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Earthworms are an important component of soil fauna, contributing actively to improve soil structure and fertility. These organisms are highly sensitive to different soil managements and degrees of soil disturbance and were therefore adopted as biomarkers of the soil «health». The Cinturón Hortícola Santafesino (Santa Fe, Argentina) exhibits a large variability in crop species, production systems and working conditions. The aim of this study was to determine the abundance and diversity of earthworms in soils under different types of managements near the villages of Ángel Gallardo and Monte Vera (Dept. La Capital, Santa Fe, Argentina). The three agroecosystems selected were: conventional tillage (LC), notillage with added organic amendments (SDO) and no-tillage (SD). Two samplings were conducted in each field: one in summer and the other in fall of 2008. In addition, some physical and chemical properties of soils were analyzed, as well as the presence of pesticide residues. The density of oligochaetes showed significant differences between seasons and production systems (≤ 0.001). The SDO site had the greatest number of individuals in the two sampled seasons. The taxocenosis consisted of two families: Lumbricidae and Megacolescidae, and three species: Aporrectodea rosea, Aporrectodea trapezoides and Amynthas morrisi. The diversity was low (H'= 0.33), resulting A. rosea the most common and A. trapezoides the most abundant species, respectively. A. trapezoides was incorporated to the earthworm records of the area because it had never been reported in previous studies. The composition and structure of the earthworm's taxonomy is not only affected by the different agricultural practices and the edaphic and environmental conditions, but also by the soil´s physical and chemical properties that influence the oligoquetofauna sensitivity. [ABSTRACT FROM AUTHOR]