Addition of microbes shifts the ability of soil carbon sequestration in the process of soil Cd remediation

Without accurate data on soil carbon (C) components and the relationships between soil C, soil respiration and biological C, it is challenging to produce assessments of the C sequestration rate in the process of soil remediation. Accordingly, it is essential to investigate the variations of soil C sources in different remediation treatments.

To find out the contributors of soil C sequestration, we compared the different forms of soil C and soil respiration in cadmium (Cd)-polluted soil with morning glory, microbes or morning glory + microbe (M + microbe) remediation treatments.

Results indicated that (1) M + microbe treatments showed a higher Cd removal rate than microbe treatments; (2) soil C contents in morning glory + Lactobacillus + Saccharomyces (M + I) treatment was highest on day 80, however, soil C contents and soil respiration in other treatments declined with increasing remediation time; (3) soils with microbe application had higher microbial biomass carbon (MBC) compared with soils without microbe application; (4) nematode production C and respiration C increased with remediation duration; (5) the connection between soil organic carbon (SOC) and MBC was not observable; and (6) the disparities in soil C components between day 40 and day 80 were more pronounced compared with those between day 80 and day 120.

The paper discusses the strengths and weaknesses of each soil Cd remediation methods, ultimately determining that the integration of morning glory, Bacillus velezensis and Saccharomyces may maximize the rate of soil carbon sequestration.