Cambios en la presencia de especies de oribátidos (Acarina, Oribatida) asociados a la fertilización con purín porcino en clima Mediterráneo seco

In rainfed agricultural systems, the sustainability of fertilization practices with products of organic origin needs indicators that guarantee their suitability. Oribatid mites, because of their growth characteristics and their function as organic matter transformers, are potential biological indicators. A study on the presence of oribatid mite species in a fertilization experiment (a treatment with pig slurry at a dose of 161 kg N·ha -1 and a control) was carried out. Under a dry Mediterranean climate, the experiment was established twelve years ago. It included a rotation of wheat-barley under rainfed conditions. During the barley’s cropping season (October, March and June), three soil samples were taken for the identification of the number of individuals for the different oribatid species present. Four species were found, but there were no significant differences in diversity or dominance between treatments. However, a significantly higher abundance of oribatids was found in plots with slurry application, linked to a significant increment of Oribatula (Zygoribatula) excavata. The higher presence of this species, with no de-triment to the rest, can be considered a positive indicator regarding the sustainability of this fertilization practice. In other words, it endorses the absence of negative impacts on soil health when the applied slurry rate was below the limit for N of organic origin established in N vulnerable zones.