Production of oil crops under heavy metals contaminated soils

Cultivation of energy crops in heavy metals contaminated soils is an option once it contributes to reduce land use competition with food crops and the development of a vegetative cover contributes to reduce soil loss and degradation by erosion processes and water surface runoff. Therefore, the aim of this work was to study the effects of different heavy metals (Ni, Pb, Zn and Cd) on growth and yield of different energy crops, namely the oil crops Camelina sativa, Brassica carinata and Thlaspi arvense. The soils were artificially contaminated and the concentrations chosen were based on the limits established by the Decree Law 276 of 2009 (Portuguese regulation that establishes the regime for the use of sewage sludge in agricultural soils)-Zn: 450 mg/kg; Pb: 450 mg/kg; Cd: 4 mg/kg and Ni: 110 mg/kg. Preliminary screening of the different crops studied indicate that Brassica carinata and Camelina sativa growth was not significantly affected by heavy metals contamination. By opposition, all the heavy metals affected the growth of Thlaspy arvense. Yet, contamination reduced significantly the number of siliquae, especially Ni and Cd contamination, which may hinder the economical viability of oil crops cultivation in heavy metals contaminated soils. Biomass is being characterized to evaluate the effects of the contamination on the oil characteristics and the phytoremediation capacity of these oil crops to the heavy metals contaminated soils studied.