• Development and Reproduction
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• v.12 no.3
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• pp.283-288
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• 2008

The Pseudogobio esocinus were caught at Wyuleo-ri, Gyeombaek-myeon, Boseong-gun, Jeollanamdo from April to May 2003. The fishes were incubated in transparent aquarium located at the laboratory of Chonnam National University, and their embryonic and larval development were observed. The fertilized eggs were spherical, semitransparent, and adhesive, and were $1.98{\pm}0.19mm$ (n=50) in diameter. The embryo, including 31$\sim$32 myotomes, hatched through egg membrane at 164 hrs after fertilization. The newly-hatched larvae were $4.61{\pm}0.83mm$ (n=10) in total length (TL). At that moment, yolk was not absorbed, and mouth and anus were not open. Star and spot shaped melanophores were distributed on the lens, and dorsal, ventral, and caudal parts. At 42 days after hatching, larva was $16.22{\pm}0.65mm$ (n=10) in TL. Melanophores were scaterred at head, back, and side parts. Morphological features of the embryo were transferred to juvenile stage showing similar features with those of the adult fish.

• Korean Journal of Environmental Agriculture
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• v.14 no.1
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• pp.97-108
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• 1995

Nitrate concentration and ${\delta}^{15}N$ value in the groundwater in Miyakojima Island, Okinawa, were measured during 1992-1993. Water from the shallow and the deep wells at the ten separate sites were sampled. Mineral contents and natural nitrogen isotope abundance(${\delta}^{15}N$) were analyzed using a liquid chromatography and a mass spectrometry (Finnigan MAT 252). Except for waters which were directly influenced by sea water invasion, most of the groundwater showed small variations among their mineral contents and ${\delta}^{15}N$ values. The average nitrate nitrogen concentrations were $1.4{\sim}11.5mgL^{-1}$ and average ${\delta}^{15}N$ values were +4.3${\sim}$+9.7$%_o$. From the nitrate concentration and ${\delta}^{15}N$ value observed, the types of the groundwater could be categorized into four groups, such as high ${\delta}^{15}N$ and high nitrate, high ${\delta}^{15}N$ and medium nitrate, low ${\delta}^{15}N$ and medium nitrate, and low ${\delta}^{15}N$ and low nitrate, reflecting the main source of nitrate contamination, such as animal and domestic waste, animal waste and soil organic matter, soil organic matter and chemical fertilizer, and chemical fertilizer, respectively. It was discussed that the lowest ${\delta}^{15}N$ value was higher than the ${\delta}^{15}N$ value of the chemical fertilizers used in this island(-3.9${\sim}$-1.4$%_o$), then considerable amounts of nitrogen must be lost by ammonium evaporation or denitrification after fertilization.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1239-1244
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• 2011

Importance of climate change and its impact on agriculture and environment has increased with a rise of greenhouse gases (GHGs) concentration in Earth's atmosphere. Nitrous oxide ($N_2O$) emission in upland fields were assessed in terms of emissions and their control at the experimental plots of National Academy of Agricultural Science (NAAS), Rural Development Administration (RDA) located in Suwon city. It was evaluated $N_2O$ emissions with different growing periods (spring and autumn seasons), tillage and no tillage conditions in a chinese cabbage field. The results were as follows: 1) An amount of $N_2O$ emissions were high in the order of Swine manure compost>NPK>Hairy vetch+N fertilizer. By tillage and no tillage conditions, $N_2O$ emissions were reduced to 33.7~51.8% (spring season) and 31.4~76.7% (autumn season) in no-tillage than tillage conditions. 2) In autumn season than those spring season, $N_2O$ emissions at NPK, hairy vetch+N fertilizer and swine manure compost were reduced to 49.6%, 39.0% and 60.0%, respectively, in tillage treatment and 59.5%, 70.6% and 58.7%, respectively, in no-tillage treatment. 3) $N_2O$ emission measured in this study was 15.2~86.4% lower with tillage and no tillage treatments than that of the IPCC default value (0.0125 kg $N_2O$-N/kg N).

