A pot culture experiment was conducted at seedling stage to study the effects of 6 kinds of amendments (vermiculite, plant ash, peanut shell-biochar, straw-biochar, sepiolite, sodium humate) applied to yellow soil and red soil on decreasing cadmium content in tobacco leaves. The results showed that comparing with the control, amendments (except for plant ash and sodium humate) reduced the cadmium content in tobacco leaves at different extents; the sepiolite application to yellow soil and red soil showed the best effects, the cadmium content in leaves decreased by 32%-42% and 86%, respectively. Biochar was effective only in red soil, cadmium content in leaves decreased by 31%-52%. The available cadmium content in soil treated with different amendments extremely significantly positively correlated(r=0.95, P<0.01)to cadmium content in tobacco leaves, and the function of cadmium content reduction in tobacco leaves was attributed to the reduction of bioavailability of cadmium in soil caused by amendments. Available cadmium content in soil extremely significantly negatively correlated (r= -0.93, P<0.01)to pH in yellow soil, whereas their relationship was not significant in red soil, which explained the different functional mechanisms of amendments in the two kinds of soil.%采用盆栽试验,利用黄壤与红壤土研究了蛭石、草木灰、花生壳生物黑炭、秸秆生物黑炭、海泡石、腐植酸钠6种改良剂对降低烟叶中镉含量的效果.结果表明,与对照相比,除施用草木灰和腐植酸钠外,其他改良剂均不同程度降低了烟叶中镉含量,以海泡石处理的效果最好,可分别使黄壤和红壤土上栽培的烟叶镉含量降低32％～42％和86％,两种生物黑炭处理仅在红壤中效果较好,可降低烟叶镉含量31％～52％.不同改良剂处理的土壤有效态镉与烟叶中镉含量呈极显著正相关(r=0.95,P＜0.01),改良剂的作用是通过降低土壤中镉的有效性而达到降低烟叶镉含量的效果.土壤pH与土壤有效态镉含量呈负相关关系,但相关程度随土壤性质不同而有所差异,黄壤土的pH与土壤有效态镉含量呈极显著负相关(r=-0.93,P＜0.01),但红壤土中二者关系不显著.说明改良剂在不同类型土壤中的作用机制存在差异.
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