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| Effects of Different Planting Patterns on Concentrations and Migration of Soil Heavy Metals in Dryland in Southern China |
| Received:December 31, 2014 |
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| KeyWord:planting patterns;dryland;maize;soybean;heavy metals;migration |
| Author Name | Affiliation | | WEI Xiang-dong | College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China | | ZOU Hui-ling | Library of Hunan Agricultural University, Changsha 410128, China | | TIE Bai-qing | College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China | | CHEN Huan | College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China | | CAI Dan | College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China | | CAI Lei | College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China | | FANG Ya-yu | College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China | | YIN Xiao-hui | College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China |
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| Abstract: |
| Plant species have different impacts on forms and transformation of heavy metals in soil. Here an experiment was performed to investigate the effects of single and inter-planting of soybean and maize on content, forms and migration of soil heavy metals in dryland in Southern China. Results showed that the content of Pb, Cd and Zn exceeded the second grade levels of the National Soil Environmental Quality Standard(GB 1518-2008). Compared to the soil with single planting, Pb, Zn, Cu, Cd, Fe and Mn concentrations under the interplanting tended to decrease in both rhizospheric and non-rhizospheric soils. However, plating patterns had significant effects on forms of soil heavy metals. The forms of soil heavy metals were significantly different between rhizospheric and non-rhizospheric soils. Residual form was the main fraction of Zn, Cu, Fe and Mn in both rhizospheric and non-rhizospheric soils, accounting for more than fifty percent. The forms of Pb and Cd were significantly different from those of Zn, Cu, Fe and Mn. Oxide bound Pb was the major fraction in both rhizospheric and non-rhizospheric soils, constituting about forty percent in non-rhizospheric soil and about fifty percent in rhizospheric soil. Percentages of exchangeable and carbonate bound Cd were respectively 14.01%~15.82% and 9.56%~9.90% in rhizospheric soil, while 0.63~0.85 and 1.38~1.48 times more in non-rhizospheric soil. The content of Pb, Zn, Cu, Cd, Fe and Mn was significantly different between soybean and maize, and influenced by planting patterns. Lead and Cd in edible part of soybean were 37.95~43.45 and 50.5~52.6 times higher, while in maize 47.2~56.8 and 9.7~15.8 times more than the limits for pollution standard in food(GB 2762-2012), respectively. These results show that food crops planted in the tested field had high health risks and that changing from paddy field to dry land is not an option for remediation of soil contaminated with heavy metals |
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