Successive soil treatment with captan or oxytetracycline affects non-target microorganisms

Abstract

Changes in microbial biomass and activity were determined in a sandy-loam soil treated with successive dosages of oxytetracycline (a bactericide) or captan (a fungicide) throughout 98 days of incubation under laboratory conditions. The numbers of culturable bacteria and fungi, total bacterial and fungal biomass (as amounts of phospholipid fatty acids, PLFA), the fungal/bacterial ratio, activities of acid and alkaline phosphatases and urease as well as concentrations of N-NH 4 + and N-NO 3 -were assessed. Both oxytetracycline and captan significantly decreased numbers of culturable bacteria whereas total bacterial biomass (bactPLFA) was not affected. Oxytetracycline did not effect on the fungal biomass, however their numbers were reduced after the first and second time of soil amendment with the bactericide. Conversely, fungal numbers and biomass (PLFA 18:2x6,9) significantly decreased in response to soil treatment with the fungicide. Compared to oxytetracycline, captan significantly decreased activities of acid and alkaline phosphatases. For urease activity, the decreased activity was only observed in the soil after the third dosage of captan. Both biocides significantly increased concentrations of N-NH 4 + and decreased concentrations of N-NO 3 -after the soil treatments. The results of this study indicate that successive soil treatment with oxytetracycline or captan dosages may negatively affect non-target soil microorganisms and their activities.

Effect of insecticides alone and in combination with fungicides on nitrification and phosphatase activity in two groundnut (Arachis hypogeae L.) soils

“…Phosphatases play a crucial role in the phosphorous acquisition of plants and microorganisms and thus in the cycling of it within the soil (Schneider et al 2001). The activities of phosphatases were inhibited in sandy loam soil amended with captan during 94 days of incubation (Piotrowska et al 2008). Residual carbendazim induces negative effect on phosphatase activity (Sousa et al 2004).…”

Soil microbial community structure and microbial activities in the root zone ofNothapodytes nimmoniana

“…The rapid changes in soil microbial community structure as affected by growing plants (Velasco et al 2010), heavy metal pollution (Farrell et al 2010), soil application of fungicides (Minambres et al 2010) and bactericide (Piotrowska-Seget et al 2008), can be detected by changes in PLFA patterns. These results indicated that PLFA analysis can be used for detecting rapid changes in living populations (Zelles 1999).…”

Changes in humus forms and soil N pathways along a 130-year-old pure beech forest chronosequence

“…We used captan (N-(trichloromethylthio)cyclohex-4-ene-1,2-dicarboximide, IUPAC) which is a common nonspecific fungicide with limited non-target effects on soil fungi relative to other fungicides. Captan is a broad-spectrum contact fungicide that has little effect on soil bacteria (Bailey et al 2002).At low concentrations (1 gkg −1 ), captan has few effects on bacterial biomass and activity (Piotrowska-Seget et al 2008).…”