%A Bao Jiang, Dechun Su, Xiaoqing Wang, Jifang Liu, Yibing Ma %T Field evidence of decreased extractability of copper and nickel added to soils in 6-year field experiments %0 Journal Article %D 2018 %J Front. Environ. Sci. Eng. %J Frontiers of Environmental Science & Engineering %@ 2095-2201 %R 10.1007/s11783-017-0990-y %P 7- %V 12 %N 2 %U {https://journal.hep.com.cn/fese/EN/10.1007/s11783-017-0990-y %8 2018-04-15 %X

Long-term decrease in added Cu and Ni toxicity was easily identified in neutral soil.

Extractability as an aging indicator of Cu and Ni is better than phytotoxicity.

In neutral and alkaline soil Cu is extractable more than Ni.

In acidic soil extractability of Cu is similar to Ni.

The phytotoxicity of added copper (Cu) and nickel (Ni) is influenced by soil properties and field aging. However, the differences in the chemical behavior between Cu and Ni are still unclear. Therefore, this study was conducted to investigate the extractability of added Cu and Ni in 6-year field experiments, as well as the link with their phytotoxicity. The results showed that the extractability of added Cu decreased by 6.63% (5.10%–7.90%), 22.5% (20.6%–23.9%), and 6.87% (0%–17.9%) on average for acidic, neutral, and alkaline soil from 1 to 6 years, although the phytotoxicity of added Cu and Ni did not change significantly from 1 to 6 years in the long term field experiment. Because of dissolution of Cu, when the pH decreased below 7.0, the extractability of Cu in alkaline soil by EDTA at pH 4.0 could not reflect the effects of aging. For Ni, the extractability decreased by 18.1% (10.1%–33.0%), 63.0% (59.2%–68.8%), and 22.0% (12.4%–31.8%) from 1 to 6 years in acidic, neutral, and alkaline soils, respectively, indicating the effects of aging on Ni were greater than on Cu. The sum of ten sequential extractions of Cu and Ni showed that added Cu was more extractable than Ni in neutral and alkaline soil, but similar in acidic soil.