and reaches over time scales from hours to 1000's of years. This model is based on the simplified full Saint-Venant Equation so that it can simulate the interacted flow of between Mekong River and Tonle Sap Lake especially focusing on the flow direction change of Sap River by season.

• Journal of Environmental Science International
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• v.17 no.10
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• pp.1075-1080
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• 2008

The influence of the point source inflow on the water quality variation in the downstream of Hyeongsan River was investigated. As the results of seasonal variation, the pollutant concentrations of dry season were 1.5-4 times higher than those of wet season. The increase rate of $BOD_5$, $COD_{Mn}$, T-N, T-P due to point source were ranged to $8.1\sim42.6%$, $7.3\sim41.9%$ and $17.1\sim207%$ as the inflow of P1, P2 and P3, respectively. After P1, P2 and P3 inflow, the accumulated increase rate were 64.3%, 32.6%, 93.1% and 258.9% in $BOD_5$, $COD_{Mn}$, T-N, T-P, respectively. It was found that the influence of point source inflow on the water quality in the downstream of Hyeongsan River is severe.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.9
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• pp.1190-1197
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• 2010

The objective of the study was to determine the relationship between faecal egg counts and nutritionally-related blood metabolites in Nguni goats of South Africa. Body weights, body condition scores (BCS), FAMACHA scores, faecal and blood samples were collected from 96 Nguni castrates. Faecal samples were analysed using the modified McMaster technique for nematodes and the sedimentation method for trematodes. Blood was analysed for packed cell volume (PCV), glucose, cholesterol, total protein, albumin, urea and creatinine. Season had an effect on glucose, globulin, total protein, creatinine, PCV and faecal egg counts (FEC). Globulin, PCV, creatinine and FEC were significantly higher in the wet season compared to the dry season. A quadratic relationship existed between faecal egg count loads and BCS whilst negative linear relationships were observed between faecal egg counts and creatinine, albumin and cholesterol levels of Nguni goats.

• Fisheries and Aquatic Sciences
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• v.25 no.1
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• pp.20-30
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• 2022

The present study was carried out to investigate the food and feeding habits of Oreochromis niloticus in Lake Shala to manage this species in this high Soda Lake. Stomachs of 226 fish (65.9%) had different food items, while those of 117 fish (34.1%) were empty. Phytoplankton was the dominant food categories occurring in 90.3% of the stomachs estimated and contributed 75.5% of the total volume. Bacillariophyceae (Nitzschia, Anomoeoneis, Navicula and Melosira) were identified as the most desired phytoplankton item. The prey items of O. niloticus differed among size classes (ANOVA, p < 0.05). The main prey items were zooplankton by the smaller-size class, and phytoplankton in fish of the larger-size class. Seasonal variation in the diet composition was evident (t-test, p < 0.05) and zooplankton, chironomids, nematodes, fish scales and detritus were important during the wet season, while phytoplankton predominates during the dry season. This study concludes that O. niloticus had a phytoplanktivores feeding mainly on phytoplankton and their feeding habits influenced by season and fish size in Lake Shala.

• Korean Journal of Ecology and Environment
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• v.43 no.1
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• pp.35-43
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• 2010

Nutrient limitation and light limitation was examined for the Youngsan Lake by collecting chlorophyll $\alpha$ and other properties including light intensity, nutrient concentrations, pheopigment ratio monthly from March, 2003 to April, 2004 (except for November-January). Chlorophyll $\alpha$ was fractionated into net-(>$20\;{\mu}m$) and nano-size(<$20\;{\mu}$). Light and nutrient limitation index was calculated based on the equations incorporating the mechanisms of limitation of light and nutrients from the literature. Phytoplankton population (chlorophyll $\alpha$) was low during the wet season especially in August and increased in short-period during other seasons. Photoperiod was short during the wet season but long during the dry season. Nutrients such as phosphate and ammonium were rapidly increased in spring, 2004. Light limitation index was minimum (0.01) in August during the wet season and nutrient limitation index was relatively high (>0.4) except for May and September. Light limitation may affect phytoplankton growth rather than nutrient limitation considering that nutrient levels are high in the Youngsan Lake. Results of correlation analyses showed a negative correlation between light and nutrient limitation indices and net-pheopigment index, and a positive correlation between the indices and nano-pheopigment index. These results suggest that phytoplankton response to change of light and nutrient may be size-dependant.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.7
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• pp.951-955
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• 2001

The behaviour of 6 Toggenburg and 6 Saanen female goats, grazing on natural vegatation in a modified sub-humid tropical environment of Kenya, was studied during the dry (January and February) and wet (April and May) seasons in 1997. The two exotic breeds grazed for 12 h daily. Observation on feeding, standing, lying and ruminating was done chronometrically at five minute intervals between 0600 and 1800 h. These grazing times were based on the current practice of small holder farmers. During the dry period, the average feeding, standing, lying and ruminating time per 12 h period for Saanens was 5.63, 4.57, 1.80 and 1.50 h respectively while that for Toggenburgs was 7.26, 3.21, 1.53 and 1.96 h, respectively. In the wet(Green) season, the mean feeding, standing, lying and ruminating time for Saanens was found to be 5.08, 4.63, 2.29 and 0.72, respectively.Toggenburgs spent more time feeding (p<0.05) than Saanens in both seasons. It was also observed that standing occured more often in Saanens than the Toggenburgs in the dry season. During the wet period, Saanens ruminated significantly longer than the Toggenburgs. The health status of the animals was determined by analyzing the respiratory frequency, heart rate, rectal temperature, hemoglobin, erythrocytes and leucocytes of the experimental animals. All the clinical and physiological parameters were within the normal physiological range of healthy goats. It was concluded that differences in the grazing behaviour of Saanens and Toggenburgs in the modified tropical environment of Kenya, do exist.