The Use of River Sediments for Plant Nursery in the Framework of the LIFE+ project CLEANSED

Abstract

Abstract-River sediments are an integral and dynamic part of river basins but where human activities interfere with sediment quantity or quality, their management becomes necessary. Dredging and especially stocking polluted 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 5.2·10 6 m 3 of soil. To address these issues, five Institutions from Italy and one from Spain are involved in the CLEANSED project (LIFE12 ENV/ IT/00652, 2013IT/00652, -2016. One of the aims of the project is to test the use river sediments as plant growing substrates after being decontaminated through phytoremediation technologies. 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. The experimental plan aims to test substrates with different percentage of sediments and alluvial soil in order to identify the mixture which guarantees the best plant quality. From May 2014 to November 2015, three ornamental bush species (Photinia x fraseri var. Red Robin, Viburnum tinus L. and Eleagnus macrophylla L.) were planted into woody frames filled with different percentage of sediments and soil (respectively 0 and 100%, 33% and 66% and 50% and 50%). Physical and chemical properties of the substrates as well as plant growth, physiological behavior and stress signals have been monitored through 2014 and 2015 vegetative season. The aim of this study is to present the setting and some results about plant growth, with a focus on the effect of temperature and substrate on the growth of the investigated species..

Testing decontaminated sediments as a substrate for ornamentals in field nursery plantations

“…In contrast, V. tinus LA in T33 and T50 was greater than in CTL. These results were also confirmed by the height growth rate which resulted similar in all substrates for P. x fraseri and E. macrophylla, while V. tinus grew faster in T50 than in CTL (Massetti et al, 2016). V. tinus was the only species showing significant relationship between growth parameters and soil properties (Table 3).…”

“…Further improvements are needed to achieve standardization in the chemical quality of the soil and to ensure the reliability of the decontamination treatment, and more investigations are needed to assess its suitability for specific types of nursery production. For example, the coarse and loose structure of the remediated sediments could be advantageous in productions that require easy soil removal from the root ball, like plants that need transplanting within the nursery production cycle (Mason, 2004;Jack-Scott, 2012), or for the sale of bare-rooted plants (Hensley, 1993;Bassuk, 2000;Buckstrup and Bassuk, 2000;Yang and McBride, 2003). More attention should be given to determining the extent to which sediments show the best performance, either by enhancing their structural homogeneity e by applying a mechanical treatment e or by mixing different percentages or different alluvial soils.…”