• 한국토양비료학회지
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• 제31권4호
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• pp.384-391
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• 1998

목재에너지 공급을 위해 1987년 미국 뉴욕주립대 연습림에 조성된 버드나무(Salix spp.) 조림지를 대상으로, 매년 벌채되는 지상부 biomass와 양분의 양을 측정하여 벌채에 의한 양분수탈을 평가하였다. 5개의 버드나무 clone과 1개의 잡종 포플러가 식재되었으며, 식재지의 시비구에 매년 N($336kg\;ha^{-1}$), P($112kg\;ha^{-1}$), K($224kg\;ha^{-1}$)를 시비하였으며, 조림지에 식재된 모든 공시목은 매년 벌채되었다. 식재 후 7년동안(1987-1993) 식재지로부터 벌채에 의한 연평균 N, P, K, Ca, 그리고 Mg의 수탈은 각각 30-70, 4-10, 14-40, 19-59 그리고 $3-5kg\;ha^{-1}$이었다. 시비구에서 높은 biomass 생산과 양분수준 때문에 대조구보다는 시비지역의 수목에서 양분수탈이 높게 나타났다. 비록, 벌채로 인한 양분수탈이 대조구보다 시비지에서 큰 것으로 나타났지만, 그 양은 시비처리의 양보다 적기 때문에 토양의 양분 수준에 크게 영향을 주지는 않을것으로 사료 된다. 시비없이 벌채에 의한 양분수탈은 장기간에 걸쳐 토양양분의 결핍을 가져올 것으로 판단된다. 전체 식재 clone중 clone SV1의 양분 유효도가 가장 높았다.

• 한국환경과학회지
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• 제30권8호
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• pp.659-671
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• 2021

The physicochemical properties of soil and the yield and quality of rice (Oryza sativa L. cv. Sailmi) were assessed using Italian ryegrass (Lolium multiflorum Lam. cv. Kowinearly)-rice double cropping systems in the paddy fields at Goseong and Miryang in southern Korea. The average temperatures during the ripening period were approximately 1 ℃ higher than the optimal temperature for rice ripening and the sunshine duration was reduced by frequent rainfall. Consequently, it was slightly below the optimal conditions required for rice ripening. In the soil at Goseong, winter Italian ryegrass cropping increased the pH, electrical conductivity, and the contents of organic matter, total nitrogen (T-N), available P₂O₅, K, Ca, and Mg than winter fallowing. Particularly, the contents of T-N and available P₂O₅increased significantly. In the soil at Miryang, Italian ryegrass slightly increased the electrical conductivity and the T-N, Mg, and Na contents. Therefore, winter Italian ryegrass cropping improved the physicochemical properties of paddy soils; however, Italian ryegrass-rice double cropping slightly reduced the culm length at both Goseong and Miryang, without markedly changing the panicle length or number compared to fallow-rice cropping. Furthermore, at Goseong, Italian ryegrass-rice double cropping slightly decreased the spikelet number and milled rice yield, and increased the ripened grain rate; however, at Miryang, contrasting results were observed. In addition, fallow-rice cropping revealed no differences in the head rice or opaque rice rates. The protein content was slightly increased in Italian ryegrass-rice double cropping, without significant changes in the amylose content or Toyo value, compared to that in fallow-rice cropping. The peak and breakdown viscosities were slightly decreased. These results indicate that winter Italian ryegrass cropping might alter rice taste but may not exhibit remarkable negative effects on rice cultivation. Therefore, Italian ryegrass-rice double cropping system is recommended for paddy fields in southern Korea. Nevertheless, to increase the rice yield and quality, fertilization standards for rice cropping that consider the changes in the T-N and organic matter contents in paddy fields caused by winter Italian ryegrass cropping need to be established.

• 한국어류학회지
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• 제29권3호
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• pp.190-196
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• 2017

피라미의 수정란을 부화 사육하여 난 발생 및 자치어 형태발달을 관찰하였다. 실험어는 2016년 6월 낙동강 수계인 위천에서 어미를 포획하여 인공수정 하였다. 난의 크기는 1.68~1.78 mm (평균${\pm}$SD, $1.73{\pm}0.07mm$, n=30)였고, 부화 시간은 70시간이 소요되었다. 부화 직후 자어는 전장 5.39~5.42 mm ($5.40{\pm}0.02mm$, n=10)였고, 부화 후 8일째 후기 자어는 전장 7.89~7.93 mm ($7.91{\pm}0.02mm$, n=10)로 꼬리지느러미에 10개의 줄기가 형성되었으며, 부화 후 44일째 치어는 전장 16.1~16.5 mm ($16.3{\pm}0.28mm$, n=10)로 각 부위별 지느러미 줄기수가 정수에 달하였다.

