Performance of three cultivars of kenaf (Hibiscus cannabinus l.) in zinc and chromium contaminated soils

Soils contaminated with heavy metals can contribute significantly to desertification, loss of ecosystem services, and high levels of heavy metals in the soil are determinants of growth, crop productivity and biomass quality. Production of Kenaf in soils contaminated with heavy metals has been the subject of discussion in several forums, since this crop shows some suitability for phytoremediation, and the biomass being produced can still present an economical aggregated value. Therefore, this study aimed to evaluate the performance of three kenaf cultivars in soils contaminated with Zinc and Chromium. The study was performed in a pot essay and the plants were tested in clay soils. 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; Cr: 300 mg/kg. Results showed that the three cultivars were affected by soil contamination. Hong-Zong was only affected by Cr and not by Zn. In the case of Funong 992, both metals affected the yield, but Cr more than Zn, although differences were not statistically significant. With H328, both metals affected the yields and no significant differences were observed among Cr and Zn effect. In Zn contaminated soils Hong-Zong and Funong 992 cultivars performed significantly better than H328 cultivar. In Cr contaminated soils, Funong 992 cultivar performed significantly better than Hong-Zong cultivar or H328 cultivar. Funong 992 showed to be the best cultivar to crop in Zn or Cr contaminated soils once to both metals, the yields were the highest.