• The Korean Journal of Ecology
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• 제25권5호
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• pp.359-364
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• 2002

시화지구 인공습지에 식재된 정수식물인 갈대(Phragmites australis)의 관리 방안을 모색하기 위해 갈대에 의한 질소 및 인 흡수 제거 양상과 갈대 생장과 관련된 토양 특성을 조사하였다. 습지 조성 초기에 갈대의 생장은 토양 염농도에 의해 저해된 것으로 나타났으며, 토양 유기물 함량은 갈대 비생육기 동안 고사체의 집적에 의해 증가하였지만, 서서히 분해되어 감소한 것으로 조사되었다. 갈대의 건물중과 질소 및 인 흡수량은 생장기인 여름과 가을에는 증가하였지만, 비생육기인 가을에는 감소하였다. 따라서 생장기 동안 갈대의 흡수에 의해 상당한 양의 질소와 인이 제거되었지만, 비생장기 동안 갈대 고사체의 형태로 토양에 환원되어 미생물의 분해에 의해 영양염류가 재방출될 가능성이 높은 것으로 판단되었다. 본 연구 결과에 의하면 인공습지 조성의 목적인 수질 정화와 생태공원으로서의 기능을 위해서는 갈대를 생육기간 중에 수확하는 방안을 적극적으로 모색해야 될 필요성이 있다.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제4권1호
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• pp.31-42
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• 2000

The dry deposition velocities and fluxes of air pollutants such as SO2(g), O3(g), HNO3(g), sub-micron particulates, NO3(s), and SO42-(s) were estimated according to local meteorological elements in the atmospheric boundary layer. The model used for these calculations was the multiple layer resistance model developed by Hicks et al.1). The meteorological data were recorded on an hourly basis from July, 1990 to June, 1991 at the Austin Cary forest site, near Gainesville FL. Weekly integrated samples of ambient dry deposition species were collected at the site using triple-fiter packs. For the study period, the annual average dry deposition velocities at this site were estimated as 0.87$\pm$0.07 cm/s for SO2(g), 0.65$\pm$0.11 cm/s for O3(g), 1.20$\pm$0.14cm/s for HNO3(g), 0.0045$\pm$0.0006 cm/s for sub-micron particulates, and 0.089$\pm$0.014 cm/s for NO3-(s) and SO42-(s). The trends observed in the daily mean deposition velocities were largely seasonal, indicated by larger deposition velocities for the summer season and smaller deposition velocities for the winter season. The monthly and weekly averaged values for the deposition velocities did not show large differences over the year yet did show a tendency of increased deposition velocities in the summer and decreased values in the winter. The annual mean concentrations of the air pollutants obtained by the triple filter pack every 7 days were 3.63$\pm$1.92 $\mu\textrm{g}$/m3 for SO42-, 2.00$\pm$1.22 $\mu\textrm{g}$/m-3 for SO2, 1.30$\pm$0.59 $\mu\textrm{g}$/m-3 for HNO3, and 0.704$\pm$0.419 $\mu\textrm{g}$/m3 for NO3-, respectively. The air pollutant with the largest deposition flux was SO2 followed by HNO3, SO42-(S), and NO3-(S) in order of their magnitude. The sulfur dioxide and NO3- deposition fluxes were higher in the winter than in the summer, and the nitric acid and sulfate deposition fluxes were high during the spring and summer.

• 한국지리정보학회지
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• 제14권3호
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• pp.150-162
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• 2011

우리나라에서는 최근 19년 동안에 연평균 448건의 산불이 발생하였다. 특히, 전체 산불발생건 수의 약 94%가 봄 가을철 건조계절에 동시다발적으로 빈번하게 발생하였다. 이는 국가적인 산림화재의 피해를 최소화하기 위해 산불을 효율적이고 체계적으로 관리하는 것이 필요하다. 본 연구에서는 최근 19년간 발생한 건조계절 산불을 1990년대와 2000년대로 나누어 순기에 따른 각 시군별 산불발생빈도의 시공간적 패턴을 GIS로 분석 후 1990년대 대비 2000년대의 순기별 산불발생빈도 변화 패턴을 비교 분석하였다. 분석 결과 1990년대와 2000년대에는 가장 높은 산불발생빈도를 나타낸 순기가 4월 초순으로 같았지만 이에 대한 지역별 산불발생빈도가 한반도 서쪽인 충청지역을 중심으로 대전에서 27건으로 가장 많이 증가하였고, 호남 및 인천지역에서 10건 이상 증가한 것으로 분석되었다. 그러나 강원 홍천에서는 4월 하순에 최대 12건이 감소한 것으로 나타났다. 본 연구를 통해 시기변화에 따라 이동하는 산불에 대한 지역별 맞춤형 산불방지대책 수립이 가능해질 것으로 판단된다.

