Table 1.
Description of the agricultural management and crop yield, averaged over the five years before the first sampling date, in June 2009 (2005–2009).
Table 2.
Soil characteristics according to site and agricultural management at the first sampling date, in June 2009.
Figure 1.
Ordination diagram from the Correspondence Analysis of the relative abundances for taxa defined at 0.05 distance.
The 2-D CA diagram account for 29% of inertia. Locations of soils are indicated by squares (Bengolea, B), circles (Monte Buey, MB), diamond (Pergamino, P) and triangles (Viale, V). Colors indicate soil management type: Poor no-till Agricultural Practices in red, Good no-till Agricultural Practices in blue and Natural Environment in green. Standard error ellipses show 95% confidence areas.
Figure 2.
Venn diagram of the overlap of OTUs from the different soil management practices at four geographical locations.
The numbers of overlapping tag sequences are indicated in the graph. Management practices are indicated at the bottom of each diagram: GAP: Good no-till Agricultural Practices, PAP: Poor no-till Agricultural Practices; NE: Natural Environment. Location labels are indicated with B (Bengolea), MB (Monte Buey), P (Pergamino) and V (Viale).
Table 3.
Results of indicator species analysis.
Figure 3.
Ordination diagram from Canonical Correspondence Analysis of bacterial taxa identified as indicators using IndVal.
Only OTUs identified with IndVal values higher than 0.75 were used in this analysis (Table S6). The 2-D ordination diagram CCA accounts for 66% of inertia. Samples are indicated by circles and site labels. OTUs are indicated by crosses, names are omitted. Arrows for quantitative variables show the direction of increase of each variable, and the length of the arrow indicates the degree of correlation with the ordination axes. Colors indicate soil management type: Poor no-till Agricultural Practices in red, Good no-till Agricultural Practices in blue; Natural Environment in green. Location labels are indicated with: B (Bengolea), MB (Monte Buey), P (Pergamino) and V (Viale).
Figure 4.
Quantitative phylogenetic group abundance of the OTUs targeted with a set of primers specific for Acidobacteria GP1A (panel A) and Rubellimicrobium genus (panel B).
Each soil sample subjected to the indicated management in the four geographical locations was sampled at the date showed in the boxes. Bars correspond to the average qPCR data of three independent samples. Colors indicate soil management type: Poor no-till Agricultural Practices in red, Good no-till Agricultural Practices in blue, and Natural Environment in green. Error bars are standard error.
Figure 5.
Indicator values for samples of soils under different agricultural management.
The geographic sites are indicated in the box. In each site bars are ordered from left to right to the successive sampling dates: June 2009, February 2010, September 2010 and February 2011. PAP, Poor no-till Agricultural Practices (red) and GAP, Good no-till Agricultural Practices (blue). Shadow areas are 95% confidence intervals of indicator of GAP (0.24, 0.71) and PAP (−1.31, −0.41). Error bars are standard error.