• Asian-Australasian Journal of Animal Sciences
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• 제14권4호
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• pp.491-495
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• 2001

The behaviour of 5 Jersey and 5 Guernsey heifers, grazing on natural vegetation in a sub-humid tropical environment in Kenya, was studied during the dry (January and February) and wet (April and May) seasons in 1999. The heifers grazed for 12 hours daily in both seasons. Observations on feeding, standing, lying and ruminating were done chronometrically, at five-minute intervals, between 0600 and 1800 h. During the dry season, the average feeding, standing, lying and ruminating times per 12 h period for Jerseys was 8.0, 3.13, 0.87, and 1.40 respectively, while those for Guernseys were 8.6, 3.26, 0.4, and 1.35 respectively. In the wet (green) season, the mean feeding, standing, lying and ruminating times for Jerseys were found to be 7.54, 3.07, 1.39, and 1.27 respectively, and for Guernseys were 8.42, 3.10, 0.48, and 0.44 respectively. In both seasons Guernseys spent more time feeding (p<0.05) in comparison with the Jerseys. It was also observed that lying occurred more often in Jerseys than the Guernseys (p<0.05) in both seasons. During the wet season, Jerseys ruminated longer (p<0.05) than the Guernseys. The health status of the animals was determined by examining the respiratory frequency, heart rate, rectal temperature, haemoglobin erythrocytes and leucocytes of the experimental animals. All the clinical and physiological parameters were within the normal physiological range of healthy cattle. It was concluded that there are differences in grazing behaviour between Jerseys and Guernseys in the sub-humid tropical environment of Kenya and Jerseys seem to be more adapted to the tropical climatic conditions.

• Asian-Australasian Journal of Animal Sciences
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• 제17권12호
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• pp.1663-1668
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• 2004

This study was carried out to evaluate the potential nutritive value of commonly found grasses collected at native pasture in West Sumatra, Indonesia during dry and rainy seasons. Variables measured included chemical composition, in vitro digestibility, concentration of Ca, P and Mg, gas production and metabolizable energy (ME) content of the grasses. The results showed that species and season had significant effect on chemical composition and mineral concentration. Crude protein content in the dry season ranged from 6.5% (B. decumbens) to 14.4% (P. maximum) and increased slightly from 7.8% (B. decumbens) to 14. 8% (A. compressus) in the rainy season. Data on fiber fraction showed that grass contained more NDF, ADF and ADL in dry season than in rainy season. Data on mineral concentration showed that C. plectostachyus and P. maximum in dry season had higher Ca than those of other species, while in rainy season P. maximum had highest Ca concentration. In dry season, the DMD varied from 50. 4% (P.purpuphoides) to 59.1% (P. purpureum), while in rainy season ranged from 50.3% (A. gayanus) to 61.8% (P. purpureum). The potential and rate of gas production were significantly (p<0.05) affected by species and season. During dry season, potential of gas production ranged from 21.8 ml/200 mg (A. compressus) to 45.1 ml/200 mg (C. plectostachyus), while in rainy season it varied from 35.6 ml/200 mg (A. gayanus) to 47.5 ml/200 mg (P. purpureum). ME content of grasses varied from 6.0 to 8.3 MJ/kg in dry season and increased slightly from 6.4 to 8.6 MJ/kg in rainy season. Both in dry and rainy seasons, the highest ME content was occurred in P. purpureum and C. plectostachyus. In conclusion, nutritive value of the observed grasses in West Sumatra, Indonesia was relatively higher during rainy season compared with dry season. Pennisetum purpureum and Cynodon plectostachyus had the best nutritive value in both dry and rainy seasons.

