Impacts of Cropping Systems and Long-Term Tillage on Soil Microbial Population Levels and Community Composition in Dryland Agricultural Setting
Table 3
Correlations () of bacterial phyla abundances and other microbial parameters with characteristics of soils from long-term tillage and rotation treatments.a
Soil characteristicsc,d
HWE
EE-GRSP
T-GRSP
Phylogenetic groupb/microbial parameter
pH
OC
TN
MB-C
MB-N
MB-P
SC
DOC
TDN
NH3-N
EE-GRSP
NH3-N
T-GRSP
NH3-N
Acidobacteria
0.94−
0.85+
0.89+
0.78+
0.85+
0.78+
0.83+
0.98+
0.99+
0.99+
0.69+
0.85+
0.78+
0.88+
Actinobacteria
0.52+
0.14
0.18
0.07
0.13
0.15
0.15
0.34
0.35
0.39
0.04
0.16
0.16
0.17
Bacteroidetes
0.56+
0.95−
0.93−
0.99−
0.96−
0.87−
0.92−
0.81−
0.81−
0.77−
0.97−
0.92−
0.85−
0.94−
Cyanobacteria
0.27
0.00
0.00
0.01
0.00
0.01
0.00
0.04
0.06
0.08
0.05
0.00
0.01
0.00
Firmicutes
0.65+
0.64−
0.66−
0.70−
0.68−
0.47
0.56−
0.60−
0.64−
0.63−
0.59−
0.57−
0.43
0.65−
Gemmatimonadetes
0.25
0.49
0.47
0.61−
0.53−
0.36
0.42
0.33
0.34
0.32
0.56−
0.42
0.32
0.48
Planctomycetes
0.34
0.79+
0.76+
0.72+
0.75+
0.91+
0.85+
0.72+
0.67+
0.63+
0.79+
0.83+
0.93+
0.77+
Proteobacteria
0.06
0.26
0.24
0.18
0.22
0.41
0.32
0.26
0.22
0.21
0.24
0.32
0.45
0.24
α-Proteobacteria
0.30
0.26
0.27
0.16
0.23
0.35
0.31
0.40
0.37
0.38
0.16
0.31
0.39
0.27
β-Proteobacteria
0.89−
0.36
0.42
0.29
0.37
0.29
0.33
0.60+
0.63+
0.68+
0.19
0.35
0.29
0.40
γ-Proteobacteria
0.02
0.10
0.07
0.18
0.11
0.08
0.09
0.01
0.01
0.00
0.22
0.08
0.06
0.08
δ-Proteobacteria
0.31
0.14
0.17
0.07
0.12
0.20
0.17
0.30
0.29
0.32
0.06
0.18
0.23
0.16
Verrucomicrobia
0.05
0.06
0.04
0.04
0.04
0.16
0.10
0.02
0.01
0.00
0.11
0.09
0.18
0.04
Unclassified bacteria
0.61−
0.95+
0.94+
0.99+
0.97+
0.87+
0.92+
0.84+
0.83+
0.80+
0.96+
0.92+
0.84+
0.95+
qPCR Bacteria
0.45
0.09
0.12
0.03
0.08
0.09
0.09
0.27
0.28
0.31
0.01
0.10
0.11
0.11
qPCR Fungi
0.10
0.59+
0.53+
0.69+
0.59+
0.58+
0.58+
0.34
0.32
0.03
0.76+
0.57+
0.55+
0.55+
qPCR Bact : Fungal Ratio
0.03
0.04
0.02
0.10
0.05
0.02
0.03
0.00
0.00
0.00
0.12
0.02
0.01
0.03
Chao I Richness
0.51−
0.57+
0.59+
0.45
0.54+
0.67+
0.63+
0.70+
0.67+
0.67+
0.46
0.63+
0.71+
0.58+
Shannon’s Diversity
0.00
0.04
0.04
0.11
0.06
0.01
0.02
0.00
0.01
0.00
0.09
0.02
0.00
0.04
aCorrelations ≥ 0.50 are further described at positive (+) or negative (−) using superscript symbols following the correlation values.
bPhyla which were detected in less than three treatments (Table 2) were not analyzed.
cOC: organic carbon; TN: total nitrogen; MB: microbial biomass (C, N, and P); HWE: hot water extractable; SC: soil carbohydrates; DOC: dissolved organic carbon; TDN: total dissolved nitrogen; EE-GRSP and T-GRSP: easily extractable and total glomalin-related soil protein.
dOC and TN values were analyzed as a percentage of the soil fraction. All other values, except for pH, were analyzed as mg/kg soil.
