Abstract
The effects of two herbicides (atrazine and alachlore) and two insecticides (fipronil and carbofuran) on organic matter decomposition and soil mesofauna were evaluated in a maize field under normal agriculture conditions. Soil mesofauna were studied using the litterbag method. Near infrared reflectance spectrophotometry was used to study the effects on decomposition parameters (litter mass and nitrogen dynamic). The effects on soil microarthropods varied depending on both taxon and pesticide, with fipronil having a particularly strong effect. Differences were also observed between treatments for organic matter decomposition parameters, especially with the use of alachlore. Therefore, the analysis of microarthropods and the decomposition parameters provides complementary information on the effects of these chemical treatments.