谷壳生物炭与石灰石组配对土壤中Cd有效性的影响

Effects of Combined Amendment(Biochar and Limestone) on Availability of Cd in Soil

通过水稻盆栽实验,研究了不同添加量的组配改良剂谷壳生物炭和石灰石(TS)对Cd污染土壤的修复效果及水稻对Cd吸收累积的影响。结果表明:(1)添加TS(2~4 g kg^(-1))能显著提高土壤pH值,与对照相比,Cd含量为0.5 mg kg^(-1)和5.0 mg kg^(-1)土壤pH值分别增加了0.69~1.38和0.70~1.12个单位;(2)TS能显著降低土壤中Cd的生物有效性,在Cd含量为0.5 mg kg^(-1)和5.0 mg kg^(-1)土壤中,添加量为2~4 g kg^(-1)时,能使Cd的Ca Cl2提取态含量分别降低13.3%~86.7%和12.2%~73.6%,使Cd的TCLP提取态含量分别降低52.9%~76.5%和37.1%~76.8%;(3)添加TS(2~4 g kg^(-1))能显著降低水稻根系、秸秆、糙米对Cd的吸收累积,在2种不同Cd含量的土壤中(0.5 mg kg^(-1)和5.0 mg kg^(-1)),使糙米Cd含量分别降低了40.8%~60.0%和49.9%~86.6%,糙米Cd含量低于国家食品卫生标准0.2 mg kg^(-1)的限制。

Pot experiments of rice-planting were conducted to study the effects of combined amendment of biochar and limestone（TS） on the bioavailability of Cd in soil and the uptake and bioaccumulation of Cd of plant（root,straw,and brown rice） of rice plant.The results showed that：（1） Combined amendment of TS（2-4 g kg^-1） significantly increased soil pH values.Compared with control soil（0 g kg^-1）,the pH values increased by 0.69-1.38 and 0.70-1.12 units in the two treatments,in which the concentrations of Cd were 0.5 mg kg^-1 and 5.0 mg kg^-1 soil,respectively.（2）Combined amendment of TS reduced bio-availability of Cd.The concentrations of Cd extracted by Ca Cl2 reduced by13.3%-86.7% and 12.2%-73.6% in the treatments of 0.5 mg Cd kg^-1 soil and 5.0 mg Cd kg^-1 soil,respectively;the concentrations of Cd extracted by the toxicity characteristic leaching procedure（TCLP） reduced by 52.9%-76.5%and 37.1%-76.8%,respectively.（3） Combined amendment of TS significantly reduced the uptake and bioaccumulation of Cd in various tissues of rice plant（root,straw,and brown rice）.The concentration of Cd in brown rice decreased by 40.8%-60.0% and 49.9%-86.6% in these two treatments（Cd 0.5 mg kg^-1 and 5.0 mg kg^-1 soil）,respectively.The concentration of Cd in brown rice was lower than 0.2 mg kg^-1,which is the requirement of national food sanitary standards（GB 2762-2012）.