Effects of Pesticides on Soil Microflora - Changes in Soil Microflora by Application of Organochlorine Pesticides -

농약(農藥)이 토양미생물상(土壤微生物相)에 미치는 영향(影響) -유기염소계(有機鹽素系) 살균제(殺菌劑) 및 살충제살포(殺蟲劑撒布)에 따른 전토양미생물상(田土壤微生物相)의 변동(變動)-

  • Published : 1984.09.25


The influences of applications of organochlorine insecticide (HCH: Hexachlorocyclohexane, 10 ppm), fungicide (TPN: Tetrachloroisophthalonitrile, 40 ppm) and manure ($3Kg/m^2$) each or together on changes in soil microflora for consecutive years were investigated in the experimental field plots. The insecticide had a little effect on soil microbial numbers. In particular, the number of total bacteria, Gram-negative bacteria and fungi were gradually increased at the latter stage of the consecutive application, but the number of sporeforming bacteria reduced. The fungicide reduced the counts of sporeforming bacteria, actinomycetes and fungi respectively, whereas increased prominently the counts of total bacteria and Gram-negative bacteria. TPN-resistant bacteria, particulary TPN-resistant Gram-negative bacteria were gradually accumulated by the long-term application of TPN, and further the number of TPN-resistant total bacteria and the of TPN-resistant Gram-negative bacteria correlated fairly well during all the period. The influences of combined applications of both HCH and TPN on the number of soil microorganisms were equal to the respective sums of the effects of single application of each pesticide. The combined application of manure and these pesticides elevated the increasing extents of microbial numbers, while weakened the detrimental efforts of these pesticides on microbial numbers. These data suggest that the long-term application of these materials have resulted in the remarkable changes of composition of soil microflora.



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