Recycling of river sediments for plant nursery. An experimental study in Europe: CLEANSED - LIFE+ project

River sediment is integral and dynamic part of our river basins but where human activities interfere with sediment quantity or quality, sediment management becomes necessary. Dredging and especially stocking sediments is highly expensive, therefore it would be valuable to find ways to make them a reusable product instead of throwing to landfill. On the other side, there are productive field activities demanding high quantity of soil, such as plant nursing. A European estimation calculates that every year plant nursing consumes about 5,2·106 m3 of soil. So, the purpose of CLEANSED project (LIFE12 ENV/IT/00652) is to use river sediments as plant growing substrates after being decontaminated through phyto remediation technologies. CLEANSED is developed by a community of research organisations located mainly in Tuscany and focuses on the sediments of Navicelli canal, an hydro-way between Pisa and Livorno. After dredging, sediments are stocked in basins and subjected to phytoremediation or landfarming. After phytoremediation process, the sediments are experimented as amendant in soil used for plant nursing: the substrate has to guarantee root development but also soil cohesion of root balls when the plants are extracted for sale. Therefore, the experimental plan aims to test substrates with different percentage of sediments and soil in order to identify the mixture which guarantees the best plant quality. Three ornamental species among bushes and trees, will be planted and physical and chemical properties of the substrates will be compared. . Physiological behavior and stress signals will be monitored during the growing season while plant growth will be measured at the end of the experiment. Eventually, root ball cohesion and the aesthetic appearance (branching, leafage colour) will be evaluated as test for sale. In conclusion, the project team aims to demonstrate that phytoremediation technologies are effective methods to transform river sediment