• 한국잠사곤충학회지
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• 제29권1호
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• pp.1-6
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• 1987

발아기에 즈음하여 품종별로 뽕나무 동아의 수분율, 건물중, 전실소(T-N), P, K, Ca, Mg, B, Fe, Cu, Zn, Mn, 죽는율 등의 경시적 변화를 알기 위하여 올뽕계로 홍올뽕과 청올뽕, 중뽕계로 계량뽕과 청일뽕의 동아를 1986년 2월 28일부터 4월 28일까지 2개월간 일주일 간격으로 채취 분석한 결과, 다음과 같은 결과를 얻었다. 1. 뽕나무의 수분율은 초기 45% 내외에서 후기 65% 내외로 20%정도 증가하였으며, 홍올뽕이 가장 높았으며, 나머지 품종간에는 차가 인정되지 않았다. 2. 동아의 건물중은 올뽕계가 언제나 중뽕계보다 무거웠다. 올뽕계는 초기부터 건물중이 서서히 증가하다가 4월 18일 이후 급격히 증가하였으나, 중뽕계는 4월 12일까지 증가하지 않다가 그 후에야 완만히 증가하였다. 3. 초기에서 후기로 갈수록 증가하는 성분은 T-N, P, K, B, Fe, Cu, Zn 등이었으며, 변동이 없는 성분은 Ca, Mg이었고, Mn은 오히려 후기로 갈수록 서서히 감소하였다. 4. 홍올뽕에서는 T-N과 Mn은 다른 품종에서 보다 놀았으나, P, Ca, Fe, Cu 등은 낮았으며, 청일뽕은 T-N, Mg 및 Cu 등이 다른 품종에서 보다 낮았다. 5. 동아의 죽는 비율은 발아기가 가까워 올수록 증가하였고, 품종별로는 청올뽕이 가장 높았으며, 청일뽕과 개량뽕은 중간에서 서로 비슷하였으며, 홍올뽕은 현저히 낮았다.

• 한국수자원학회논문집
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• 제39권10호
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• pp.881-890
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• 2006

SWAT 모형을 이용하여 대전 3대 하천 유역의 수문 분석 및 도시화에 따른 영향을 평가하였다. 물수지 분석결과에 의하면, 전체적으로 총 유출량 중 지하수 유출량이 44%정도, 중간 유출량이 6% 그리고 지표유출량이 50%이다. 도시화 영향 분석 결과 전체적으로 1975년에서 2000년까지 갑천유역의 약 5%가량의 도시화는 총 유출량의 변화에 있어서는 현저한 차이를 보이지 않았으나, 도시화 율이 32%정도 증가한 소유역의 경우 유출 성분 분석에서 첨두 유량의 경우 $25{\sim}66%$의 증가를 보였고, 지하수 유출량의 경우 $68{\sim}73%$의 감소를 확인 할 수 있었다. 그리고 도시화의 영향으로 토양수분량은 건기를 제외한 모든 시기동안 감소한 반면 침투량은 모든 시기동안 감소하였다. 도시화의 영향은 강우량이 적고, 증발량이 많은 갈수년에 더 크게 나타났다. 이 결과로부터 도시화의 영향으로 풍수기 동안의 홍수피해 폰가 및 갈수기 동안의 하천의 건천화 문제를 유추 할 수 있을 것이다. 결론적으로 본 연구에서 수행한 수문분석 및 도시화 영향분석 결과는 향후 대천 3대 하천의 생태하천복원을 위한 물순환 정상화 대책마련 및 하천의 유량확보방안 마련을 위한 기초자료로 사용될 수 있을 것이다.

