生物炭施用对污染红壤中重金属化学形态的影响

Effects of the Application of Biochar on the Chemical Fraction of Heavy Metals in Polluted Red Soil

采用BCR分级提取的方法研究了2种不同生物炭施用对污染红壤中重金属Cu、Zn、Cd和Pb化学提取形态的影响.结果表明,生物炭施用提高了土壤pH值和有机质含量.实验土壤中重金属Cu、Zn、Cd和Pb均主要以残渣态存在(分别为86.11%、63.30%、66.24%、50%),施用鸡粪生物炭(P)后Cu、Cd和Pb的可还原态比例降低,Zn可还原态与Cu、Zn、Cd、Pb的酸可提取态和可氧化态的比例都有所增加.施用木屑生物炭(W)后Zn、Cd和Pb的可还原态比例降低,Cu、Zn、Cd和Pb的酸可提取态,Cu可还原态及Cu、Zn可氧化态的比例增加.总体来看,施用木屑生物炭(W)和鸡粪生物炭(P)后,Cu和Zn的残渣态所占比例分别降低了9.3%、27%,3.7%和16%,而Cd和Pb的残渣态比例分别增加了3.6%、3.0%,4.5%和3.7%,表明施用2种生物炭可以增加Cu和Zn的生物有效性,且施用P生物炭后增加的比例大于施用W生物炭;降低Cd和Pb的生物有效性,但施用2种生物炭后降低的比例相差不大.

BCR sequential extraction procedure was applied to examine the effects on the heavy metal （Cu, Zn, Pb and Cd） fractionation in polluted Chinese red soil due to the application of two different biochars, W and P, which derived from poultry litters and wood chips respectively. The results showed that the pH and organic matter content of soil was enhanced by biochars amendment. The typical heavy metals, Cu, Zn , Ph and Cd, mainly existed in the residual fraction （86. 11% ,63.30% ,66.24% ,50%）in red polluted red soil. Compared with the null treatment, the chemical fraction percentage of most heavy metals in the red soil was altered by the amendment of P or W. The amendment of P decreased the percentage of reducible fraction of Cu, Cd and Pb, but increased that of Zn. The amendment of W decreased the percentage of reducible fraction of Zn, Cd and Pb, while increased that of Cu. The amendment of P and W increased the percentage of acid soluble fraction of four heavy metals. W addition just increased the percentage of oxidisable fraction of Cd and Pb, b, owever the amendment of P increased that of four heavy metals. The amendment of W and P decreased the percentage of residual fraction of Cu and Zn, respectively as 9.3%, 27M, 3.7% and 16% % But increased that of Cd and Pb, respectively as a. 6%, a. 0%, 4.5M and 3. 7%. The results indicated that the amendment of W and P can increase the bioavailability of Cu and Zn, the amendment of P were more effective than that of W; The amendment of W and P can decrease the bioavailability of Cd and Pb, but the effects of two different biochars are similar.