Combining mercapto-functionalized palygorskite with zinc affect cadmium
phytoavailability and soil microbial activity in rhizosphere soil
Abstract
Cadmium (Cd) pollution in soil pose a grave threat to human health.
Combining various approaches to reduce Cd accumulation in crops is an
active area of research to remediate farmlands with medium-high levels
of Cd contamination. The Mercapto-functionalized palygorskite (PGS-SH)
and zinc (Zn) application alone or in combination was investigated to
explore reduction of Cd uptake in B. chinensis L and transformation of
Cd in soil. The sole application of Zn or PGS-SH increased the biomass
of B. chinensis L. and decreased the concentration of Cd in plants, but
more improvements were observed from the combined application of Zn and
PGS-SH. Low concentration of exogenous Zn (50 mg/kg) significantly
increased the soil respiration rate (SRR) and the soil dehydrogenase
activity (sDHA), while promoted B. chinensis L. growth while inhibiting
Cd uptake. However, excessive exogenous Zn (≥ 200 mg/kg) significantly
inhibited B. chinensis L. growth and soil microbial activity. The
combined application of PGS-SH and Zn had the highest sDHA (145.59%)
and lowest transport factor (TF) (27.59%) compared with the CK. The
combination of PGS-SH and Zn fertilizer is a safe and effective means
for remediating Cd-contaminated soil and restoring microbial activity.