%0 Journal Article
%T Impact of Maize Formulated Herbicides Mesotrione and S-Metolachlor, Applied Alone and in Mixture, on Soil Microbial Communities.
%A Pierre Joly
%A Pascale Besse-Hoggan
%A Fr¨¦d¨¦rique Bonnemoy
%A Isabelle Batisson
%A Jacques Bohatier
%A Clarisse Mallet
%J ISRN Ecology
%D 2012
%R 10.5402/2012/329898
%X In order to reduce the amounts of pesticides used, and thereby their associated risks, new generations of less environmentally dangerous molecules with lower weight are currently being used in the mixtures sprayed on crops. Few studies have been made, however, to analyse their impact on the soil, and more particularly on the microorganisms living in the soil which maintain the essential functions of this ecosystem. By taking a microcosmic approach, we were able to assess the impact of the maize herbicides ¡°cocktail¡± Mesotrione and S-metolachlor on global soil microbial activity, biomass, and structures, by using the formulated compounds, respectively, Callisto and Dual Gold (both registered brands of Syngenta). Our results highlighted a synergetic effect in ¡°cocktail¡± microcosms resulting in an increase in the Mesotrione herbicide dissipation time and in an impact on the microbial community at onefold field rate equally to more than a single herbicide used at tenfold field rate. 1. Introduction For several decades herbicides have been used in spray form to reduce unwanted vegetation in crops. However, the main indirect casualty of these pesticides, following their spraying, is the soil, and, more particularly, the microorganisms it contains which are essential to maintain the functions of the soil ecosystem [1, 2]. So nowadays, European laws are converging to reduce the amounts of pesticides (Directive Cadre sur l¡¯Eau 2000/60/CE, http://www.eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:32000L0060:fr:html. Directive Cadre sur les pesticides 91/414/CEE, http://www.eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:31991L0414:fr:html. Plan Ecophyto 2018, http://www.agriculture.gouv.fr/ECOPHYTO-2018/) used, and, in doing so, reduce their associated risks. The lack of controls in pesticides targets has caused the revaluation of many first-generation molecules and their replacement with new generations of molecules with lower weight, which, therefore, are less dangerous to the environment [3]. To ensure the efficiency of these new pesticides, the trend is to multiply the molecules used for the same crop in combinations called ¡°cocktails.¡± Unfortunately, comparing to data on single pesticides (e.g., [1]), there are few studies concerned with the impact of these ¡°cocktails¡± on the environment, particularly regarding their indirect impact on soil microbial communities. Some studies [4, 5], however, showed that when two herbicides were used simultaneously, their persistence in the soil was generally prolonged, and the environmental contamination
%U http://www.hindawi.com/journals/isrn.ecology/2012/329898/