Soil microbial community functioning and structure have been studied on agricultural soils treated with both wood amendments and an herbicide (linuron or terbuthylazine). For this purpose the soil dehydrogenase activity, the number of live bacteria and the phylogenetic structure of the bacterial community by Fluorescence In Situ Hybridization (FISH) were assessed in soil treated with linuron or terbuthyazine and either amended with pine or oak wood or un-amended (sterilized and nonsterilized). Moreover, the ability of specific microbial groups to degrade the herbicides was evaluated in terms of half-lives (t1/2) in the un-amended and amended soils for an incubation period of about 60 days. The overall results showed that the bacterial community had a significant role in herbicide degradation. The herbicides halflives (t1/2) values indicated a slower degradation rate in pine and oak amended soils than in unamended ones. This is attributed to the higher sorption of herbicides by these soils compared to the un-amended ones. Furthermore, these herbicides did not affect the microbial community, presumably because the latter had adapted to its presence. However, the specific activity of the herbicide degrading populations was negatively affected by the amendment owing to a lower bioavailability of the herbicide for microbial degradation.
EFFECTS OF CO-PRESENCE OF HERBICIDES AND WOOD AMENDMENTS ON STRUCTURE AND FUNCTIONING OF SOIL BACTERIAL COMMUNITIES
GRENNI P;BARRA CARACCIOLO A;
2009
Abstract
Soil microbial community functioning and structure have been studied on agricultural soils treated with both wood amendments and an herbicide (linuron or terbuthylazine). For this purpose the soil dehydrogenase activity, the number of live bacteria and the phylogenetic structure of the bacterial community by Fluorescence In Situ Hybridization (FISH) were assessed in soil treated with linuron or terbuthyazine and either amended with pine or oak wood or un-amended (sterilized and nonsterilized). Moreover, the ability of specific microbial groups to degrade the herbicides was evaluated in terms of half-lives (t1/2) in the un-amended and amended soils for an incubation period of about 60 days. The overall results showed that the bacterial community had a significant role in herbicide degradation. The herbicides halflives (t1/2) values indicated a slower degradation rate in pine and oak amended soils than in unamended ones. This is attributed to the higher sorption of herbicides by these soils compared to the un-amended ones. Furthermore, these herbicides did not affect the microbial community, presumably because the latter had adapted to its presence. However, the specific activity of the herbicide degrading populations was negatively affected by the amendment owing to a lower bioavailability of the herbicide for microbial degradation.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
