Characterization and growth response of bacteria in soil following application of carbofuran
作者:
DanielE. Edwards,
RobertJ. Kremer,
ArmonJ. Keaster,
期刊:
Journal of Environmental Science and Health, Part B
(Taylor Available online 1992)
卷期:
Volume 27,
issue 2
页码: 139-154
ISSN:0360-1234
年代: 1992
DOI:10.1080/03601239209372771
出版商: Taylor & Francis Group
关键词: enhanced biodegradation;microbial ecology;soil actinomycetes;soil bacteria;soil insecticides
数据来源: Taylor
摘要:
Enhanced biodegradation of carbofuran (2, 3‐dihydro‐2, 2 dimethyl‐7‐benzofuranyl methyl carbamate) is an economically significant, but poorly understood, mlcrobial phenomenon in soil. A series of experiments was conducted to examine short term changes in soil bacterial populations stimulated by carbofuran application at field rates. In the field experiment, commercially formulated carbofuran and butylate (S‐ethyl diisobutyl carbamothioate) were applied at 5.6 kg al ha‐1and 8.4 kg ai ha‐1, respectively, on a soil (Putnam silt loam) exhibiting enhanced degradation of caibofuran. In laboratory studies, technical grade carbofuran (20 mg kg‐1soil) was applied to samples of the field soil. Bacterial populations were estimated using non‐selective (tryptic soy agar) and selective media containing carbofuran or butylate. Largest population increases in pesticide‐treated soil were observed between 7 and 15 days after treatment (DAT) compared to populations in non‐treated soil. Significant increases (P<0.05) in total bacterial populations and presumed carbofuran‐degraders due to carbofuran application were associated with increased populations ofPseudomonasspp. andFlavobacterlumspp. Application of carbofuran appeared to provide a competitive advantage to these species over actinomycetes persisting beyond 20 DAT. Growth responses of bacteria to carbofuran in the Putnam soil were compared to those in a native prairie soil (Mexico silt loam), which exhibited a much slower rate of carbofuran degradation. Bacterial population response to carbofuran was measurable, but small and short‐lived. Perpetuation of the enhanced degradation phenomenon may lie in a persistent pesticide‐induced competitive advantage given to a very small segment of the microbial population. This advantage may not be detectable after 20 days using conventional plating techniques
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