不同改良剂对剑麻累积土壤重金属的影响

Effect of Different Amendments on Heavy Metals Accumulation in Sisal

采用盆栽试验,研究在重金属复合污染的土壤中添加改良剂(泥炭、柠檬酸和海泡石)对土壤pH值、镉、铅、锌的有效态含量和剑麻对重金属累积的影响。结果表明:与对照相比,海泡石提高了土壤的pH值,而柠檬酸降低了土壤的pH值,泥炭则对土壤pH值影响不大;3种改良剂均显著降低了土壤有效态重金属的含量,其中,以海泡石降低土壤有效Pb和Zn的效果最佳,其有效态Pb和Zn分别下降了41.44%和30.50%,其次是柠檬酸,其有效态Pb和Zn分别下降了29.50%和26.40%,泥炭处理的土壤有效态Pb和Zn分别下降了26.80%和22.70%;但三种改良剂对土壤有效Cd的影响差异不显著。添加改良剂能改善剑麻的生长,提高剑麻生物量,促进剑麻对重金属的累积,并且以海泡石的改善效果最佳,其生物量达到116.52g/株,分别是添加泥炭、柠檬酸的1.74倍、1.25倍,剑麻对Cd、Pb和Zn的累积量分别是22.51 mg/株、25.44 mg/株和18.06 mg/株。

This study was used to determine the effect of different amendments （peat, citric acid, meerschaum） on soil pH, hevey metals （ Cd, Pb, Zn） availability, and their accumulation in sisal. The results showed that soil pH significantly increased or decreased under meer- schaum application and citric acid, respectively. No significant change was detected in soil pH under peat treatment. All treatments signifi- cantly decreased heavy metals （ Cd, Pb, Zn） availability. Compared with eontrol, meerschaum addition significantly decreased the acid-extractable content of Pb and Zn, in particular, the availability of soil Pb and Zn decreased 41.44 % and 30.50 %, respectively. Citric acid could make the availability of soil Pb and Zn decreased 29.50 % and 26.40 % and the peat make the availability of soil Pb and Zn decreased 26.80 % and 22.70 %. However, effect of amendments on soil Cd availability was not significant. On the other hand, the amendments application promoted sisal growth and increased heavy metals accumulation. The highest plant biomass and heavy metals accumulation was observed in the meerschaum treatment. Plant biomass （116. 52 g/plant） was 0.74 and 0.25 times higher than that of peat and citric acid treatments, respectively. The accumulation of Cd, Pb, and Zn were 22.51,25.44 and 18.06 mg/plant in the meerschaum treatment.