Removal of Cd from actual soils polluted with Cd and Zn and Cd-added soils by Brassica juncea and Zea mays
2004
Inoue, H. (Kyushu Univ., Fukuoka (Japan). Biotron Inst.) | Saeki, K.
We have alternated the 3-week cultivation of corn (Zea mays L.) and that of Indian mustard (Brassica juncea (L.) Czern) in a pot with the sequential rotation, corn-Indian mustard-corn-Indian mustard, in order to remove Cd from two actual soils polluted with Cd and Zn, one (low Cd polluted (LP) containing 6.5mg Cd kg sup(-1) and 715mg Zn kg sup(-1) and another (high Cd polluted (HP) with 13.6 mg Cd kg sup(-1) and 836 mg Zn kg sup(-1). Fertilizer applications to soil in a rotational cropping can inhibit the decrease in the phytoextraction efficiency. As the total at the all cultivations, the Cd removal from the soils was 2.1% of the total soil Cd amount in the LP plot and 1.0% in the HP plot. whereas the Zn removal was lower than the Cd cases, 0.57% in the LP plot and 0.17% in the HP plot, respectively. The Cd absorptions by both plants were significantly greater in the metal-added soils than in the actual polluted soils in all cultivations (p<0.05). This would be caused by the high concentrations of exchangeable Cd in the added soils. These results indicated that the use of metal- added sods is likely to overestimate the efficiency of some plants in phytoextraction experiments involving actual polluted soils with its variation by the experimental conditions.
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