• 한국초지조사료학회지
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• 제13권2호
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• pp.112-121
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• 1993

To study management practices suitable for the least production loss of temperate pasture under summer stress, two different cutting dates (late June and mid July) under summer stress and five different nitrogen treatment application levels (0, 100. 200, 300 and 400 kg/ha) were tried during the trial period between Oct. of 1986 and Oct. of 1989. The late June cutting showed a statistically significant increase of dry matter yield of pasture in comparison with the mid-July cutting(P<0.05). Nitrogen application also gave significant increase in dry matter yield. Botanical composition at the 4th cuttings in 1988 and 1989 was dominated by weeds to the level of 50%, Application ofnitrogen at 200 kgs per ha was found to be the best with production of grasses at 70%, legumes at 10 % and weeds at 20% in botanical composition comparison of pastures at the 4th cutting time the last year, showing a great decrease of weeds. K contents of pasture in June cuttings showed to be more than them in July cutting, and N and Na contents increased with increases of the nitrogen application level. It was concluded that treatment with June cutting and nitrogen application of 200 kg per ha was a way to keep temperate pasture from summer stress in the Cheju area.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.333-333
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• 2017

This study was conducted to establish of cropping system for year-round forage crops production in east-southern part of Korea and investigated their productivity and feed values. Cropping systems were tested in experiment using oat (cv. Highspeed and Darkhorse) in spring and autumn season, corn (cv. Kwangpyeongok) and sorghum (ss-450) in summer season and rye (cv. Gogu) and triticale (cv. Joseong) in winter season. Considering the forage productivity and feed value such as acid detergent fiber (ADF), neutral detergent fiber (NDF) and total digestive nutrients (TDN), this result suggest that three cropping system for year-round forage crops production. The combinations with triticale (winter), corn or sorghum (summer) and oat (autumn) were would be suitable ones. And also the combinations with rye (winter), corn or sorghum (summer) and oat (autumn) were would be suitable. If forage crops cultivation was started in spring season, the combinations with oat (spring), oat (autumn), triticale or rye (winter), corn or sorghum (summer) and oat (autumn) were would be appropriable. For the more suitable cropping system, we are proceeding on verification experiment of year-round forage crops.

• 한국수산과학회지
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• 제24권1호
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• pp.39-51
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• 1991

굴 양식장 수역에 있어서 식물플랑크톤에 의한 기초생산력을 파악하기 위해 한산-거제만과 가막 양만을 대상으로 1년간 $^{14}C$ 법으로써 조사하였다. 한산-거제만의 경우, 일간기초생산력은 평균 $0.52gC/m^2/day(0.22{\~}1.02gC/m^2/day)$로 여름에 비교적 높고 겨울에 낮았다. 연간기초생산력은 $189gC/m^2/yr$로 추정되었다. 엽록소 a양은 평균 $1.70mg/m^3$로서 비교적 여름에 높았다. 가막양만의 경우, 일간기초생산력은 평균 $0.91gC/m^2/day\;(0.11{\~}3.61gC/m^2/day)$로 여름에 최고치 그리고 가을에 최저치를 보였다. 연간기초생산력은 $334gC/m^2/yr$로 추정되었다. 엽록소 a 양은 평균 $2.34mg/m^3$로서 여름에 최고치를 보였으며, 겨울에도 비 교적 높았다. 두 굴 양식장의 수면적을 고려하면, 식물플랑크톤에 의해 생산되는 탄소량은 한산-거제만이 9,450ton이고 가막양만이 37,000ton이었다. 본 조사수역의 기초생산력은 봄의 생산력 증가와 함께 여름에 높은 생산력을 보였다.