• 한국수자원학회논문집
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• 제54권spc1호
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• pp.1131-1141
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• 2021

본 연구에서는 국내 주요 댐 상류 유역을 대상으로 장기간 시단위 수문자료를 활용하여 실시간 댐 유입량 예측을 위한 인공신경망 모형의 선행 1, 3, 6시간별 예측유입량을 산정 및 평가하였다. 이를 위해, 각 유역별 15년의 시단위 강수 및 유입량 자료를 활용하였으며 연도별 평균 유입량을 고려하여 데이터세트를 구성하였다. 각 대상유역에 대한 선행시간별 예측 성능은 NSE 0.57~0.79 이상으로써 비교적 양호한 성능을 나타내었다. 유역면적이 클수록 이수기의 예측 성능이 낮은 것으로 확인되었으며 홍수기 예측성능과의 편차가 증가하는 것으로 확인되었다. 선행 6시간 예측에 대해 입력자료의 과거길이에 따른 성능 변화는 홍수기보다 이수기에서 큰 차이를 보이며 과거길이가 증가할수록 이수기의 성능이 향상되는 것으로 나타났다. 주요 홍수 사상에 대한 예측 수문곡선은 관측과 비교하여 수문곡선의 형태는 유사한 것으로 나타났다. 다만, 선행시간에 따라 첨두시간의 지연 및 유량의 과소 추정되는 경향이 있으며 이에 대한 개선이 필요함을 확인하였다.

• 한국작물학회지
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• 제35권2호
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• pp.156-164
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• 1990

A field experiment was conducted to study both the distribution characteristics of photosynthetically active radiation (PAR) in the soybean canopy and their relationships with dry matter production. The soybean cultivars 'Hwanggeumkong' and 'Paldalkong' were sown with the spaces of 60$\times$15cm and 30$\times$15cm at Suwon on May 20 and on June 20 in 1989. The ratio of PAR to the total shortwave radiation was estimated by the empirical equation derived from sunshine hours and direct incoming radiation. The functional relationships between the PAR interception and the leaf area index were expressed as a function of Beer's law. The extinction coefficients(k) in the functions ranged from 0.77 to 0.92. The values of k were greater at higher planting density, but they were affected neither by planting dates nor by varieties. The reflection ratio of PAR($\alpha$) was determined by the exponential function as below; $\alpha$=$\alpha$p-($\alpha$p-$\alpha$o) exp(-kㆍLAI) where $\alpha$p was the reflectance at the maximum LAI and $\alpha$o was that of the bare soil. The ap ranged from 0.025 to 0.035 and $\alpha$o ranged from 0.11 to 0.12, respectively. The reflected PAR ranged from 0.049 to 0.064 and the transmitted PAR ranged from 0.168 to 0.340 until maximum dry weights were observed. The slope from the linear regression of dry matter on absorbed PAR, conversion efficiency, ranged from 1.30 to 2.3g MJ$^{-1}$ during the growing season until maximum dry weight was reached. The total dry matter yield above ground (TDM) increased with the increases in the conversion efficiency. TDM was higher in Hwanggeumkong than Paldalkong and higher in the space of 30$\times$15cm than 60$\times$15cm, Paldalkong showed higher harvest index than Hwanggeumkong. than Hwanggeumkong.

• Asian-Australasian Journal of Animal Sciences
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• 제17권12호
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• pp.1689-1694
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• 2004

This study was conducted to develop a novel adjustment factors for 305 days using 138,103 lactation records and 1,770,764 daily records, which were based on environmental circumstances such as herd year, season, age at calving, dry period and lactating stages. The present study showed that the change of persistency of cows at the first parity from total lactacting characteristics was slowly processed, while it was rapidly changed in cows at the second parity stage. Particularly, there was an outstanding difference between the first and second parity cows. Milk yield and composition increased as the age at calving was increased. In addition, milk yield and composition were higher at the first parity on fall compared with others, and those were higher at the more than second parity on fall and winter compared with other parity stages and seasons. The cow of dry group was included into lactating records of more than second parity stage. The data indicated that optimal results arose from 45-70 days of dry period. Milk yield was decreased when dry period was longer or shorter than 45-70 days. The lactating days were divided into 17, 28 and 38 stages to compare the multiplicative correction factors. The factor was effective at 28 stages on the first parity. The total correlation coefficients were 0.93832, 0.95058 and 0.95076 at the present correction factor, 17 stage and 28 stage, respectively. At second parity, the factor was higher in dry group 1 and 3 at 17 stage, and it was higher in dry group 2 at 28 stage compared with others. Therefore, the present study showed that the percent squared bias (PSB), which was calculated from the novel correction factor, was better than previously used correction factors. Also, the present study indicated that the bias of the novel correction factor was improved, and this factor could be more accurate compared with others.