• Korean Journal of Environmental Biology
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• v.22 no.2
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• pp.300-307
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• 2004

The chloroacetanilide herbicide alachlor (2-chloro-2', 6'-diethyl-N-(methoxymethyl)-acetanilide) and organochlorine insecticide endosulfan (6, 7, 8, 9, 10, 10-hexachloro-l, 5, 5a, 6, 9, 9a-hexahydro-6, 9-methano-2, 3, 4-benzodioxathiepin-3-oxide)are the highly toxic agricultural chemicals. Bombina orientalis is one of the most common amphibians in the world and comprises a large proportion of their total number. B. orientalis spawns in the farming regions at Spring when the massive application of agricultural chemicals occurs. These chemicals in farmland may threaten the reproduction of this frog. Therefore, we examined the embryotoxic and survival effects of alachlor and endosulfan at various concentrations in B. orientalis embryos. The survival rates of embryos at 312h post fertilization treated with alachlor and endosulfan were decreased with concentration dependent manner. Also, developmental malformations appeared by alachlor and endosulfan in B. orientalis embryos. The malformations showed in order of frequency with bent trunk, tail dysplasia, bent tail, thick-set body and ventral blister in alachlor treated embryos. The exposure of endosulfan produced 7 types of severe external malformations with tail dysplasia, pectoral blister, bent trunk, bent tail, cephalic dysplasia, ventral blister, and thick-set body. Following exposure to alachlor and endosulfan the types of malformations were diverse, suggesting these chemicals target multiple events in embryonic and larval development in this species. These results suggested that alachlor and endosulfan were detrimental for survival and development of B. orientalis embryos.

• Journal of The Korean Society of Grassland and Forage Science
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• v.11 no.2
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• pp.108-115
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• 1991

A field experiment was conducted to evaluate the effects of cattle compost application on the change of soil physical properties and their relationship to yield performance of selected main forage crops. Maize(CV. Suweon 19) and sorghum hybrids(CV. Pioneer 9'31) as a summer crops and winter rye were grown on newly reclaimed red yellow soils(Fine loamy, Typic Hapludults) under different application rate of cattle compost associated with chemical NPK fertilization, from Oct. 1986 to Sept. 1989. Experimental field was laid down as a split plots design with four replications. The results obtained are summarized as follows: 1. Cattle compost application reclaimed soil physical propeties, such as formation of granular structure and water holding capacity, and it result in a great increase of plant growth and the rate of dry matter accumulation. 2. While cattle compost treatment reduced the portion of soild phase of the three phase constituents of soils, it increased the portion of air phase and liquid phase comparatively. 3. Organic matter, N, P, K, and mineral content in soil were markedly increased in the plot treated with compost. 4. Cattle compost application increased fodder production both in maize-rye and sorghum hybrids-rye cultivation. Annual dry matter yield of maize-rye cropping was 2183(NI'K only), 2425(NPK+compvst 3000 kg) and 2800kg/lOa(NPK + compost 6000kg/10a).

• Journal of Animal Environmental Science
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• v.3 no.1
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• pp.35-42
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• 1997

The purpose of this study is to investigate the effect of the biologically treated animal wastewater as a liquid fertilizer in the paddy rice. The treated water has content of the ammonia nitrogen 24mg/I and nitrate 40 mg/I on an average in the first year. A trace of nitrite has been shown. The phosphate content was 92 mg/I on an average. The amount of yielded rice was 365kg/10a for test 1 (no fertilizer), 388dg/10a for test 2(chemical fertilizer), 526kg/10a for test 3 (treated water) respectively. The treated water showed 35% more in production than the chemical fertilizer. The treated water has content of the ammonia nitrogen 40mg/I and nitrate 67mg/I on an average in the second year. A trace of nitrite has been shown. The phosphate content was 57mg/I on an average. The amount of yielded rice was 402kg/10a for test 1, 505kg/10a for test 2, 607kg/10a for test 3 respectively. Yield of unhulled rice was 20% more in the plot of treated water than that of chemical fertilizer.