• Asian-Australasian Journal of Animal Sciences
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• 제16권7호
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• pp.988-995
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• 2003

Physiological parameters were measured on six primiparous, non-pregnant Holstein cows prior to peak lactation over a 3-month summer season in southwestern Taiwan. The objectives were to characterize heat stress-induced change in functionality of mammary gland under natural climates of tropical summer and to establish physiological indices applicable to this environment in referring to this change. Environmental and physiological readings, milk and blood samples were taken at 15:00 h biweekly for totally five time points during the study. Climate readings showed that the afternoon humidex value reached the highest (53.5) around mid summer. Rectal temperature of cows taken simultaneously varied between $38.26^{\circ}C$ and $40.02^{\circ}C$ in parallel to humidex. Milk production declined drastically from 29.2 to 22.2 kg/d the first month entering summer but leveled up at end of the summer season suggesting effects exerted by heat stress rather than stages of lactation. Lactose content decreased linearly (p<0.05) with times in summer, from 4.69 to 4.38%. On the other hand, activity of N-acetylglucosaminidase (NAGase) in milk increased linearly to over two folds (p<0.05) during the same intervals. Elevations of fractional constituent of BSA in whey protein and serum cortisol level were also noticed in the course. Measurement of arteriovenous concentration (A-V) difference across the mammary gland demonstrated net uptake of glucose and net release of urea throughout the study period. The amount of urea released from mammary gland increased (p<0.05) progressively from 1.54 to 7.76 mg/dl during summer. It is concluded that gradual regression of mammary gland occurred along the humid tropical summer season. This regression is likely initiated through elevation of body temperature, which is irreversible above certain point. The increased release of urea from mammary gland during heat stress suggests its potential role as an early indicator of suboptimal mammary function.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.48-48
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• 2017

The objectives of this study were to determine the dominance frequency of plant species between spring and summer, to provide useful information toward the conservation to increasing production cattle feed in grazing area in Hiroshima, Japan. The frequency of dominant plant species can adapt in the spring and summer, that consist of Paspalum dilatatum (spring 69.32% and summer 78.98%), Paspalum notatum (spring 47.73% and summer 98.30%), Trifolium repens (spring 73.86% and summer 81.25%). The observed plant species also influenced some productivity, which consists of plant height (spring 16.64 cm and summer 21.55 cm), vegetation cover rates (spring 77.18% and summer 81.36%, chlorophyll content (spring 41.72 mg/g Fw and summer 36.28 mg/g Fw), diversity index (spring 0.94 and summer 0.80), evenness index (spring 0.93 and summer 0.67), and species numbers (spring 32.0 and summer 21.0). It is proposed that Paspalum dilatatum, Paspalum notatum, and Trifolium repens, can be used to increase productivity of plant species as cattle feeds.

• 한국환경과학회지
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• 제19권3호
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• pp.269-279
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• 2010

The relative contributions of physical and chemical processes to the production of ozone ($O_3$) were evaluated based on an integrated process rate (IPR) analysis using the MM5/CMAQ in a downtown (i.e., Yangsan_U) and suburban area (i.e., Ungsang) on high ozone days during spring and summer in 2006 (28 April and 8 August 2006). The IPR includes a horizontal advection (HADV) and diffusion (HDIF), a vertical advection (ZADV) and diffusion (VDlF), a dry deposition (DDEP), and a chemistry (CHEM). The VDIF in Yangsan_U was found to be the most dominant contributor (29.5% in spring and 32.1% in summer) to high $O_3$ concentrations, followed by the HADV and ZADV. In contrast, the contributions of the HADV (40.3% in spring and 32.3% in summer) in Ungsang were significantly higher than those of VDIF and ZADV. Moreover, $O_3$ production due to the chemical effect in the two areas (especially in Ungsang) during summer was found to be moderately higher than that during spring.

• 환경생물
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• 제24권2호
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• pp.186-194
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• 2006

Nitrogen dynamics of Seagrass Zostera marina were investigated in both Dongdae Bay and Ojiri from March to August, 2004. All seagrass samples were separated into four fractions such as leaves (new and adult), sheath and rhizome in order to understand temporal variations of nitrogen content in different fractions of Zostera marina. There are temporal variations of shoot production rates and total nitrogen contents in their different fractions at both study areas. Leaf production were almost 4 to 5 fold higher in summer than in winter. The irradiance is the primary factor controlling the leaf production of Zostera marina in both sites although water temperature also influence its productivity. Nitrogen contents of leaves were overall low in summer than in winter, but nitrogen content of rhizome increased during the summer season. In addition, nitrogen contents of new leaves were mostly higher than adult leaves in spite of lower nitrogen content of new and adult leaves in high productivity period. This result suggests that Zostera marina seems to have significant translocation ability of nitrogen in a shoot. The nitrogen content of leaf tissue may reflect nutritional nitrogen availability.

