生物炭对重污染土壤镉形态及油菜吸收镉的影响

Effects of Biochar on Forms and Uptake of Cadmium by Rapeseed in Cadmium-Polluted Soil

为了解不同种类和用量的生物炭对土壤镉形态及油菜吸收镉的影响,通过室外盆栽试验,以湖南某冶炼区周边重镉污染土壤为供试土壤,湘油27号为供试作物,于油菜移栽前7 d分别添加w为0.1%和1%的竹炭和柠条炭,分析土壤镉形态和成熟期油菜各器官镉含量。结果表明,添加生物炭能降低土壤镉的有效性和油菜各器官中镉含量。柠条炭降低油菜吸收累积镉的效果比竹炭更明显,且随着生物炭量的增加阻控效果更明显。相比于对照组,施用生物炭后土壤中w(可交换态镉)最大可降低16.64%;油菜根部、茎秆、油荚和籽粒w(镉)最大可分别降低34.06%、39.74%、33.15%和49.81%。综合结果表明,添加w=1%柠条炭处理组处理效果最佳。

An outdoor pot experiment was conducted to study effects of biochar on Cd form and Cd uptake by rapeseed（ Xiangyou 27） in the heavily Cd polluted soil collected from a field nearby a metal melting plant in Hunan,relative to type and dosage of the biochar. In the pots,caragana biochar or bamboo biochar was amended,separately at a rate of0. 1% and 1%,7 days before rapeseed seedlings were transplanted. Then soil samples were analyzed for Cd forms and rapeseed plants were analyzed for Cd contents in various organs at the mature stage. Results show that amendment of biochar may reduce soil Cd availability and Cd contents in various organs of the plant. The effect of caragana biochar reducing Cd uptake and accumulation by the plant was more obvious than that of bamboo biochar. Moreover,the effect became more obvious with increasing biochar amendment rate. Compared with CK,amendment of biochar reduced the content of exchangeable Cd in the soil by as high as 16. 64%; and decreased the Cd concentrations in roots,stems,hulls and seeds of the rapeseed by as much as 34. 06%,39. 74%,33. 15% and 49. 81%,respectively. In short,Treatment of amendment of 1% caragana biochar is the most effective in the experiment.