Biomass and Bioenergy 21 (2001) 81–90 Dredged sediment as a substrate for biomass production of willow trees established using the SALIMAT technique P.Vervaeke a ; ∗ ,S.Luyssaert a ,J.Mertens a ,B.DeVos b ,L.Speleers c ,N.Lust a a Laboratory of Forestry, Ghent University, Geraardsbergse steenweg 267, 9090 Melle, Belgium b Institute for Forestry and Game Management, Gaverstraat 4, 9500 Geraardsbergen, Belgium c Environmental Research Center, Hekkestraat 51, 9308 Hofstade-Aalst, Belgium Received 19 October 2000; received in revised form 11 January 2001; accepted 6 April 2001 Abstract The periodic dredging of inland waterways and the subsequent disposal of the dredged sediment result in the continuous establishment of contaminated sites. As this dredged sediment is rich in nutrients, occupies extended areas and is often unsuitable for agriculture and public works due to the presence of contaminants, planting energy crops is one option for the remediation of this waste material. To evaluate dredged sediment as a substrate for growing willows, a 20 × 150 m disposal depot was successfully planted using rolls of connected willow rods (SALIMAT). Rods of a Salix fragilis clone and a Salix triandra clone were equally mixed in each mat. This SALIMAT proved to be an economic and eective planting technique for large areas of wet substrate. Leaf nutrient contents were determined to identify potential limiting growth factors Biomass production and tree survival over 4 years of stand development were assessed for three dierent planting spacings (10, 20 and 40 cm). Results of the foliar analyses indicated that both species were supplied with sucient N, P, K and Ca to ensure optimal growth. The introduction of SALIMAT resulted in the rapid development of a high-density fast growing stand characterised by shoot densities of up to 54 shoots= m 2 . An average annual production of 13:4tonDM= ha was measured. The mixture of the two clones did not result in a polyclonal stand as Salix triandra was suppressed by Salix fragilis. The development of a willow stand was unsuccessful on parts of the depot with a sand fraction of 60%. c  2001 Elsevier Science Ltd. All rights reserved. Keywords: Salix fragilis; Salix triandra; Dredged sediment; SALIMAT; Biomass production; Foliar nutrient concentrations; Phytostabilisation 1. Introduction Periodicdredgingofinlandwaterwaysisvitaltoen- sure future navigation but it is a continuous source of * Corresponding author. Fax: +3192525466. E-mail address: pieter.vervaeke@rug.ac.be (P. Vervaeke). large volumes of dredged materials that have to be discarded. Due to poor water management during the recent decades, most ne-grained sediments of the Belgian inland waterways are polluted with contam- inants. The dredged silt is enriched with an excess of nutrients, heavy metals, organic compounds, pes- ticides and pathogens and the disposal results in the 0961-9534/01/$-see front matter c  2001 Elsevier Science Ltd. All rights reserved. PII:S0961-9534(01)00019-8