Agriculture Reference
In-Depth Information
site 1 (Figure S4). For bacteria including all bacterial subgroups analyzed,
Box-Whisker plots revealed that the variability of the bacterial community
compositions among replicates was generally lower for alfalfa soils than
the scrubland soil, except for
Betaproteobacteria
at site 2 (Figure 1). The
lowest variability was found for alfalfa soils from site 1 (Figure 1). In
conclusion, a signifi cant and taxonomic group-dependent effect of land
use was observed for all four targeted phylogenetic groups. Variation in
community composition for soils under arable farmland use generally was
lower than that from scrubland sites.
TABLE 2:
Percent dissimilarity of microbial DGGE fingerprints of different taxa for soils
compared between alfalfa and scrubland or between site 1 and site 2.
Bacteria
Alpha-proteobacteria
Beta-proteobacteria
Actinobacteria
Land use
Site 1
25*
20.3*
68.6*
2.7*
Site 2
13.8*
25*
31.3*
3.7*
Site
Alfalfa
10.3*
11.8*
61.5*
3.7*
Scrubland
3.8
4.9
5.8
2.8*
*Significant (P < 0.05) difference in community fingerprints between treatments as
revealed by permutation tests.
5.3.2 TAXA RESPONSIVE TO LAND USE DETERMINED BY
PHYLOCHIP ANALYSIS
PhyloChip hybridizations were used to detect bacterial taxa with signifi-
cant responses to land use. A total of 2,243 OTUs belonging to 44 phyla
was detected (Table S2). The bacterial richness in terms of the number of
detected OTUs was significantly (p = 0.05) higher for the arable field soils
than for the scrubland soils.
OTUs responding to land use were identifi ed by multiple two-way ANO-
VA and only taxa with a high proportion (>18% which is much higher than the
unadjusted p-value) of discriminative OTUs were summarized in Table 3.
