Lacking of systematic evaluations in soil quality and microbial
community recovery after different amendments addition limits
optimization of amendments combination in coal mine-soils. We performed
a short-term incubation experiment over 12 weeks to assess the effects
of three amendments (biochar: C; nitrogen fertilizer at three levels:
N-N1~N3; microbial agent at two levels:
M-M1~M2) based on C/N ratio (regulated by biochar and N
level: 35:1, 25:1, 12.5:1) on soil quality and microbial community in
the Qilian Mountains, China. Over the incubation period, soil pH and
MBC/MBN were significantly lower than unamended treatment in N addition
and C+M+N treatments, respectively. Soil organic carbon (SOC), total
nitrogen (TN), available nitrogen (AN), available phosphorus (AP),
available potassium (AK), microbial biomass carbon (MBC) and microbial
biomass nitrogen (MBN) contents had a significant increase in all
amended treatments (P<0.001). Higher AP, AK, MBC, MBN and
lower MBC/MBN were observed in N2-treated soil(corresponding to C/N
ratio of 25:1). Meanwhile, N2-treated soil significantly increased
species richness and diversity of soil bacterial community
(P<0.05). Principal coordinate analysis further showed that
soil bacterial community compositions were significantly separated by N
level. C-M-N treatments (especially at N2 and N1 levels) significantly
increased the relative abundance (>1%) of the bacterial
phyla Bacteroidetes and Firmicutes, and decreased the relative abundance
of fungal phyla Chytridiomycota (P<0.05). Redundancy analysis
illustrated the importance of soil nutrients in explaining variability
in bacteria community composition (74.73%) than fungal (35.0%). Our
results indicated that N and M addition based on biochar can improve
soil quality by neutralizing soil pH and increasing soil nutrient
contents, and the appropriate C/N ratio (25:1: biochar+N2-treated soil)
can better promote mass, richness and diversity of soil bacterial
community. Our study provided a new insight for achieving restoration of
damaged habitats by changing microbial structure, diversity and mass by
regulating C/N ratio of amendments
Efficiency of biochar, nitrogen addition, and microbial agent amendments in remediation of soil properties and microbial community in Qilian Mountains mine soils
