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Abstract: The aim of this study was to clarify the potential of soil enzyme activities as indicators of pesticide contamination, and to compare this to using the functional diversity of bacterial communities via Biolog® Ecoplates. The individual effects of the pure active ingredients (i.e. not the commercial formulations) of ten pesticides on various soil enzyme activities were recorded under laboratory conditions at different incubation times (i.e. 0, 2, 6 and 12 months). Results clearly showed that response patterns of soil enzyme activities differed in their sensitivities to pesticide addition over time (i.e. stimulation, inhibition or no effect). Results suggested that phenol oxidase activity could be used as an early indicator of pesticide contamination, and arylamidase and β-glucosidase could be used to evaluate soil resilience after pesticide disturbances. We concluded that the functional diversity of bacterial communities was less efficient than soil enzyme activities as an indicator of pesticide contamination. [Copyright &y& Elsevier]

Abstract: This study under field experimental conditions in apple orchard agroecosystems investigated the effects of pest management strategies (i.e. none, organic, conventional and integrated) on enzyme activities, in relation to soil properties. Enzyme activities chosen are implicated in the major biogeochemical nutrient cycles such as C (cellulase, fluoresceine diacetate hydrolase, β-galactosidase, β-glucosidase, phenol oxidase), N (arylamidase), P (acid and alkaline phosphomonoesterases, phosphodiesterase and phosphotriesterase) and S (arylsulfatase). Redundancy analyses and decomposition of the variances were performed to clarify how enzyme activities are affected by management strategy and soil properties. Results showed that the effects and their proportion attributable to management strategy and soil properties varied considerably depending on enzyme activity. Phenol oxidase activity was the only case where total variance was principally explained by management strategy (i.e. conventional and integrated) rather than by soil properties, and thus it seems to be an attractive potential indicator to assess soil quality in this agrochemical context. [Copyright &y& Elsevier]