• Journal of Ecology and Environment
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• v.35 no.4
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• pp.307-311
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• 2012

This study was conducted to evaluate the dynamics of soil respiration (total soil and heterotrophic respiration) following fertilizer application in red pine forests. Fertilizer (N:P:K = 113:150:37 kg/ha), which reflects current practices in Korean forest, was applied in April 2011, and total soil and heterotrophic respiration rates were monitored from April 2011 to March 2012. Monthly variation of total soil and heterotrophic respiration rates were similar between the fertilizer and control treatments, as soil temperature was the dominant factor controlling the both rates. Total soil respiration rates during the study period were not significantly different between the fertilizer (0.504 g $CO_2\;m^{-2}\;h^{-1}$) and control (0.501 g $CO_2\;m^{-2}\;h^{-1}$) treatments. However, the proportion of heterotrophic respiration was higher in the fertilizer (78% of total soil respiration rates) than in the control (62% of total soil respiration rates) treatments. These results suggest that current fertilizer practices in Korea forest soil do not substantially affect total soil respiration rates.

• Journal of Environmental Science International
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• v.29 no.4
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• pp.423-434
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• 2020

The effects of amino acid and/or urea liquid fertilizer application on the growth and phytochemicals of Perilla leaves were summarized as follows; The fresh weight of the perilla leaves was in the order of CF, CL, KLF, and control, and 39.7 g, 37.4 g, 36.5 g and 32.3 g were measured. The plant height increased by 71.6 cm in the CF treatment than in the control(54.6 cm). The number of nodes was 14.3 node in CF treatment and 19% more than control(12 node). The vitamin C content tends to be increased by fertilizing the amino acid solution in the perilla leaf. The components of polyvalent unsaturation of n-6 origin were measured in CF treatment, KLF treatment, and control in 10.19 mg, 10.18 mg, and 9.38 mg per 100 g, respectively. Glutamic acid, aspartic acid, leucine, arginine, alanine and lysin were contained in perilla leaf amino acid. Glutaminic acid content was found to be 455.1 mg, 495.6 mg, and 478.8 mg in the control, KLF and CF treatment per 100 g, respectively. Effective nutrition management using amino acid fertilizer optimizes crop yield and profitability, it is important to reduce the negative environmental risks of using fertilizer.

• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.5
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• pp.151-159
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• 2003

Absorbent Biofilter Systems (ABS), composed of an anaerobic septic tank, a pump chamber and an absorbent biofilter tank, have been found to economically provide rural on-site wastewater treatment. This study was conducted to assess the potential of ABS effluent as an alternative water resource for agricultural and environmental use, with respect to the removal of pathogenic microorganism and their fertilization effect. A pilot scale ABS was used to compare its removal efficiency of pathogens from effluent water. Overall, more than 95 percent of Salmonella and E. coli were removed. This result demonstrates that a significant reduction in the pathogenic microorganism of effluents can occur in ABS, which implies the feasibility for the use of ABS effluent in agriculture and environment, with the provision of a further simple disinfection step, in order to satisfy the WHO guidelines for the microbiological quality in agriculture. In addition, because of the abundant nutritional content of ABS effluent, the substitution effect of fertilizer (N, P and K) in paddy irrigation, i.e. 2/3 for nitrogen, l/3 for phosphorus and 1/5 for potassium would be expected. Based on the experimental data, the ABS effluent could be used as a new alternative water resource for paddy irrigation, as well as for environmental purposes, such as supplying water to ecological parks in rural villages.

• Asian-Australasian Journal of Animal Sciences
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• v.11 no.3
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• pp.307-310
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• 1998

The present studies were undertaken to evaluate the effects of a low concentration of dimethyl-sulfoxide (DMSO) on in vitro maturation and development of bovine oocytes fertilized in vitro. Significantly more oocytes reached the metaphase stage of the second meiotic division in TCM-199 supplemented with $50{\mu}M$ DMSO than in the control medium (p < 0.05), and the highest rates of development up to the blastocyst stage were obtained when $50{\mu}M$ DMSO was added to the maturation and culture media (p < 0.05). The avarage of cell numbers of the blastocysts, expanded and hatched blastocysts cultured with $50{\mu}M$ DMSO were 81.7, 125.7 and 129.9 cells, respectively. The proportion of blastocysts with normal chromosome numbers was 90.5%. These results suggest that the addition of $50{\mu}M$ DMSO is beneficial for the maturation of bovine oocytes and production of the blastocysts with high quality.