Impact of phytopharmaceutical products on soil microarthropods in an irrigated maize field: the use of the litter bag method

The effects of two herbicides (atrazine and alachlore) and two insecticides (fipronil and carbofuran) were evaluated on soil mesofauna and organic matter decomposition, in a maize field with normal culture conditions, using the litter-bag method. The litter-bag method was discussed and considered to be adapted for this type of in situ study, especially under normal culture conditions, where it is difficult to find rear control plots. However its adaptability is conditioned by some utilisation factors. The litter-bag colonization and modifications of this colonization by phytopharmaceuticals were interpreted using functional groups classification. Except for alachlore, herbicides appeared to have no differentiated effect on mesofauna. Accordingly, fipronil significantly affects the dynamics of bag colonization by selected groups belonging to soil mesofauna.