• 한국초지조사료학회지
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• 제17권2호
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• pp.110-116
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• 1997

The objective of this experiment was to suggest the optimum nitrogen fertilization level for orchardgrass(0G)- red clover(RC) mixtures. The field trials were conducted from 1993 to 1994 in order to evaluate the dry matter yield, botanical composition, chemical composition, dry matter digestibility(DMD), crude protein dry matter (CPDM) and digestible dry matter(DDM) yields on the nitrogen levels( 0, 50, 100, 150 and 300kgha). The results obtained were summarized as follows : 1. With increasing nitrogen levels, the DM yield of OG-RC mixttures significantly increased(P<0.05). The maximum total DM yield (7,964kgha) was obtained at N 300kgha level, However, there was no significant difference between N 150 and 300kgha. 2. With increasing the nitrogen levels, the botanical composition of OG in OG-RC mixttures was significantly increased(P< 0.05), whereas that of RC was remarkably decreased(P< 0.05). 3. The CP content was decreased by increasing nitrogen level(P

• 한국농공학회지
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• 제31권3호
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• pp.93-102
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• 1989

With an objective to provide basic information for the management and the prediction of eutrophication in lentic water Systems, total amount of Kjeldahl nitrogen(T-N) and phosphorous(T-P) from irrigated water and drained water from flooded paddies were investigated during the rice growing period of 1988. A 29.3 ha paddies near Jungnam-myun, HwaSung-gun, Gyungi Province, Korea was instrumented for measuring runoff and sampling irrigated water and drained water from paddies. The following conclusions may be drawn from the result of this study. 1.During 115 days of investigation, T-N load for paddies was 362.6kg and T-P 63.44kg.These would be converted to 12.4kg T-N/ha and 2.17kg T-P/ha, respectively. 2.The T-N and T-P loadings in different periods showed a significant difference. The 25% of T-N loading was drained soon after fertilization period and 60% was drained during the rainy season from July 5 to July 24. 3.Annual loadings from paddies could be calculated to 30kg T-N/ha/year and 52kg T-P/ha/year considering non-measurement periods. 4.After the rainy season, the nutrient loads from drained water showed much less than those from irrigated water, and it may be suggested that the paddies would act as a stabilization pond. 5.The average concentrations of nutrients at 0.9km downstream from investigated paddies were 2.02(T-N) mg/l and 0.52(T-P) mg/I, which were 1.82(T-N) mg/l and 0.056(T-P)mg/l lower than those of drained water from paddies.

• 한국발생생물학회지:발생과생식
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• 제22권1호
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• pp.39-53
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• 2018

The purpose of this study is to investigate the early life history of the Rhodeus fish, Rhodeus uyekii and R. ocellatus, in the Nakdong River to use as the preliminary data for the systematic study. The embryos used in the study were fertilized eggs (embryo) and larvae after artificial fertilization. The long diameter of the eggs of the R. uyekii was 3.39-3.97 mm (average $3.68{\pm}0.41mm$, n=30) and the short diameter was 1.36-1.55 mm (average $1.45{\pm}0.13mm$, n=30). The long diameter of the eggs of the R. ocellatus was 2.53-2.71 mm (average $2.62{\pm}0.12mm$, n=30) and the short diameter was 1.47-1.60 mm (average $1.53{\pm}0.09mm$, n=30). Hatching time was 48 hours for the R. uyekii and 50 hours for the R. ocellatus given that the average water temperature was $21.5^{\circ}C$. The hatched larvae were 4.95-5.00 mm (average $4.98{\pm}0.04mm$, n=5) for the R. uyekii and the total length was 3.66-3.69 mm (average $3.67{\pm}0.02mm$, n=5) for the R. ocellatus. R. uyekii was found to be 15.5-15.8 mm at total length (average $15.6{\pm}0.21mm$, n=5) on the 56 days after hatching with the number of dorsal fins being ⅲ-9, anal fins ⅲ-10, ventral fins ⅲ-5. The R. ocellatus was found to be 15.8-16.0 mm (average $15.9{\pm}0.14mm$, n=5) at total length on the 58 days with the number of dorsal fins being ⅲ-11, anal fins ⅲ-12 and ventral fins ⅲ-5 where the number of all fin stalks reached maximum.

