EFFECT OF TREATED SEWAGE SLUDGE ON THE MINERAL NUTRITION AND PRODUCTION OF ARUNDO DONAX L.

This study aims to evaluate the use of organic amendments from treated sewage sludge to improve Arundo donax L production in experimental plots (5mx 10m) in a calcareous soil in Alcala de Henares (Spain). The use of urban waste as a source of organic matter and nutrients is a valid alternative to retrieve the characteristics of the soil and enhance the crop yield. Because of the residue composition, the potential transfer to the soil of the heavy metals present in the wastes is evaluated. After two growing seasons, plant biomass and mineral nutrition was enhanced in plots treated with urban residues in comparison to mineral fertilizer and control soil. After application of the amendments a slight decrease of pH values and no changes in electric conductivity were observed in plots treated with amendments. In addition, soil organic matter and nutrient content was enhanced. The content of heavy metals in soil treated with urban wastes increased, but in any case the legislative limits were exceeded for soils with pH>7. Given the results obtained, it can be concluded that the application of treated sewage sludge is a good alternative for the production of Arundo in the assayed conditions.