• Korean Journal of Agricultural and Forest Meteorology
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• v.6 no.3
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• pp.149-163
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• 2004

Evapotranspiration (ET) is a critical component of the hydrologic cycle which influences economic activities as well as the natural ecosystem. While there have been numerous studies on ET estimation for homogeneous areas using point measurements of meteorological variables, monitoring of spatial ET has not been possible at landscape - or watershed - scales. We propose a site-specific application of the land surface model, which is enabled by spatially interpolated input data at the desired resolution. Gyunggi Province of South Korea was divided into a regular grid of 10 million cells with 30m spacing and hourly temperature, humidity, wind, precipitation and solar irradiance were estimated for each grid cell by spatial interpolation of synoptic weather data. Topoclimatology models were used to accommodate effects of topography in a spatial interpolation procedure, including cold air drainage on nocturnal temperature and solar irradiance on daytime temperature. Satellite remote sensing data were used to classify the vegetation type of each grid cell, and corresponding spatial attributes including soil texture, canopy structure, and phenological features were identified. All data were fed into a standalone version of SiB2(Simple Biosphere Model 2) to simulate latent heat flux at each grid cell. A computer program was written for data management in the cell - based SiB2 operation such as extracting input data for SiB2 from grid matrices and recombining the output data back to the grid format. ET estimates at selected grid cells were validated against the actual measurement of latent heat fluxes by eddy covariance measurement. We applied this system to obtain the spatial ET of the study area on a continuous basis for the 2001-2003 period. The results showed a strong feasibility of using spatial - data driven land surface models for operational monitoring of regional ET.

• The Korean Journal of Pesticide Science
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• v.7 no.2
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• pp.123-130
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• 2003

The Environmental Impact Quotient(EIQ) has been used to organize the extensive toxicological and soil residue data available on some fruit vegetables pesticides into a usable form for field use. It addresses a majority of the environmental concerns that are encountered in agricultural systems including farm worker, consumer, ecological and environmental safety. The EIQ made use of the rating system by using the EIQ equation. The EIQ of pesticides registered for oriental melon was higher than that of other in terms of farm worker, consumer and environmental safety. Pesticides registered for red pepper showed highest EIQ in ecosystem. The EIQ decreased in order of insecticide> fungicide> herbicide> plant growth regulator. The environment Impact Quotient for the pesticides registered in fruit and vegetables decrease gradually.

• Microbiology and Biotechnology Letters
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• v.21 no.1
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• pp.66-73
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• 1993

Psychrotrophic bacterial strains utilizing crude oil as their sole carbon and energy sources were isolated from Antarctic soil and sea sediments. One of the strains named AI-I showed the hightest activity for emulsification of crude oil and the best growth. This strain was identified as Acinetobacter calcoaceticus. A. calcoaceticus AI-I strain contains a plasmid (OCT plasmid) which was related to the utilization of alkane compounds. The molecular weight of this plasmid was estimated to be about 110 Md by agarose gel electrophoresis. The cured strain of A. calcoaceticus AI-I strain (OCT ) was not able to utilize normal hydrocarbon compounds ($C_6C_{17}$) as carbon and energy sources. A. ca/coaceticus AI-1 was resistant to ampicillin and sensitive to streptomycin, kanamycin, chloramphenicol, tetracycline. The results suggested that this strain carries a plasmid (OCT) responsible for oil utilization which is quite stable and might be concerned with antibiotics resistancy.

• Journal of Ecology and Environment
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• v.41 no.2
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• pp.34-44
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• 2017

