Effects of Cd on soil microbial biomass depend upon its soil fraction distribution

Abstract

Partitioning between soil fractions of Cd added to agricultural soil at 50 and 100 mg kg⁻¹ and its effects on soil respiration and microbial biomass were studied for up to 60 days. Initially, Cd was distributed mostly into the exchangeable and carbonate fractions but decreased in the former fraction within 60 days. Cd pollution resulted in decreased basal and substrate-induced respiration by about 25%, and of microbial biomass carbon by about 35%. Soil biological properties were improved during the incubation and they were shown the highest correlations with Cd in bounded to Fe–Mn oxid fraction. It could be because of the lower concentration of this fraction and the sharper changes in it during the incubation as compared to the rest of Cd fractions (especially as compared with exchangeable fraction; more toxic fraction of Cd).

Keywords:

• Cd soil pollution
• Cd in soil fractions
• global soil biological properties

Acknowledgments

The authors thanks from Dr. Hartmut Frank for editing this paper.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The authors wish to express their gratitude to Shahid Chamran University of Ahvaz, Iran, for their financial support for this work [AG1396-3-02-16670 Grant-Faculty of Agriculture].