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Purpose A combined treatment of composting and vermicomposting of poultry litter (PL), rice hulls (RH) and/or eucalyptus sawdust (ES) was carried out in order to obtain a high-quality organic fertilizer and avoid the environmental problems associated with the use of raw poultry manure and fresh agricultural waste materials. Methods Three composting mixtures were made at volume proportions: 1:3 RH/PL (M1); 1:2 ES/PL (M2) and 0.5:1:2 RH/ES/PL (M3). Composting (120 days) followed by vermicomposting (90 days) using earthworms (Eisenia fetida) were conducted during the autumn-winter season, outdoors and sheltered. Moisture content was kept at 60-70%. Physicochemical (pH, electrical conductivity, lignin, total carbon and nitrogen, organic matter, ammonium and specific cations), total microbial activity (fluorescein diacetate hydrolysis) and microbiological parameters were recorded throughout both processes. Phytotoxicity tests were lastly performed by means of Lactuca sativa, L. seed germination, to compare the quality of the organic fertilizers obtained. Results A sequential compost-vermicompost process enhanced the properties of the final products. Particularly, electrical conductivity was markedly lower in all vermicomposts (1.81-2.28 mS cm-1) and within the values recommended for the growth of sensitive plants; microbial activity reached 187.1-203.8 µg FDA gsoil-1 h-1. Germination Index values in vermicomposts were greater than 60%, indicating the high quality of the products obtained, being the mixture 0.5RH:1ES:2PL, the one which showed better quality and higher maturation degree. Conclusion The system that combines both processes (composting+vermicomposting) was effective to produce a stabilized organic fertilizer from poultry litter with other waste organic materials.

Las lombrices de tierra constituyen un componente importante en la fauna del suelo contribuyendo activa y beneficiosamente en su estructura y fertilidad. Estos organismos son sensibles ante distintos manejos y grados de perturbación del suelo respondiendo como bioindicadores de la «salud» del mismo. El Cinturón Hortícola Santafesino (Santa Fe, Argentina) exhibe diferencias no sólo en tipos de cultivos sino también en sistemas de producción y condiciones de trabajo. El objetivo del estudio fue determinar la abundancia y diversidad de la oligoquetofauna en los suelos con distintos tipos de manejo en las localidades de Ángel Gallardo y Monte Vera (Dpto. La Capital, Santa Fe - Argentina). Se seleccionaron tres agroecosistemas: labranza convencional (LC), siembra directa orgánica (SDO) y siembra directa (SD). En cada campo se realizaron dos muestreos, correspondiendo uno a la estación verano y el otro a otoño de 2008. Se analizaron algunas propiedades físicas y químicas de los suelos como también residuos de plaguicidas. La densidad de oligoquetos presentó diferencias por estación y sistemas de producción (p = 0,001) destacándose el sitio de SDO con el mayor número de individuos en las dos estaciones muestreadas. La taxocenosis constó de dos familias: Lumbricidae y Megascolecidae, y tres especies: Aporrectodea rosea, Aporrectodea trapezoides y Amynthas morrisi. La diversidad fue baja (H'= 0,33), siendo A. rosea la especie más común en los sitios muestreados y A. trapezoides la más abundante, incorporándose estaúltima a la lista de oligoquetos para la zona hortícola ya que en estudios anteriores no se hallaba registrada. La composición y estructura de la taxocenosis de lombrices de tierra se ve afectada no sólo por las condiciones ambientales y labores de producción, sino también por los parámetros físicos y químicos del suelo, que en conjunto condicionan la sensibilidad de la oligoquetofauna.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.