Effect of inorganic and organo-mineral fertilizers on the uptake of selected heavy metals by Helianthus annuus L. and Tithonia diversifolia (Hemsl.) under greenhouse conditions

Abstract

A greenhouse experiment was conducted to assess the removal of lead (Pb), copper (Cu), and cadmium (Cd) from polluted soils using Helianthus annuus and Tithonia diversifolia. There were three pot trials consisting of different levels of Pb and Cu at 0, 125, 250, 500, 1000, 2000 mg kg−1; and Cd at 0, 20, 40, 60, 80, 100 mg kg−1 rates using soluble compounds of (CH3COO)2Pb·3H2O, Cu(NO3)2·3H2O, and CdSO4·8H2O, respectively. Each heavy metal was replicated three times in Completely Randomized Design (CRD) with four different fertility application levels, namely: 300 kg ha−1 of NPK 20-10-10, (Inorganic Fertilizer); 10 t ha−1 of Grade A organo-mineral fertilizer (compost amended with additional N and P), control 1, without fertilizer application and control 2, where no fertilizer and no crop but heavy metals were applied. Pre- and post-cropping analyses of soils used were done. Data were analyzed using ANOVA. From the greenhouse experiment, highest remediated values of 0.83, 0.68, and 0.26 mg kg−1 in the shoots of H. annuus for Cu, Pb, and Cd, respectively, were obtained when organo-mineral fertilizer was applied. Significantly (p < 0.05) lower values of 0.50, 0.43, and 0.25 mg kg−1 of Cu, Pb, and Cd, respectively, were obtained with inorganic fertilizer application. Tithonia diversifolia shoots uptake were 0.20, 1.37, and 0.30 mg kg−1 for Cu, Pb, and Cd, respectively, when OMF was applied. Significantly (p < 0.05) lower values were obtained with inorganic fertilizer applications in the shoot of T. diversifolia. Helianthus annuus remediated Cu and Cd better with organo-mineral fertilizer application while T. diversifolia remediated Pb better also with organo-mineral fertilizer application.