Numeric variations of soil coleoptera in a strawberry crop under organic and conventional fertilization.

Soil coleopterofauna provides useful information to know and evaluate the kind of agronomic practices carried out in the different agroecosystems. In this paper the taxonomic composition of soil Coleoptera in a strawberry crop under inorganic (nitrogen- phosphorum - potassium) and organic (chicken-bed) fertilization was evaluated. Sampling of soil beetles was carried out using classical pitfall traps. The number of beetles was significatively greater in the organic treatment. Both treatments shared 80 % of the families found. Families Aphodiidae and Elateridae, with mostly detritivorous- phytophagous habits, were significatively predominant in the chicken-bed treatment. The families Carabidae and Staphylinidae, mostly predaceous, with a minor number of fhytophagous- omnivorous species, showed differences in their taxonomic compositions in both treatments. The presence of manure and vegetal debris favoured the presence of same coleopteran families related with decomposition of organic matter. Changes due to modifications of the upper stratum of the soil favoured the cursorial and feeding activities of some coleopteran species.

Key words: Carabidae, pitfall traps, abundance, feeding activities.