ASSESSMENT OF BIOLOGICAL SOIL QUALITY IN LONG-TERM ORGANICALLY MANAGED VINEYARDS IN THE VERDICCHIO TERROIR OF MATELICA (MARCHE, ITALY)

Soil biodiversity constitutes one of the main component of agroecosystems, being involved in the delivery of several essential ecosystem services such as, among others, nutrient cycling, soil formation, pest and pollution control. Thus, soil biodiversity indicators can be used by governments and farmers to monitor soil quality and ecosystem functioning under various land uses and management practices. At present, organic wine represents an emerging market that is showing potential for growth. There is, in fact, a growing worldwide interest and attention for environmental friendly products and sustainable agricultural practices. Organic farming employs a set of farming practices that contribute in preserving soil quality. In this scenario, the aim of our study was to assess the long-term effects of organically managed vineyards on soil quality by means of two bioindicators: ciliated protozoa and microarthropods. Ciliated protozoa are eukaryotic microorganisms which constitutes an essential component of the soil microbial loop. By feeding on bacterial biomass ciliates play an essential role in the liberation of nutrients in the plant rhizosphere. Soil microarthropods contribute to the organic matter degradation and dispersal, affect the soil porosity, aeration, water infiltration, modifying and improving soil fertility. Both ciliates and microarthropods are very sensitive to changes in their habitat and fluctuations in their communities can affect the food web and the energy transfer within the soil ecosystem. Thus, the monitoring of the structure of microarthropod and ciliate communities represent a valuable tool to assess soil quality and functioning. The study was realized in the terroir of “Verdicchio di Matelica” (Marche, Italy), on three vineyards that were organically managed since 1992, 1998 and 2009 respectively. In each vineyard, soil samples (0-10 cm depth) were taken every month from March to October 2011. In addition, soil chemical-physical (texture, soil moisture, pH, NPK, OM, C/N, Cu), were measured in each site. For microarthropods, the measured biological parameters were: the Soil Biological Quality (QBS-ar) index, abundances of biological (BF) and euedaphic forms (EF) and diversity indices. Soil samples were collected in both disturbed (tillage) and not-disturbed (no-tillage) inter-rows. For ciliates: abundances and diversity indices were measured and soil samples were randomly collected in the whole sampling area. The results of the multivariate data analysis (Cluster Analysis, CA; non-metric Multi-Dimensional Scaling, nMDS) and diversity indices (H’,J,d) indicate that the most stable habitat for ciliates and microarthropods is represented by the “older” (V92) followed by the V98 and the “younger” V09 vineyards. Collectively, the data seem to indicate that the long-term organic management of the soil contributes to global soil quality in vineyards at least in this particular pedoclimatic area and for the investigated bioindicators. Furthermore, this study helps in the definition of possible biotic baseline values to evaluate soil quality and health in vineyards.