Influence of the application of chelant EDDS on soil enzymatic activity and microbial community structure

The present study evaluated the effects of a biodegradable chelant, S,S-ethylenediaminedisuccinic acid (EDDS), on enzyme activities and microbial community composition in copper (Cu)-contaminated soils, planted with either corn or beans. Results showed that the application of EDDS did not affect urease and acid phosphatase activities in the soil, but greatly reduced catalase and saccharase activities, and increased β-glucosidase activity on the seventh day after EDDS application. On the 28th day, no significant difference was observed in the enzyme activities (except for β-glucosidase) of EDDS-treated soils compared to the controls. Analysis of phospholipid fatty acids (PLFAs) showed that the application of 3 mmol kg(-1) EDDS did not cause significant stress to soil microbial communities. However, PCR-denaturing gradient gel electrophoresis (PCR-DGGE) fingerprint revealed that EDDS influenced the bacterial communities in the soils, and the effects on bean soils were more significant than that with corn. In general, the enzyme activities and bacterial communities were influenced by the application of EDDS, but the impact became weaker or even disappeared with the biodegradation of EDDS.