Effects of Biochar, Arbuscular Mycorrhizal Fungi and Nitrogen Application on Crop(Cichorium intybus L.) Growth and Soil Properties in Cadmium Contaminated Soil

The effects of biochar(BC), arbuscular mycorrhizal fungi(AM), nitrogen(N) and their composite treatments(BC+N,AM+N, BC+AM and BC+AM+ N) application on Cichorium intybus L.(C. intybus L.) nutrient uptake, soil properties and cadmium(Cd) accumulation were investigated in Cd contaminated soil(0.11 mg·kg-1). The results showed that the addition of BC increased the rate of mycorrhizal infection. However, the addition of N slightly inhibited mycorrhizal colonization, and the shoot and root bioaccumulation of chicory was positively influenced by BC and N when inoculated with AM fungi. Compared with the single component treatment(AM, BC or N) or two-component treatment(BC+N, AM+N or BC+AM), the three-component composite treatment(BC+AM+N) had the highest shoot bioaccumulation, whereas BC+AM treatment was considered the best for root biomass bioaccumulation. Compared with the control treatment, the single component treatment(AM, BC or N) and the composite treatment resulted in an overall improvement of the chicory shoot, root related nutrient uptake(N, P, K, Mg, Ca, Mn and Fe) and some soil physicochemical properties; in addition, these treatments showed better results than BC+AM+N and BC+AM treatments. Among the Cd-related indexes, Cd concentrations in the shoot, root and soil of C. intybus L. were reduced through treatment with AM and BC.However, a lower bioconcentration coefficient(BCF) and a higher transfer coefficient(TF) were observed in both treatments, and the most desirable effect was observed following the combination treatment(BC+AM). Compared with other single management,the shoot and root Cd concentrations of C. intybus L. after the management of N alone were higher, and the value of BCF(2.63%)was higher, but the value of TF(1.05%) was lower. Indexes related to Cd improved concurrently following the application of N in combination with BC or AM. Therefore, in Cd contaminated soils, single or combined application of BC, AM and N could promote chicory growth and nutrient uptake and improve some soil physicochemical properties. However, N should not be applied alone and needed to be combined with AM and BC; furthermore, it was evident that the treatment with the three composites(BC+AM+N) was optimal from an application point of view.