• 한국초지조사료학회지
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• 제10권2호
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• pp.89-95
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• 1990

This experiment was carried out to determine the effects of nitrogen(N) fertilizer levels (0, 120, 240 and 360kg $ha^{-1}Y^{-1}$ Y-') on seasonal grass growth, dry matter (DM) yield and botanical composition in pasture under shade condition. Investigation date was on 7 , 14, 21, 28 and 35 days after harvesting in spring (May), summer (July) and autumn (Sept.), 1988, respectively. Shade degree was controlled artificially ca. 45-50%, and each annual level of N was distributed 5 times equally. Grass growth and DM productivity were most vigorous in spring. Higher DM yield was produced with N 240 kg spring, and Nl2Okg in summer and autumn. Higher significant relationships, in spring, were found between grass height and DM, and N level and DM yield. However, low relationships were observed between those in summer and autumn. In botanical composition, grass coverage was decreased in summer and autumn, and bareland was increased, especially in higher N plots. Based on the results, it is suggested that 200kg $ha^{-1}$ of N in this experiment is more effective for forage production and pasture persistence. Also a littie more amount of N (50-70kg $time^{-1}$) in spring, and low level of N (20-30kg $time^{-1}$) in summer and autumn may be desirable.

• 한국토양비료학회지
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• 제48권6호
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• pp.610-617
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• 2015

The impact of 1 pound of nitrous oxide ($N_2O$) on warming the atmosphere is almost 310 times that of 1 pound of carbon dioxide. Agricultural soil management is the largest source of $N_2O$ emissions, accounting for about 73% of total $N_2O$ emissions. This study was conducted to evaluate the nitrous oxide emission in the cultivation of soybean during the first year of No-tillage (NT) and Conventional-tillage (CT) practices, under the various conditions such as different kinds of fertilizers, soil temperature, and moisture level. In the experiment, we set CT and NT treatments into 4 different groups - control treatments (no fertilization), green manure treatments, chemical fertilizer treatments and organic manure treatments. In the case of chemical fertilizer treatments, $N_2O$ emission of NT treatment was 7.78 to 22.59% lower than CT treatment. In organic manure treatment, $N_2O$ emission of NT treatment was 6.62% higher than CT treatment in August. But In July and September, $N_2O$ emission of NT treatment was 9.50% 28.38% lower than CT treatment, respectively. Soil temperature was correlated with $N_2O$ emission positively. In the future, continued long-term research on influence of various environmental factors on the generation of $N_2O$ and the economic value of no-till farming is required.

• 한국토양비료학회지
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• 제50권6호
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• pp.530-537
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• 2017

Composted animal manure added for improving soil quality and enhancing crop productivity can lead to greenhouse gas emissions such as nitrous oxide ($N_2O$) by processes of nitrification and denitrification. In addition, the amount of $N_2O$ emission from composted manure amended soils can vary greatly with composted manure type or different soil type. Therefore, the influence of cattle composted manure on $N_2O$ emissions was evaluated during growth of sweet potato (Ipomoea batatas). The treatments included control, conventional fertilization (CF), and CF + cattle composted manure (CCM) $10Mg\;ha^{-1}$ were applied in the spring. $N_2O$ emissions were significantly affected by composted manure and chemical fertilizer and the CCM had greater N2O emissions compared with other treatments. The majority of $N_2O$ emissions occurred shortly after composted manure and chemical fertilizer application compared with the rest of the growing seasons for all treatments. Also, $N_2O$ flux was associated with water-filled pore space (WFPS) at all treatments. On average of $N_2O$ emission accumulation, the CCM was 1.5 times greater than control treatment while there was no difference between CF and control.

• 한국발생생물학회지:발생과생식
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• 제20권3호
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• pp.247-254
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• 2016

Cytological changes of the epithelial cells according to the developmenatal phases of the seminal vesicle related to the spermatogenic stages in the testicular lobules during spermagenesis in male Neptunea (Barbitonia) cumingii (Gastropoda: Buccinidae) were investigated monthly by electron microscopical and histological observations. N. (B) cumingii is dioecious, and an internal fertilization species. The male genital organ is located near the tentacles. The spermatozoon is approximatley $50{\mu}m$ in length. The axoneme of the tail flagellum consists of nine pairs of microtubles at the periphery and one pair at the center. The process of germ cell development during spermatogenesis can be divided into five succesive stages: (1) spermatogonia, (2) primary spermatocytes, (3) secondary spermatocytes, (4) spermatids, and (5) spermatozoa. A considerable amount of spermatozoa make their appearance in the testicular lobules (or acini) and some of them are tranported from the testis towards the seminal vesicles until late July. In this study, the developmental phases of the epithelial cells of the seminal vesicles of N. (B.) cumingii could be classified into four phases: (1) S-I phase (resting), (2) S-IIphase (early accumulating), (3) S-III phase (accumulating), and (4) S-IV phase (spent). However, in case of N. (B.) arthritica cumingii, the developmental phases of the seminal vesicle were devided into three phases: (1) resting, (2) accumulating and (3) spent. Granular bodies in the inner layer of the seminal vesicles are involved in resorption of digestion of residual spermatozoa.