Speciation of soil trace elements in different fumigated soils

Background Soil fumigation is widely used as an effective way to control soil-borne diseases and increase crop yield. Fumigants may also affect the bioavailability and mobility of soil trace elements (STEs) due to the inhibitory and biocidal effects of soil microorganisms. Aims Quantification of STEs fractions after fumigation would help us in understanding the role of fumigants on soil environment and provide valuable evidence on the explanation of the "fertilizer effect" of soil fumigants. The overall objective was to quantify the effects of soil fumigation on three main chemical fractions of nine STEs. Methods Effects of chloropicrin (PIC), dimethyl disulfide (DMDS), dazomet (DZ) on STEs were studied in three soils with standard and high dosages of fumigants. STEs fractions were detected using a modified Community Bureau of Reference three-stage sequential extraction procedure. Results Results were evident in three farmland soils: (1) Among the nine elements, three fumigants had a significant impact on Mn and Co elements. Soils had a great complement to the bioavailable Mn and Co after fumigation. The content of Mn and Co in F1, the most available and transportable form for plants, significantly increased after fumigation with PIC, DMDS, and DZ. (2) Soil fumigation has an impact on Mn, Co, and other trace elements due to the process of Mn oxidation changed. Conclusions Our study suggested that the complement of bioavailable Mn and Co could be an important factor to promote plant growth and increase crop yield after soil fumigation.