Effect of sludge amendment on soil organic carbon and glomalin related
soil protein in reconstructed mine substrates during 9-year reclamation
Abstract
A field experiment was performed in reconstructed mine substrates (RMS)
constituted with coal gangue and fly ash, and sludge was added to the
RMS in order to speed up the reclamation process. The effect of sludge
addition on plant growth, microbial activity, soil aggregate stability
and aggregation-associated soil characteristics in 9-year
chronosequences was monitored. The results showed that the height and
the total biomass of ryegrass with sludge amendment increased with the
reclamation time and eventually reached 1.5 times and 4.3 times
respectively higher than the control (CK1) after 9 years. The sludge
amendment enhanced the content of aggregate binding agents such as SOC
and glomalin and the soil aggregate stability. The SOC, LFOC and HFOC in
RMS were increased by 151.35%, 247.41% and 132.82% over the CK1,
respectively. Besides, the tested variables in RMS after 3-7 years were
insignificantly different from them in the treatment without sludge
amendment after 9 years. A similar trend was also observed for GRSP.
Furthermore, a significant positive correlation between GRSP and SOC was
investigated in RMS, as well as GRSP and soil structure-related
variables. Biological stimulation of SOC and GRSP to soil accelerated
the recovery of soil structure and ecosystem function. As a result, the
sludge amendment can be used as an effective technique in soil
restoration.