Background: Monitoring terrestrial vegetation cover condition is important to evaluate its current condition and to identify potential vulnerabilities. Due to simplicity and low cost, point intercept method has been widely used in evaluating grassland surface and quantifying cover conditions. Field-based digital photography method is gaining popularity for the purpose of cover estimate, as it can reduce field time and enable additional analysis in the future. However, the caveats and uncertainty among field-based vegetation cover estimation methods is not well known, especially across a wide range of cover conditions. We compared cover estimates from point intercept and digital photography methods with varying sampling intensities (25, 49, and 100 points within an image), across 61 transects in typical steppe, forest steppe, and desert steppe in central Mongolia. We classified three photosynthetic groups of cover important to grassland ecosystem functioning: photosynthetic vegetation, non-photosynthetic vegetation, and bare soil. We also acquired normalized difference vegetation index from satellite image comparison with the field-based cover. Results: Photosynthetic vegetation estimates by point intercept method were correlated with normalized difference vegetation index, with improvement when non-photosynthetic vegetation was combined. For digital photography method, photosynthetic and non-photosynthetic vegetation estimates showed no correlation with normalized difference vegetation index, but combining of both showed moderate and significant correlation, which slightly increased with greater sampling intensity. Conclusions: Results imply that varying greenness is playing an important role in classification accuracy confusion. We suggest adopting measures to reduce observer bias and better distinguishing greenness levels in combination with multispectral indices to improve estimates on dry matter.

• Journal of Ginseng Research
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• v.42 no.3
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• pp.304-311
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• 2018

Background: Ginseng black spot disease resulting from Alternaria panax Whuetz is a common soil-borne disease, with an annual incidence rate higher than 20-30%. In this study, the bacterial strains with good antagonistic effect against A. panax are screened. Methods: A total of 285 bacterial strains isolated from ginseng rhizosphere soils were screened using the Kirby-Bauer disk diffusion method and the Oxford cup plate assay. We analyzed the antifungal spectrum of SZ-22 by confronting incubation. To evaluate the efficacy of biocontrol against ginseng black spot and for growth promotion by SZ-22, we performed pot experiments in a plastic greenhouse. Taxonomic position of SZ-22 was identified using morphology, physiological, and biochemical characteristics, 16S ribosomal DNA, and gyrB sequences. Results: SZ-22 (which was identified as Brevundimonas terrae) showed the strongest inhibition rate against A. panax, which showed 83.70% inhibition, and it also provided broad-spectrum antifungal effects. The inhibition efficacies of the SZ-22 bacterial suspension against ginseng black spot reached 82.47% inhibition, which is significantly higher than that of the 25% suspension concentrate azoxystrobin fungicide treatment (p < 0.05). Moreover, the SZ-22 bacterial suspension also caused ginseng plant growth promotion as well as root enhancement. Conclusion: Although the results of the outdoor pot-culture method were influenced by the pathogen inoculum density, the cropping history of the field site, and the weather conditions, B. terrae SZ-22 controlled ginseng black spot and promoted ginseng growth successfully. This study provides resource for the biocontrol of ginseng black spot.

• Journal of Environmental Impact Assessment
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• v.20 no.3
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• pp.381-395
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• 2011

Present work aims to establish an integrated management system of environmental data base for nine typical wind holes or air holes in Korea. It basically deals with definition, geographical distribution, morphological pattern, physical characteristics and anthropogenic environments of wind hole to propose systematic preservation strategy of their periglacial landscape and flora, which are known to be sensitive to global warming. Wind hole, in which cool air blows out during the summer, but mild air comes out during the winter from a cave or hole, is frequently found on northwest- and north-facing slopes on the terminal point of steep talus, block field, and block stream, and can be categorized into three types, i.e., talus, cave and sink types. Environmental characteristics of nine wind holes are analyzed on the basis of their geology, landform, climate, soil, hydrology, vegetation, road, footpath, land-use, and management system, and relevant DB are prepared. Wind hole areas with unique landscape and ecological values need to be designated as a nature reserve, and zoning of core, buffer, and transitional zones are required for the multi-dimensional preservation of periglacial landscape and ecosystem. Phytogeographical values of glacial relict plants, including mountain cranberry(Vaccinium vitis-idaea) at its global southernmost limit at Bangnaeri wind hole, Hongchon County, Gangwon Province of Korea are discussed in detail as a floristic refugia in connection with climate change during the Pleistocene Epoch and potential in-situ and ex-situ preservation sites in the future.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.13 no.5
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• pp.1-11
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• 2010

