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AbstractWe report the development of quantitative competitive (QC) PCR assays for quantifying the 16S, 18S ribosomal and atzC genes in nucleic acids directly extracted from soil. QC‐PCR assays were standardised, calibrated and evaluated with an experimental study aiming to evaluate the impact of atrazine application on soil microflora. Comparison of QC‐PCR 16S and 18S results with those of soil microbial biomass showed that, following atrazine application, the microbial biomass was not affected and that the amount of 16S rDNA gene representing ‘bacteria’ increased transitorily, while the amount of 18S rDNA gene representing fungi decreased in soil. In addition, comparison of atzC QC‐PCR results with those of atrazine mineralisation revealed that, in response to atrazine treatment, the amount of atzC gene increased transitorily in soil pre‐treated with atrazine, suggesting that accelerated atrazine biodegradation in soil could be due to a transient increase in the size of the atrazine mineralising community.© 2003 Society of Chemical Industry

AbstractWe report the development of quantitative competitive (QC) PCR assays for quantifying the 16S, 18S ribosomal and atzC genes in nucleic acids directly extracted from soil. QC‐PCR assays were standardised, calibrated and evaluated with an experimental study aiming to evaluate the impact of atrazine application on soil microflora. Comparison of QC‐PCR 16S and 18S results with those of soil microbial biomass showed that, following atrazine application, the microbial biomass was not affected and that the amount of 16S rDNA gene representing ‘bacteria’ increased transitorily, while the amount of 18S rDNA gene representing fungi decreased in soil. In addition, comparison of atzC QC‐PCR results with those of atrazine mineralisation revealed that, in response to atrazine treatment, the amount of atzC gene increased transitorily in soil pre‐treated with atrazine, suggesting that accelerated atrazine biodegradation in soil could be due to a transient increase in the size of the atrazine mineralising community.© 2003 Society of Chemical Industry

AbstractA greenhouse study was conducted to investigate the ability of four crops (wheat, corn, oilseed rape and soybean) to influence the degradation of bentazone, diclofop‐methyl, diuron, isoproturon and pendimethalin in soil. The present study showed that microbial biomass‐carbon was significantly higher in planted soils than in bulk soil, especially with wheat and corn, after several cropping cycles. The biomass in corn and soybean planted soils was adversely affected by bentazone but recovered after three cropping cycles. In wheat‐planted soils, diclofop‐methyl application resulted in persistent increase of the amount of microbial biomass. Bentazone did not show accelerated degradation even after five successive treatments, differing from diclofop‐methyl, for which two applications were sufficient to enhance significantly its rate of degradation. Enhanced degradation of diclofop‐methyl was even more pronounced in wheat‐planted soil. The rates of mineralisation of diuron, isoproturon and pendimethalin were not affected after the first cropping cycle, but were significantly increased in planted soils after five cropping cycles. The results confirm that plants may promote pesticide degradation in soil by stimulating biodegradation processes. In the case of diclofop‐methyl, stimulation of accelerated degradation was observed.© 2002 Society of Chemical Industry

AbstractA greenhouse study was conducted to investigate the ability of four crops (wheat, corn, oilseed rape and soybean) to influence the degradation of bentazone, diclofop‐methyl, diuron, isoproturon and pendimethalin in soil. The present study showed that microbial biomass‐carbon was significantly higher in planted soils than in bulk soil, especially with wheat and corn, after several cropping cycles. The biomass in corn and soybean planted soils was adversely affected by bentazone but recovered after three cropping cycles. In wheat‐planted soils, diclofop‐methyl application resulted in persistent increase of the amount of microbial biomass. Bentazone did not show accelerated degradation even after five successive treatments, differing from diclofop‐methyl, for which two applications were sufficient to enhance significantly its rate of degradation. Enhanced degradation of diclofop‐methyl was even more pronounced in wheat‐planted soil. The rates of mineralisation of diuron, isoproturon and pendimethalin were not affected after the first cropping cycle, but were significantly increased in planted soils after five cropping cycles. The results confirm that plants may promote pesticide degradation in soil by stimulating biodegradation processes. In the case of diclofop‐methyl, stimulation of accelerated degradation was observed.© 2002 Society of Chemical Industry

Global change, in particular climate change, will affect agriculture worldwide in many ways: increased drought or flooding amplitude and frequency, variable temperature increases, loss of natural depuration of waters, soil erosion, loss of soil carbon content, invasion by alien species, increased pest events, changes in plant phenology, increased sensitivity of crops to stress and diseases etc. (Fisher et al. 2005; Howden et al. 2007). These anticipated or even already occurring stresses raise concerns about the sustainability of production and the ability of agriculture to feed human populations. All these changes could lead to an increased use of pesticides (Kattwinkel et al. 2011). Moreover, demographic pressure continues to rise, in particular in tropical and sub-tropical regions, where greater threats to agriculture and food sustainability are anticipated by the Intergovernmental Panel on Climate Change (IPCC) (Easterling et al. 2007). These trends will certainly lead to mounting conflicts involving water uses (irrigation versus drinking water production or freshwater ecosystem maintenance, sanitation etc.) and food production. This appeals to an "ecologically intensive agriculture" (Griffon 2006), i.e. a sustainable agriculture providing ecosystem services more efficiently than today and causing fewer adverse impacts on the environment and water resources. With EU Directive 2009/128/EC (EC 2009a) enforcement, requesting Member States to adopt action plans aiming to reduce risks and impacts related to pesticide uses, there will be a focus in the public and political debates in Europe on achieving a more sustainable use of pesticides. This should consequently lead to a reduction of the risks or impacts of pesticides on the environment. In Europe, there is currently a strong focus on source (including dose) reduction. This approach may nevertheless be too restrictive if the goal is to reduce the agriculture footprint while maintaining or increasing yield. Depending on the chemical properties of pesticides as well as environmental factors, decreasing the amounts of pesticides applied to crops will not automatically produce a decrease in the risk to non-target species or water supply. How could society meet the challenge of the forthcoming climate change? What adaptations should be envisaged for agriculture/pesticide risk management (RM)? These changes will probably have a profound effect on agricultural systems (crop selection, farming practices etc.) and to a lesser extent influence the fate and effects of chemicals (Schiedek et al. 2007). These questions have been addressed by two European research networks, namely Euraqua (the European Network of Freshwater Research Organisations, http://www.euraqua.org/) and PEER (Partnership for European Environmental Research, http://www.peer.eu/), which organised a workshop aiming to identify research needs and strategies induced by these questions in October 2011 in Montpellier, France. The workshop's specific goals were to (1) discuss the pesticide risk assessment (RA) approach, its limitations (e.g.spatial scale and multi-stress situations), the connections between different policies (pesticide regulation and Water Framework Directive), the use of models, (2) review integrated practices and innovative technologies which could or are intended to reduce pesticides' environmental impacts and (3) contribute to the future research and development agenda. This review summarises the workshop discussions.