Restoration of Degraded Soil in the Nanmangalam Reserve Forest with Native Tree Species: Effect of Indigenous Plant Growth-Promoting Bacteria

Table 3

PCA analysis of soil microbial parameters under the rhizosphere of different tree species.

Parameters	Components
Variables	1	2	3	4
Variation (%)
Eigen value
Cumulative variations
pH
EC
SOC
TN
MBC
MBN
Soil basal respiration
Urease
Phosphatase
-glucosidase
Phenol oxidase
Dehydrogenase
Catalase
MBC/MBN
MBC/SOC
BSR/MBC

EC: electrical conductivity; SOC: soil organic carbon; TN: total nitrogen, MBC: microbial biomass carbon; MBN: microbial biomass nitrogen.
Extraction method: principal component analysis.
Four components extracted.
RSMI = 0.47 EC + 0.47 urease + 0.47 dehydrogenase + 0.47BSR/MBC + 0.21BSR + 0.21MBC/MBN + 0.21MBC/SOC.
Normalized RSMI = RSMI/2.51.
Final RSMI = 0.176EC + 0.169 urease + 0.153 dehydrogenase + 0.138 BSR:MBC + 0.0717BSR + 0.079MBC:MBN + 0.067MBC:SOC.