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设施栽培土壤重金属Cd污染问题备受关注,为阐明生物炭对设施栽培土壤重金属Cd污染的修复效果,试验设置B0(0 t/hm2)、B10(10 t/hm2)和B20(20 t/hm2)3个生物炭水平,研究施用生物炭对土壤Cd形态、生物有效性以及含量的影响。结果表明:生物炭施用显著增加土壤p H和有机质含量,改变了土壤Cd的形态分布,氧化态、有机结合态和残渣态含量增加,交换态Cd含量显著降低。随着生物炭施用量的增加,土壤固定Cd的速率会增加,土壤中有效态Cd的含量发生变化,与对照相比,B10降低土壤有效态Cd 45%~62%,而B20可降低66%~89%。另外,试验还表明,生物炭对Cd污染较轻的大棚土壤有效态Cd的固定效果要好于Cd污染严重的大棚土壤。因此,生物炭可以改变大棚土壤Cd形态,降低土壤Cd的生物有效性,但对受Cd污染严重的设施栽培土壤的修复效果不好。
In order to elucidate the effect of biochar on the Cd pollution in soils cultivated in soils, B0 (0 t / hm2), B10 (10 t / hm2) and B20 (20 t / hm2) ) Three biochar levels to study the impact of biochar application on soil Cd form, bioavailability and content. The results showed that the biochar application significantly increased the content of soil organic matter and p H, and changed the distribution of Cd in the soil. The content of oxidized, organic and residual fractions increased while the content of exchangeable Cd decreased significantly. With the increase of biochar application rate, the rate of fixing Cd in soil increased, and the content of available Cd in soil changed. Compared with the control, B10 reduced the soil available Cd by 45% -62%, while B20 decreased by 66% ~ 89%. In addition, the experiment also showed that biochar was more effective in immobilizing the available Cd in the greenhouse with less Cd pollution than in the greenhouse with Cd pollution. Therefore, biochar can change the form of Cd in greenhouse soils and reduce the bioavailability of Cd in soils. However, the effect of biochar in remediation of soils with facilities contaminated by Cd is not good.