[Effects of acidic soil improvement on active-state Cd content in soil and Cd content in Ligusticum chuanxiong].

Objective: To explore the method to reduce the Cd content in Ligusticum chuanxiong, and to offer the reference for planting Ligusticum chuanxiong with low Cd content.
Methods: A field experiment was carried out to improve the acidic Cd-contaminated soils by different quicklime application, and the effect of quicklime on the percentage of active-state Cd in soil and Cd content in Ligusticum chuanxiong was examined.
Results: Quicklime could reduce the percentage of active-state Cd in soil by increase the acid soil pH value,and as a result, significantly reduce Cd content in Ligusticum chuanxiong. A highly significant negative correlation was found be- tween the Cd content in Ligusticum chuanxiong and quicklime application rate(P =0. 008). Compared with the blank group, Cd content in Ligusticum chuanxiong was reduced by 27. 66%, 24. 87% and 46. 20%, with 750, 1 125 and 1 500 kg/hm2 quicklime application, respectively; while with 1 500 kg/hm2 quicklime application, the soil pH value increased significantly and kept steadily, and the percentage of active-state Cd in soil showed a regular trend which was decreased firstly and increased subsequently.
Conclusion: Cd content in Ligusticum chuanxiong can be reduced significantly by quicklime application,and the effect of high application of quicklime on Cd content in Ligusticum chuanxiong, soil pH values and percentage of active-state Cd in soil is more effective and steady.