Effects of intercropping and accompanying anion fertilizer on Cd uptake by Brassica campestris L.

To explore more promising ways improving the efficiency of phytoremediation of cadmium (Cd) contaminated soils, a pot culture experiment was conducted to study the impacts of accompanying anion fertilizer and chickpea intercropping on rape growth, Cd uptake and accumulation in soils containing 10.0 mg·kg 1. The results showed that in monoculture rape system, the order of soil DPTA extractable Cd content under different accompanying anion fertilizers was C₁^- > NO₃^- > SO₄^2- > non-accompanying anion. Intercropping with chickpea increased soil DPTA extractable Cd content, and the effects were significant under accompanying anion fertilizers of C₁^- , NO₃^- and SO₄^2- . In monoculture rape system, the order of rape taproot length under different accompanying anion fertilizers was NO₃^- > C₁^- > SO₄^2- > non-accompanying anion, that of rape root volume was SO₄^2- > NO₃^- > C₁^- > non-accompanying anion, it was NO₃^- > SO₄^2- > C₁^- > non-accompanying anion for rape root activity. Intercropping with chickpea significantly increased rape taproot length and root volume under non-accompanying anion fertilizer, and increased root activity under non-accompanying anion fertilizer, and SO₄^2- , NO₃^- accompanying fertilizers. In monoculture rape system, accompanying anions fertilizers significantly increased rape shoot Cd content, with C₁^- accompanying fertilizer presented highest Cd content (470.4 μg·plant^-1). Intercropping with chickpea increased rape shoot Cd content, especially under C₁^- accompanying fertilizer, which reached 783.7 μg·plant^-1. The transfer coefficient of Cd was increased under SO₄^2- , NO₃^- accompanying fertilizers, and it was higher than 1 under all accompanying fertilizers in rape monoculture system. Intercropping with chickpea enhanced transfer coefficient under all accompanying fertilizers. Thus in using rape as phytoremediation plant, the application of C₁^- accompanying fertilizer with chickpea intercropping was a more effective measure for prompting remediation efficiency of Cd contaminated soils.