It is very difficult to control the expansion of reed at a wetland ecological park due to their aggressive reproduction capability. Therefore, proper topography and wetland hydrology should be provided before the construction of a wetland ecological park. Appropriate measures should be taken at the initial stages to prevent reed expansion. Field experiments were conducted at the newly constructed wetland ecological park for 15 months to develop methods to control the reproduction and expansion of Phragmites communis. A complete shading method had the best effect on the prevention of reed reoccurrence among other methods. Complete removal of the rhizomes controlled the reed growth to a greater extent than cutting the aboveground shoots. Water-level manipulation was also better than a half-shading method for the prevention of reed reproduction. These results indicated that soil properties and edge effects can influence the reed growth. Cutting only the aboveground shoots facilitates the growth of reed. These results suggest that reed control should be implemented repeatedly and an alteration in the wetland topography and hydrology may be more effective in the long term. Combination of treatments such as water-level management with shading should be considered to control the growth of reed. Adoptive management for created or restored ecosystem might be considered for accomplishment of its original purpose.

• Korean Journal of Environmental Agriculture
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• v.23 no.4
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• pp.197-202
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• 2004

The persistence of pendimethalin in soil and ground water has an injurious effect on ecosystem. Pendimethalin-degrading bacterium was isolated from Masan, Gyeongnam province and temporarily identified as Bacillus sp. MS202 by the analysis of API CHB50, kit, FAME, and 16S rDNA sequence. from the analysis of pnedimethalin metabolite using TLC, GC, and GC-MS, we found that the degradation of pendimethalin by Bacillus sp. MS202 did not result in the dealkylated form, but the formation of the reduced compound, 6-amino-2-nitro-N(1-ethylpropyl)-3,4-xylidine or 2- amino-6-nitro-N(1-ethylpropyl)-3,4-xylidine.

• Korean Journal of Environmental Agriculture
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• v.30 no.3
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• pp.346-356
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• 2011

BACKGROUND: Chemical fungicides not only may pollute the ecosystem but also can be environmentally hazardous, as the chemicals accumulate in soil. Biological control is a frequently-used environment-friendly alternative to chemical pesticides in phytopathogen management. However, the use of microbial products as fungicides has limitations. This study isolated and characterized a three-antifungal-enzyme (chitinase, cellulase, and ${\beta}$-1,3-glucanase)-producing bacterium, and examined the conditions required to optimize the production of the antifungal enzymes. METHOD AND RESULTS: The antifungal enzymes chitinase, cellulase, and ${\beta}$-1,3-glucanase were produced by bacteria isolated from an sawmill in Korea. Based on the 16S ribosomal DNA sequence analysis, the bacterial strain AM50 was identical to Streptomyces sp. And their antifungal activity was optimized when Streptomyces sp. AM50 was grown aerobically in a medium composed of 0.4% chitin, 0.4% starch, 0.2% ammonium sulfate, 0.11% $Na_2HPO_4$, 0.07% $KH_2PO_4$, 0.0001% $MgSO_4$, and 0.0001% $MnSO_4$ at $30^{\circ}C$. A culture broth of Streptomyces sp. AM50 showed antifungal activity towards the hyphae of plant pathogenic fungi, including hyphae swelling and lysis in P. capsici, factors that may contribute to its suppression of plant pathogenic fungi. CONCLUSION(S): This study demonstrated the multiantifungal enzyme production by Streptomyces sp. AM50 for the biological control of major plant pathogens. Further studies will investigate the synergistic effect, to the growth regulations by biogenic amines and antifungal enzyme gene promoter.

• Korean journal of applied entomology
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• v.60 no.4
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• pp.417-422
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• 2021

This study aimed to provide information on the biodiversity of various arthropods living in paddy fields during the winter season by examining their incidence density. Insect collection was carried out by 50 × 50 cm grids of soil surface and plants from paddy fields, as well as from ridges between paddies, using a battery-powered aspirator. The total number of individuals collected from paddy fields and inter-paddy ridges was 41,197, most of belonged to the orders Collembola, Hemiptera, and Diptera. Arthropods showed similar appearance patterns in fields under both organic and conventional farming. However, a higher number of insects was collected in organic farms. The species diversity, species richness, and species evenness were all greater in inter-paddy ridges than in paddy fields, in a statistically significant manner (P < 0.05).