Fig 1.
Differences in microbial community composition in the whole soil using the Bray-Curtis dissimilarity index for β-diversity using NMDS.
Community composition (a) within the 2011 growing season for each topographic position (3 months x 3 plots x 2 cropping systems), (b) in July 2011 and 2012 for each topographic position (2 years x 3 plots x 2 cropping systems) and (c) between the annual (corn) and perennial (switchgrass) cropping systems (3 months x 3 plots x 3 topographic positions). Using PERMANOVAs, we detected only effects of topographic position for all comparisons. Ellipses represent a centroid of one standard deviation of points.
Table 1.
P-values for ANOVA for microbial richness, Shannon’s H’ and evenness and PERMANOVA for Bray-Curtis dissimilarity
Fig 2.
Changes in microbial richness, Shannon’s H’ and evenness at three topographic positions throughout the 2011 growing season on the summit, back slope and toe slope.
These variables were not affected by cropping system or sampling date so values represent means and 95% CI’s of combined annual and perennial treatments at each sampling time.
Fig 3.
Changes in α-diversity of the microbial communities in July in the whole soil and rhizosphere soil from annual (corn) and perennial (switchgrass) cropping systems at two topographic positions at the Landscape Biomass Project.
Means and 95% CI’s are shown.
Fig 4.
Differences in microbial community composition between whole soil and rhizosphere soil using the Bray-Curtis dissimilarity index for β-diversity (1 date x 3 plots x 2 cropping systems x 2 topographic positions).
We detected only effects of topographic position for all comparisons. Ellipses represent a centroid of one standard deviation of points.
Fig 5.
Change in rank abundance from whole to rhizosphere soil for Actinomycetales, Saprospirales, Syntrophobacterales, Nitrospirales, and MND1 bacterial orders.
Positive values indicate the order has a higher rank in the whole soil and negative values indicate the order has a higher rank in the rhizosphere soil. Error bars represent 95% CI’s.