Field Evaluation of Willow Under Short Rotation Coppice for Phytomanagement of Metal-Polluted Agricultural Soils

Abstract

Short rotation coppice (SRC) of willow and poplar might be a promising phytoremediation option since it uses fast growing, high biomass producing tree species with often a sufficient metal uptake. This study evaluates growth, metal uptake and extraction potentials of eight willow clones (Belders, Belgisch Rood, Christina, Inger, Jorr, Loden, Tora and Zwarte Driebast) on a metal-contaminated agricultural soil, with total cadmium (Cd) and zinc (Zn) concentrations of 6.5 +/- 0.8 and 377 +/- 69mg kg1 soil, respectively. Although, during the first cycle, on average generally low productivity levels (3.7 ton DM (dry matter) ha1 y1) were obtained on this sandy soil, certain clones exhibited quite acceptable productivity levels (e.g. Zwarte Driebast 12.5 ton DM ha1 y1). Even at low biomass productivity levels, SRC of willow showed promising removal potentials of 72g Cd and 2.0kg Zn ha1 y1, which is much higher than e.g. energy maize or rapeseed grown on the same soil. Cd and Zn removal can be increased by 40% if leaves are harvested as well. Nevertheless, nowadays the wood price remains the most critical factor in order to implement SRC as an acceptable, economically feasible alternative crop on metal-contaminated agricultural soils.