• Asian-Australasian Journal of Animal Sciences
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• 제14권1호
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• pp.41-47
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• 2001

Ruminal degradation characteristics of dry matter (DM), neutral detergent fiber (NDF) and crude protein (CP) in fresh leaves of two Japanese native grasses (Zoysia japonica and Miscanthus sinensis) and one sown temperate grass (Dactylis glomerata) were investigated by an in sacco method in spring (mid-May), summer (mid-July) and autumn (mid-September). Japanese native grasses had higher NDF and lower CP concentrations than D. glomerata, and the CP concentration in native grasses decreased in autumn. Ruminal degradability of DM, NDF and CP was lower in native grasses than in D. glomerata (p<0.05) in all seasons. DM and NDF degradability decreased in summer for Z. japonica and D. glomerata, while it decreased in autumn for M. sinensis. CP degradability in Z. japonica was constant throughout the seasons, whereas that in M. sinensis greatly decreased in summer and autumn (p<0.05). It was concluded that Z. japonica could stably supply ruminally digestible nutrients for grazing animals in Japanese native pasture. However, the degradation characteristics of freshly chopped native grasses did not fit the exponential model of $D=a+b(1-e^{-ct})$ proposed by Ørskov and McDonald.

• 한국패류학회지
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• 제20권1호
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• pp.45-53
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• 2004

This study have conducted to calibrate the productivities on the mussel (Mytilus galloprovincialis) cultures in Jinhae Bay. Annual water temperature, salinity and dissolved oxygen have varied to 7.2-$25.9^{\circ}C$, 32.9-34.0 psu, 7.9-8.7 mg/l, respectively. In April, the smallest size of spat, 3.3 mm in shell length, have recruited, and 82.5 mm have recorded to the maximum. In summer, variations of growing up between individuals showed both shell length and weights at same cohort. Annual production at 2 m, 5 m, 8 m depth calculated to 10.91, 10.85 and 9.19 gWWt/ind./yr, respectively. Mussel cultivated in the upper part of the water column (two meter depth) were significantly longer and heavier than those in lower part (eight meter depth). After the recruitment, monthly production showed gradual increment at all positions during summer. As results, annual production of mussel cultivated seemed to be controlled by conditions of growing up in summer. Based on the productivities calculated to this study, the total annual production of the mussel cultivated in Jinhae Bay have estimated about 196 ton/ha/yr.

• Ocean and Polar Research
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• 제32권3호
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• pp.177-186
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• 2010

A sequential extraction technique was used to study sediment phosphorus speciation and its relative importance in the intertidal flat of Keunso Bay during summer and winter for a better understanding of the phosphorus cycle and bioavailability in intertidal sediments. Loosely sorbed P contents were the lowest among the five P-pools and showed little seasonal or spatial variation. Although Fe-bound P contents were almost constant in winter, they decreased rapidly with sediment depth in summer. The dissolution of Fe oxides, used as an oxidant for the anaerobic respiration, ascribed the rapid decrease of Fe-bound P in summer. Al-bound P contents displayed little seasonal variation, but showed a large spatial variation, with higher values in the upper intertidal flat. Comprising about 50% of total P, Ca-bound P contents were the highest among the five P-pools. Ca-bound P contents were higher in winter than summer, but did not exhibit a clear spatial variation. Organic P contents were higher in summer than winter, which was associated with higher primary production and clam biomass in summer. Organic P contents were higher in the lower intertidal flat than the upper intertidal flat. In Keunso Bay, bioavailable P contents of the intertidal flat comprising about one third of total P ranged from 2.41 to 5.09 ${\mu}molg^{-1}$ in summer and 3.82 to 5.29 ${\mu}molg^{-1}$ in winter. The bioavailability of P contents was higher in the lower intertidal flat than the upper intertidal flat, which was attributed to the large clam production in the lower intertidal flat.