• 대한환경공학회지
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• 제27권3호
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• pp.262-272
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• 2005

본 연구는 하구호 수질개선을 위한 유입하천정화 시설의 기초설계 자료를 마련하기 위한 일환으로 시작되었다. 조사대상 하천은 삽교호 유입 국가하천으로 도시관통 하천(곡교)과 농경지 관통하천(무한, 삽교)이었다. 3년 동안의 장기적인 수질관측결과 시기적으로 큰 변화를 나타내었다. 도시지역이나 농경지를 관통하는 하천에서 유량이 증가할수록 질소농도는 뚜렷이 감소하였다. 인 농도는 도시하천의 경우에는 질소와 마찬가지의 변화특성을 나타내었으나 반면에 농경지 유역하천의 경우에는 유량이 영향이 상대적으로 적었지만 유량이 크게 증가할 경우 오히려 크게 증가하였다. 그 이유는 강우에 따른 유량증가시 도시지역이나 농경지를 흐르는 하천수의 부유물질 농도는 크게 증가하지만 유출되는 부유물질의 화학적 특성이 전혀 다르기 때문으로 판단된다. 용존성 질소(dissolved-TN)는 대상하천에서 총질소의 약 $40{\sim}60%$를 차지하였으며 총인의 경우는 약 35% 가량이 용존성 인(dissolved-TP) 상태로 존재하였다. 하구호인 삽교호의 3개 유입하천에 대한 대표수질은 건기와 우기로 구분하여 결정하는 것이 타당하며, 대표수질 항목으로는 측정오차가 적고 유량변동에 따른 수질변화 특성을 가장 잘 표현하고 있는 TDS와 SS를 이용하는 것이 바람직할 것으로 사료된다. TDS는 건기의 총질소 농도 증가를 반영하며, SS는 우기의 총인 농도 증가를 설명하는데 효과적이다. 본 논문에서 제시된 누적확률그래프는 하천정화시설의 설계목적으로 다른 유역의 하천수질을 비교 평가하는데 유용하게 사용될 수 있을 것으로 사료된다.

• 한국대기환경학회지
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• 제17권1호
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• pp.19-29
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• 2001

Atmospheric concentrations of acidic pollutant were measured by the 4 stage filter pak method at Chunchon and by the 3 stage filter pack method at Seoul and Anmyon-do from January to December 1998. The sample was collected for 24 hours on every Wednesday. Concentrations of particulate matters were highest at Anmyon-do. The particulate concentration was much higher during the warm season than other seasons. While the particulate concentration was higher during the warm season, the concentration of gaseous matter was higher in winter. Dry deposition flux was calculated by using reported deposition velocities and concentration of pollutants measured in this study. The dry deposition velocities used in this study for SO$_2$, SO$_{4}^{2}$, HNO$_3$,NO$_{3}^{-}$ and NH$_3$ were 0.29, 0.15, 2.08( 2.13 only for Anmyon-do), 0.20 and 1.00cm/sec, respectively. At Chunchon, annual sulfur flux originated from dry deposition was 384 kg/$textrm{km}^2$, and the flux from wet deposition was 782kg/$textrm{km}^2$. Dry deposition of sulfur was 33% of total sulfur deposition. The annual nitrogen flux originated from dry deposition was 1,892kg/$textrm{km}^2$. And the flux from wet deposition was 1,066kg/$textrm{km}^2$. Dry deposition of nitrogen was 64% of total nitrogen deposition. Dry deposition as well as wet deposition have to be considerd in the study on acidification of environment such as soil or watershed.

• Journal of Ecology and Environment
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• 제43권4호
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• pp.376-384
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• 2019

Background: Nutrient release during litter decomposition was investigated in Vitex doniana, Terminalia avecinioides, Sarcocephallus latifolius, and Parinari curatellifolius in Makurdi, Benue State Nigeria (January 10 to March 10 and from June 10 to August 10, 2016). Leaf decomposition was measured as loss in mass of litter over time using the decay model W_t/W₀ = e-^{kd t}, while $Kd=-{\frac{1}{t}}In({\frac{Wt}{W0}})$ was used to evaluate decomposition rate. Time taken for half of litter to decompose was measured using T₅₀ = ln ²/k; while nutrient accumulation index was evaluated as $NAI=(\frac{{\omega}t\;Xt}{{\omega}oXo})$. Results: Average mass of litter remaining after exposure ranged from 96.15 g, (V. doniana) to 78.11 g, (S. lafolius) in dry (November to March) and wet (April to October) seasons. Decomposition rate was averagely faster in the wet season (0.0030) than in the dry season (0.0022) with P. curatellifolius (0.0028) and T. avecinioides (0.0039) having the fastest decomposition rates in dry and wet seasons. Mean residence time (days) ranged from 929 to 356, while the time (days) for half the original mass to decompose ranged from 622 to 201 (dry and wet seasons). ANOVA revealed highly significant differences (p < 0.01) in decomposition rates and exposure time (days) and a significant interaction (p < 0.05) between species and exposure time in both seasons. Conclusion: Slow decomposition in the plant leaves implied carbon retention in the ecosystem and slow release of CO₂ back to the atmosphere, while nitrogen was mineralized in both seasons. The plants therefore showed effectiveness in nutrient cycling and support productivity in the ecosystem.

