• The Plant Pathology Journal
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• v.33 no.3
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• pp.276-287
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• 2017

RcsA is a positive activator of extracellular polysaccharide (EPS) synthesis in the Enterobacteriaceae. The rcsA gene of the soft rot pathogen Pantoea sp. strain PPE7 in Pleurotus eryngii was cloned by PCR amplification, and its role in EPS synthesis and virulence was investigated. The RcsA protein contains 3 highly conserved domains, and the C-terminal end of the open reading frame shared significant amino acid homology to the helix-turn-helix DNA binding motif of bacterial activator proteins. The inactivation of rcsA by insertional mutagenesis created mutants that had decreased production of EPS compared to the wild-type strain and abolished the virulence of Pantoea sp. strain PPE7 in P. eryngii. The Pantoea sp. strain PPE7 rcsA gene was shown to strongly affect the formation of the disease symptoms of a mushroom pathogen and to act as the virulence factor to cause soft rot disease in P. eryngii.

• The Plant Pathology Journal
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• v.29 no.2
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• pp.144-153
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• 2013

Diverse bacteria are known to colonize plants. However, only a small fraction of that diversity has been evaluated for their biopesticide potential. To date, the criteria for sampling and selection in such bioprospecting endeavors have not been systematically evaluated in terms of the relative amount of diversity they provide for analysis. The present study aimed to enhance the success of bioprospecting efforts by increasing the diversity while removing the genotypic redundancy often present in large collections of bacteria. We developed a multivariate sampling and marker-based selection strategy that significantly increase the diversity of bacteria recovered from plants. In doing so, we quantified the effects of varying sampling intensity, media composition, incubation conditions, plant species, and soil source on the diversity of recovered isolates. Subsequent sequencing and high-throughput phenotypic analyses of a small fraction of the collected isolates revealed that this approach led to the recovery of over a dozen rare and, to date, poorly characterized genera of plant-associated bacteria with significant biopesticide activities. Overall, the sampling and selection approach described led to an approximately 5-fold improvement in efficiency and the recovery of several novel strains of bacteria with significant biopesticide potential.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.1081-1089
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• 1996

In Korean agriculture, an automatic environment control system for greenhouse is essential to save labor and to increase the quality of products. The existing environment monitoring systems have weighed on greenhouse growers and researchers because of their high cost and difficult applications. Many sensors are widely used for monitoring the greenhouse environment, but most of commercial sensors are expensive and not suitable for use in greenhouses. Thus , the development of an environment monitoring system for exclusive use in greenhouses is essential . The objective of this study was to develop modular environment monitoring systems, which are low-cost , reliable and easy -to -use. The results showed that the sensors for indoor and outdoor environments and nutrient solution had the ranges and accuracies appropriate for use in greenhouses. Also the modular environment systems developed showed a satisfactory performance in terms of stability and reliability in the measurement and acquisition of the greenhouse environment data.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1999.06a
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• pp.111-135
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• 1999

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.5
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• pp.440-448
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• 2016

Nonpoint sources of pollution (NPS) is defined as diffuse discharges of pollutants (e.g., nutrient, pesticide, sediment, and enteric microorganism) throughout the natural environment and they are associated with a variety of farming practices. Previous studies found that water soluble anionic polyacrylamide (PAM) is one of the highly effective measures for enhancing infiltration, reducing runoff, preventing erosion, controlling nonpoint source of pollutants, and eventually protecting soil and water environment. Potential benefits of PAM treatment in agricultural soil and water environments have been revealed by many research and they include low cost, easy and quick application, and suitability for use with other Best Management Practices (BMPs) for NPS control. This study reviews the various applications of PAM and discusses its further potentials in agricultural environment.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.113-116
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• 2005

Recently the existing environment-friendly method is used in irrigation and drainage canal. So, it is necessary that environment-friendly canal method which is stable and quality. Environment-friendly manufactures which were reflected demand characteristic of drainage and irrigation canal were developed. This study is focused on quality, stability for agricultural district development. According to the results, this method has quaility and economical efficiency, stability and natural characteristic, and will contribute to environment-friendly canal construction.

