• The Korean Journal of Mycology
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• v.27 no.2 s.89
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• pp.164-169
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• 1999

This study was carried out in an attempt to select chemicals such as zeolite granules, chitosan, wood-vinegar, $Ca(OCl)_2$, NaOCl, against bacterial brown blotch caused by Pseudomonas tolaasii on Flammulina velutipes in laboratory and mushroom unit. Results obtained using these chemicals were summarized. Inhibitory effect on $Ca(OCl)_2$ and wood-vinegar with 0.5% concentration was shown to caual pathogen, P. tolaasii, by slight damage on the mycelial growth of F. velutipes. Those materials were recognized as promising one for control of bacterial brown bloth on F. velutipes. Disease incidence in control was the highest value as 43.8%; whereas chemical treatment was estimated as 14.6% with 0.5% of $Ca(OCl)_2$. Disease incidence was inhibited about 20% in chemical treatment with 0.5% of wood-vinegar, 1.0% of $Ca(OCl)_2$, and 26.1% with 1.0% of wood-vinegar. For the inhibition effects of chemical concentrations, it was effective at the low concentration which was 0.5% rather than that of 1.0%. Quality of mushrooms was significantly improved, and yields was also increased by 30% in the chemical treatment. In case of $Ca(OCl)_2$ treatment at 1.0% concentration, the yields was increased by 35.6% showed the highest value among tested chemicals. However, the overall effects including disease incidence, quality and yields suggests that $Ca(OCl)_2$ is relatively more effective than wood-vinegar, and the optimal concentration controlling the disease was $0.5{\sim}1.0%$ with $Ca(OCl)_2$ and 0.5% with wood-vinegar.

• Journal of the Mineralogical Society of Korea
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• v.15 no.4
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• pp.329-344
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• 2002

Mineralogical and chemical characterization of some domestic bentonites, such as quantitative XRD analysis, chemical leaching experiments, pH and CEC determinations, were done without any separation procedures to understand their relationships among mineral composition, characteristics, and cation exchange properties. XRD quantification results based on Rietveld method reveal that the bentonites contain totally more than 25 wt% of impurities, such as zeolites, opal-CT, and feldspars, in addition to montmorillonite ranging 30～75 wt%. Cation exchange properties of the zeolitic bentonites are deeply affected by the content of zeolites identified as clinoptilolite-heulandite series. Clinoptilolite is common in the silicic bentonites with lighter color. and occurs closely in association with opal-CT. Ca is mostly the dominant exchangeable cation, but some zeolitic bentonites have K as a major exchangeable cation, The values of cation exchange capacity (CEC) determined by Methylene Blue method are comparatively low and have roughly a linear relationship with the montmorillonite content of the bentonite, though the correlated data tend to be rather dispersed. Compared to this, the CEC determined by Ammonium Acetate method, i.e.‘Total CEC’, has much higher values (50～115 meq/100 g). The differences between those CEC values are much greater in zeolitic bentonites, which obviously indicates the CEC increase affected by zeolite. Other impurities such as opal-CT and feldspars seem to affect insignificantly on the CEC of bentonites. When dispersed in distilled water, the pH of bentonites roughly tends to increase up to 9.3 with increasing the alkali abundance, especially Na, in exchangeable cation composition. However, some bentonites exhibit lower pH (5～6) so as to regard as ‘acid clay’. This may be due to the presence of $H^{＋}$ in part as an exchangeable cation in the layer site of montmorillonite. All the works of this study ultimately suggest that an assesment of domestic bentonites in grade and quality should be accomplished through the quantitative XRD analysis and the ‘Total CEC’measurement.