• 한국농공학회지
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• 제26권3호
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• pp.46-58
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• 1984

This study was carried out to investigate the compressive strength and the other effects varying to seasons and curing days on the wet curing conditions of the plain concrete. The results obtained are summarized as follows; 1. The longer the wet curing days and the higher the temperature, the greater the compressive strength was expected. 2.。$_2$8, compressive strength of concrete at 28 days under the dry curing conditions showed a range in 64-76% of that under the wet curing conditions. 3. The seasonal variations in the compressive strength under the wet curing showed in order of summer>spring=autumn>winter, and that under the dry curing were in order of spring ≒autumn> summer> winter. 4. In order to obtain 90% of the design compressive strength, 7 days in spring or autumn and 2 weeks of the wet curing in summer were required. 5. The compressive strength of concrete under the wet curing by using wet straw bag cover was almost the same as that of water curing method. 6. Under the wet curing conditions, the higher the temperature, the greater the effect of the curing of concrete was obtained, however, the compressive strength of concrete was decreased under relatively higher (over 15$^{\circ}$ C) and lower temperature (below 4$^{\circ}$C). 7. Freezing damage was occured when temperature was below 0$^{\circ}$ C and humidity was relatively high. 8. A considerable differnce between estimation of $^{\circ}$$_2$8 from $^{\circ}$7 and measured one was appeared in case of the dry curing conditions. Oregon formula was appeared to be acceptable under the wet curing conditions. 9. In relationship between $^{\circ}$$_2$8 and $^{\circ}$7~, $^{\circ}$28=1. 52 $^{\circ}$7 under the wet curing conditions except winter season, and $^{\circ}$$_2$8 =(1.39-1, 48)$^{\circ}$7 under the dry curing conditions were shown.

• 대한지리학회지
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• 제44권2호
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• pp.105-121
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• 2009

지형 굴곡이 심한 하와이 화산섬의 경우, 측후소 분포가 매우 제한적이어서 공식적인 기온 분포도가 작성되지 못하고 있는 실정이다. 본 연구에서는 이러한 기온 지도화의 문제점을 해결하는 방법으로 위성기반의 지표온도 자료로부터 기온추정치를 추출하여 내삽법에 필요한 입력자료로 사용하였다. 추출된 온도값을 표본값으로하여 거리 역비례 가중치법(IDW)과 공동크리깅 (cokriging)을 적용하여 기온추정치를 지도화하였다. 기온과 고도값을 함께 이용한 cokriging이 IDW에 비해 크게 향상된 추정 오차값을 나타내었다. Cokriging은 주 변수와 고도와 같은 추가 변수 간의 상관관계가 유의하게 나타날 때 효과적으로 사용되는 내삽법이지만, 내삽 정확도는 계절적인 기상조건에 민감하게 영향받는 것으로 조사되었다. 강수량이 크게 증가하는 우기에는 건기에 비해 공간적인 기온변화가 크며, 이에 따라 기온 추정 오차값도 우기에 높게 나타났다.

