The degradation rate of atrazine in floodplain soils under natural grasslands and cropped fields in the Liverpool Plains, NSW, was studied under laboratory incubation and in glasshouse bioassays, and related to soil properties including microbial community analysis by t-RFLP. The experiments were part of a broader study aiming to manage pesticides in the environment using vegetative filters (biofilters). The soils differed in their atrazine treatment history. Degradation rate (half-life) in cropped soil was more rapid (≈2 to 7 days) than in 2 grassland soils (≈8 to ≈22 days). Bioassays in the glasshouse using oats and soybeans supported this finding. The t-RFLP analysis disclosed the presence of 2 consortia of bacterial species that are reported in the literature to degrade atrazine. These were: (i) Rhodococcus sp, Pseudomonas aeruginosa, and Clavibacter michiganense and (ii) Acinetobacter sp., Pseudomonas sp., and Streptomyces sp. Their dynamics during incubation suggested that they might have been responsible for the more rapid atrazine degradation in the cropped soil. The enhanced atrazine degradation in cropped soil was also associated with lower concentrations of soil organic C and percentage of light fraction carbon compared with grassland soils, suggesting that atrazine provided an additional source of N and C to organisms that can quickly degrade the herbicide. The finding of relatively short atrazine half-life has implications for the effectiveness of the herbicide, as well as for the loads of pesticide potentially entering the environment. The results suggest there is little risk of atrazine accumulating in biofilters and causing damage.
The aim of the current study was to evaluate the influence of conventional and organic growing conditions on the total phenolic content, the total flavonoids content, the total monomeric anthocyanins content and the antioxidant potential in the apple fruits of Florina variety. The samples were grown and collected from the experimental fields, around Plovdiv and the village of Brestnik. The total phenolic content, the total flavonoids, the total monomeric anthocyanins content were determined. The antioxidant potential was evaluated by four different assays. The apple fruits grown under organic conditions contained higher total phenolics and they showed stronger antioxidant activity than fruits from the conventional conditions. The total phenolic content was from 3 to 5 mg gallic acid equivalent/g dry weight. The total flavonoids were below 1 mg quercetin equivalents/g dw. In the organically grown fruits, the average values for antioxidant activity varied from 30 to 100 mM Trolox® equivalent/g dw. The total monomeric anthocyanins in the organically grown apples their levels were the highest (67 mg cyn-3-glc/100 g dw). There was a positive, high correlation between antioxidant methods and the total phenolic content and total monomeric anthocyanins. These results indicated that organically grown apples accumulated higher levels of antioxidants and bioactive compounds, in comparison to conventionally grown apples.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.