• Asian-Australasian Journal of Animal Sciences
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• 제16권3호
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• pp.384-388
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• 2003

Twenty yearling lambs of Southeast Nigeria dwarf, liveweight ($18{\pm}1.9 kg$) were grouped into 5 treatments. Dry brewer's grain was substituted for maize offal in the experiment diets namely A to E at 0%, 15%, 30%, 45% and 60% respectively, as supplement to low quality, dry season cassava leaf top and Andropogan gayanus hay at 1:1 ratio that lasted for 56 days. After which 5 of the lambs (average bodyweight=$24.3{\pm}1.5kg$) were transferred to metabolism crates to determine the digestibility and nitrogen/protein balance studies. While the mean group intakes were (945.9, 996.1, 1,040.5, 1,148.5 and 1,037.7 g conc. DM/day), the growth rates were (115.1, 124.1, 152.5, 168.5 and 123.1 g liveweight gain/day), respectively. There was a recorded decline in both intake (p>0.05) and growth rate (p<0.05) as the level of dry brewer's grain was increased beyond 45% of the supplement. Similar trend was observed on the protein and organic matter efficiency ratios (p>0.05) together with the organic matter intake. The urine nitrogen output was also significant (p>0.05). The work further revealed that, at a certain critical level of intake, dry brewer's grain is able to support growth rates measurable to or better than those noted when feeding maize offal to lambs, and went on to prove dry brewer's grain as an attractive supplementary feed for the drier months of the year, in the Southeast of Nigeria.

• Fisheries and Aquatic Sciences
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• 제27권6호
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• pp.356-365
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• 2024

The study was conducted in the Terie River between January and April 2022. The objectives of the study were to assess the fish species composition, determine the length-weight relationship and condition factor and assess the water quality of the river using international water quality guideline for aquatic life. Gillnets with different mesh sizes, 4, 6, 8 and 10 cm were used to collect fish specimens in both dry and wet seasons. Immediately after capture, the total length (TL) and total weight (TW) of each individual were measured in centimeters and grams, respectively, and their relationship was determined using the power function. The physicochemical water quality parameters were analyzed using standard procedures and wagtech portable water quality Kits and Secchi Disk apparatus. A total of 667 fish specimens were collected from the Terie River, 410 and 257 in dry and wet seasons respectively. A total of six fish species, Oreochromis niloticus, Labeobarbus intermedius, Labeobarbus nedgia, Labeobarbus beso, Clarias gariepinus, and Ramius loti were recorded. For length-weight relationship and condition factor analysis, more abundant fish species (O. niloticus and L. intermedius) which were found in both seasons were selected. The length and weight relationship of L. intermedius were TW = 0.0073TL^3.04 in dry and TW = 0.0337TL^2.59 in we season indicated isometric and negative allometric growth respectively. While O. niloticus showed negative allometric growth, TW = 0.096TL^2.44 and TW = 0.0335 TL^2.76 in dry and wet seasons, respectively. The mean Fulton condition factor (FCF) of L. intermidus were 0.85 ± 0.03 and 0.94 ± 0.25 in dry and wet seasons, respectively. The FCF of O. niloticus was 1.70 ± 0.13 and 1.73 ± 0.12 in dry and wet seasons respectively. Except for ammonia, the physicochemical water quality parameters were with the permissible limit for aquatic life and are suitable for fishes Terie River. The river has commercially important fish specimens that could be used for food security and livelihood improvement. However, there is very limited fishing activity in the river due to less awareness on the value of fishes. Therefore, sustainable fishery development should be done in the river.