• Asian-Australasian Journal of Animal Sciences
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• 제7권3호
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• pp.325-333
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• 1994

This study was undertaken at Gowa, South Sulawesi, Indonesia as part of a larger forage genetic resource evaluation project. The experimental program consisted of a field experiment where grasses and legume species were grown in monocultures and the yield, N content and rumen bag digestibility using goats were measured. The field experiment was conducted from December 1985 to October 1986. Eight species of legumes (Desmodium heterophyllum cv. John-stone, Desmodium triflorum from Gowa, South Sulawesi, Arachis sp. from Maiwa, South Sulawesi, Clitoria ternalea CPI 50973, Macroptilium atropurpureum ev. Siratro, Neonotonia wightii cv. Tinaroo, Centrosema pubescens CPI 58575, Centrosema plumeri CPI 58568) were grown as monocultures. After establishment all plants were cut to a uniform height of 5 cm, and subsequent cuts were made on regrowth after 14, 28, 42, and 56 days (cycle 1). Cycle 2 commenced towards the end of the wet season and continued for 157 days into the dry season. The highest yielding legumes were C. ternatea in the wet season and Arachis sp. in the dry season. The mean rumen bag dry matter digestibility (RBDMD) of legumes of 67.6% for leaf material (averaged over all cycles and ages) was 7.6% higher than for stem material. The RBDMD of Arachis was significantly higher than all other species. The RBDMD of all legumes declined with age. Calculation of yield of digestible DM (yield $\times$ RBDMD) showed that Arachis sp. was the best legume. The combination of plant "quality" with yield measures is a valuable adjunct to routine agronomic survey procedures in plant evaluation programs. Arachis sp. appears to offer considerable promise and should be more widely evaluated.

• Environmental Engineering Research
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• 제21권1호
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• pp.84-90
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• 2016

Regionally the lowest average concentration of TOC was observed with 0.66 mg/L in Nakdong river, while the highest concentration of TOC was observed with 0.91 mg/L in Yeongsan river. The average concentration of TOC for national water quality monitoring site showed that the lowest average concentration of TOC was 1.58 mg/L in Han river, while the highest concentration of TOC was 3.37 mg/L in Yeongsan river. Seasonally, the average concentration of TOC at six upstream sites showed 0.77 mg/L and 0.56 mg/L, 0.69 mg/L and 0.63 mg/L, 0.80 mg/L and 0.73 mg/L, and 1.21 mg/L and 0.68 mg/L between wet season and dry season in Han river, Nakdong river, Gem river and Yeongsan river, respectively. For the national water quality site, the average concentration of TOC between wet season and dry season was 1.70 mg/L and 1.45 mg/L in Han river, 2.01 mg/L and 1.75 mg/L in Nakdong river, 2.01 mg/L and 1.60 mg/L in Gem river, and 3.75 mg/L and 3.00 mg/L in Yeongsan river. The distribution of TOC in upstream and national water quality monitoring sites on four major rivers have been influenced by seasonal and regional characteristics in Korea.

• Fisheries and Aquatic Sciences
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• 제26권8호
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• pp.482-490
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• 2023

Food and feeding habits of Labeobarbus intermedius were studied from the newly constructed Ribb Reservoir, Ethiopia during the dry (December-March) season and wet season (June-August) of 2021. The objective of the study was to determine the diet composition, seasonal variation, and ontogenetic dietary shift in the diets of the dominant cyprinid fish in Ribb Reservoir. In this study, frequency of occurrence and volumetric analysis methods were used to present the results. From a total of 203 fish samples, 132 (65%) guts contained food items. Macrophytes (29.4%), phytoplankton (27.2%), detritus (14.8%), and insects (13.6%) were the major food items in the diets volumetrically. During the dry season, L. intermedius was mainly dependent on phytoplankton (58.2%), insects (15.2%), and zooplankton (13.7%) volumetrically. Whereas, macrophytes (50.3%) and detritus (23.3%) were the dominant food items in the wet season. The frequency occurrence and volumetric contribution of the diets of L. intermedius varied significantly (χ² test, p < 0.05) between seasons. Schoener's diet overlap index revealed a slight ontogenetic dietary shift in the diets of L. intermedius. While insects, nematodes, and zooplankton were the main diets of small-sized L. intermedius, macrophytes and detritus were ingested by large-sized L. intermedius. Generally, L. intermedius fed both plant and animal-origin food items and is considered an omnivorous feeder in Ribb Reservoir.