[Effects of Kochia scoparia-Brassica rapa rotation on Cd uptake by Brassica rapa]

In this study, pot and field experiments were conducted to study the enrichment of soil cadmium by Kochia scoparia. Further, rotations in pot experiments were carried out with four varieties of Brassica rapa to verify the remediation effect of Kochia scoparia on cadmium contamination in soil. The enrichment capacity of Kochia scoparia was leaf > root > stem with bioconcentration factors (BCFCd) of 15.07, 5.44 and 2.96, respectively. The total cadmium in soil decreased by 6.02% to 13.60% after planting Kochia scoparia, and the activities of soil urease and acid phosphatase also increased. The results of pot cultivation shows that the above-ground cadmium content of Brassica rapa in Kochia scoparia-Brassica rapa rotation system decreased by 17.21% on average compared with the control group without rotation, whereas the biomass increased slightly, and the above-ground translocation factors (TFCd) did not change significantly. These results suggest that the rotation of Brassica rapa with Kochia scoparia could increase the yield of Brassica rapa, and effectively reduce the cadmium content in edible parts of Brassica rapa, toward the purpose of realizing the green agricultural concept of "harnessing while producing".