• Korean Journal of Environmental Agriculture
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• v.38 no.3
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• pp.213-218
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• 2019

BACKGROUND: Monitoring of the dynamic changes of chemical properties in agricultural land is very important for agricultural sustainability. Chemical properties of agricultural soils in Korea have been investigated at four-year interval in the order of paddy, plastic film house, upland, and orchard soils since 1999. METHODS AND RESULTS: Total 8,160 topsoil samples were taken from the upland in 2001, 2005, 2009, 2013, and 2017, respectively. Soil chemical properties such as pH, electrical conductivity (EC), organic matter (OM), available phosphate (Avail. $P_2O_5$), and exchangeable (Exch.) cations (K, Ca, and Mg) were analyzed. Soil pH and Exch. Ca contents have increased since 2001. Average concentration of Avail. $P_2O_5$ increased from $547mg\;kg^{-1}$ in 2001 to $657mg\;kg^{-1}$ in 2017. Average concentration of Exch. Ca in 2017 was higher than the upper limit of its optimal range for upland cultivation. Excess and deficiency of chemical properties of upland soils comply with soil analysis and fertilizer prescription. CONCLUSION: We concluded that excessive nutrient in upland needed to be properly managed with soil test.

• The Korean Journal of Pesticide Science
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• v.14 no.2
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• pp.86-94
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• 2010

This study was conducted to monitor the current status of pesticide residues in agricultural products before auction at whole markets in Busan area from March 2006 to December 2008. Of the 7,237 samples that were analyzed by multiresidue methods, 1,164 samples (16.1%) had pesticide residues and 231 samples (3.2%) exceeded the maximum residue limits (MRLs). 181 samples of the 231 samples exceeding MRLs were applied to the tentative limits because the use of the pesticides for the agricultural products was not established against the MRLs in the Korea Food Code, and it is equivalent to 78.4%. The order of pesticides exceeding MRLs was endosulfan, procymidone, chlorothalonil, ethoprophos, chlorpyrifos, diethofencarb, kresoxim-methyl and EPN. Of 211 samples with two or more pesticides residues, the residues exceeded the MRLs in 80 samples and it is equivalent to 37.9%. This study results suggested that pesticide residues exceeding MRLs could be attributed to the use of inapplicable pesticides for agricultural products and the use of two or more pesticides.

• Korean Journal of Environmental Agriculture
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• v.28 no.1
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• pp.1-8
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• 2009

This study was aimed at assess environmental conservation functions by analyzing the change of land use areas in agricultural fields between 1999 and 2006, and comparing land surface temperature distribution between 1994 and 2006 in Yongin city. Land use maps of Yongin city were obtained from soil maps for 1999, Quickbird satellite images(less than 1 m) and parcel map for 2006. The land use area for Yongin city was in the order of forest > paddy field > upland > residence & building in 1999, and forest > residence & building > paddy field > upland in 2006. Decrease of paddy and upland fields reduced 34% and 41% of the capability of agricultural multifunctionality as to environment including flood control, groundwater recharge, and air cooling. Land surface temperature(LST) was derived from Landsat TM thermal infrared band acquired in September of 1994 and 2006 and classified into three grades. The results impplied that green vegetation in agricultural field and forest play an important role to reduce land surface temperature in warm season.

• The Plant Pathology Journal
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• v.22 no.2
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• pp.174-178
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• 2006

Monacroporium ullum sp. nov. the captures nematodes on adhesive spherical knobs was isolated from soil around Codonopsis lanceolata at Ulleung island, Korea. The spindle-shaped conidia sized $17-44{\mu}m\;(26.5{\mu}m)\;long,\;7-10{\mu}m\;(8.1{\mu}m)$ wide, containing from 1 to 4 cross-walls but most often divided by 2 septa (47%). Resting bodies sized $57{\times}30{\mu}m$. Arthrobotrys amerospora has almost spherical non-septate conidia with a small truncate protuberance at the base and sized $20-27{\mu}m\;(23.3){\mu}m$ long and $11-17{\mu}m\;(14.1){\mu}m$ wide. Conidiophores are somewhat longer $362.8{\mu}m\;(311-418{\mu}m)$ than its original description ($75-250{\mu}m$).