生物炭质量分数对Cd污染紫色土壤修复的影响

Effect of Biochar Mass Fraction on Cd Contaminated Purple Soil Remediation

为研究不同质量分数生物炭对Cd污染紫色土壤修复效果的影响,通过盆栽种植小白菜,以盆栽紫色土壤(添加外源Cd)为研究对象,未添加外源Cd的紫色土为对照,考察45 d内0、0.5%、1%、3%、5%生物炭质量分数对镉污染土壤修复效果的影响。结果表明:45 d后,当生物炭质量分数为0.5%、1%、3%、5%时,与空白(0)相比,土壤p H值升高了0.16~0.33,有机质升高了0.31~2.55 g·kg^(-1),酸提取态下降了6%~9%,5%的生物炭质量分数对提升土壤p H、有机质,减少有效态Cd效果最好;生物炭质量分数为0.5%、1%、3%、5%时,小白菜生物量先增大后减小,当质量分数为1%时,生物量最高;小白菜地下部分Cd降低了0.169~0.324 mg·kg^(-1),地上部分Cd降低了0.004~0.197 mg·kg^(-1),5%质量分数生物炭时降低最多。综合以上指标来看,5%的生物炭添加量对镉污染紫色土壤的修复效果最好。

In order to study the effect of different mass fraction of biochar on the remediation effect of Cd-contaminated purple soil, bok choy was planted in pots. The potted purple soil(added with exogenous Cd) was used as the research object, and the purple soil without exogenous Cd was used as a control, the investigation was conducted within 45 days. The effect of 0, 0.5%, 1%, 3%, 5% biochar mass fraction on the remediation effect of cadmium contaminated soil was analyzed. The results showed that, after 45 days, when the biochar mass fraction was 0.5%, 1%, 3%, 5%, compared with the blank(0), the soil pH value increased by 0.16~0.33, and the organic matter increased by 0.31~2.55 g·kg^(-1), acid extraction state Cd mass fraction decreased by 6%~9%, 5% biochar dosage had the best effect on increasing soil pH, organic matter, and reducing effective Cd mass fraction;biochar mass fraction was 0.5%, 1%, 3% and 5%, the biomass of pakchoi increased first and then decreased. When the mass fraction was 1%, the biomass was the highest;the Cd mass fraction of the underground part of pakchoi decreased by 0.169~0.324 mg·kg^(-1),and the Cd mass fraction of the above-ground part decreased 0.004~0.197 mg·kg^(-1), the decrease was the most at 5%biochar mass fraction. Based on the above indicators, 5% biochar addition had the best remediation effect on cadmium-contaminated purple soil.