Effect of sludge amendment on soil organic carbon and glomalin related
soil protein in reconstructed mine substrates during 9-year reclamation
Abstract
A plant-complex substrate-microbe ecological restoration system was
constructed in field and sludge was added to the reconstructed mine
soils 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. A similar trend was also observed for GRSP. Besides, the
stable indexes of soil aggregates had been increasing until the seventh
year. In short, the tested variables in reconstructed mine soils after
3-7 years were insignificantly different from them in the treatment
without sludge amendment after 9 years (CK2). 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. Consequently, the plant-complex
substrate-microbe ecological restoration system can be used as an
effective technique in early mining soil reclamation.