The NPK+S significantly increased SOC and available potassium (K)
and significantly enhanced N-acetyl-glucosamidase, β-xylosidase, urease, and phenol oxidase
activities. The NPK+G significantly improved total nitrogen (N), ammonium N, available
P, and N-acetyl-glucosamidase activity. The PLFA biomass was highest under NPK
+S, followed by NPK+M and NPK+G treatments. Principal component analysis (PCA) of the
PLFA indicated that soils with NPK+M and NPK+S contained higher proportions of unsaturated
and cyclopropane fatty acids (biomarkers of fungi and gram-negative bacteria) and
soil under NPK+G contained more straight chain saturated fatty acids (representing grampositive
bacteria). PCA of the DGGE patterns showed that organic amendments had a
greater influence on fungal community. Cluster analysis of fungal DGGE patterns revealed
that NPK+G was clearly separated. Meanwhile, the bacterial community of NPK+M treatment
was the most distinct. RDA analysis revealed changes of microbial community composition
mostly depended on β-xylosidase, β-cellobiosidase activities, total N and available K
contents. The abundances of gram-negative bacterial and fungal PLFAs probably effective
in improving fertility of low-yield albic paddy soil because of their significant influence on
DGGE profile.