Fungal community shifts in soils with varied cover crop treatments and edaphic properties - PubMed (original) (raw)

Fungal community shifts in soils with varied cover crop treatments and edaphic properties

Mara L Cloutier et al. Sci Rep. 2020.

Abstract

Cover cropping is proposed to enhance soil microbial diversity and activity, with cover crop type affecting microbial groups in different ways. We compared fungal community compositions of bulk soils differing by cover crop treatment, season, and edaphic properties in the third year of an organic, conventionally tilled rotation of corn-soybean-wheat planted with winter cover crops. We used Illumina amplicon sequencing fungal assemblages to evaluate effects of nine treatments, each replicated four times, consisting of six single winter cover crop species, a three-species mixture, a six-species mixture, and fallow. Alpha-diversity of fungal communities was not affected by cover crop species identity, function, or diversity. Sampling season influenced community composition as well as genus-level abundances of arbuscular mycorrhizal (AM) fungi. Cover crop mixtures, specifically the three-species mixture, had distinct AM fungal community compositions, while cereal rye and forage radish monocultures had unique Core OTU compositions. Soil texture, pH, permanganate oxidizable carbon, and chemical properties including Cu, and P were important variables in models of fungal OTU distributions across groupings. These results showed how fungal composition and potential functions were shaped by cover crop treatment as well as soil heterogeneity.

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Conflict of interest statement

The authors declare no competing interests.

Figures

Figure 1

Figure 1

Relative abundances of genera across CC Function. Genera classified as AM fungi (ad) or as an Insect Pathogen (e). Lower case letters denote significant differences among Functions (p < 0.05; n = 8 for Fallow, n = 16 for Brassica, Grass, Legume, and Mixture). Circles represent outliers, the horizontal lines represent the median values, and the vertical lines represent the minimum and maximum values excluding outliers.

Figure 2

Figure 2

Relative abundances of genera across CC. Both genera, Acaulospora (a) and Funneliformis (b) were assigned to the AM fungal group. Lower case letters denote significant differences among CC (p < 0.05; n = 8). Circles represent outliers, the horizontal lines represent the median values, and the vertical lines represent the minimum and maximum values excluding outliers.

Figure 3

Figure 3

Relative abundances of genera in the AM fungal group by Season. Lower case letters denote significant differences between Time (p < 0.05; n = 36). Circles represent outliers, the horizontal lines represent the median values, and the vertical lines represent the minimum and maximum values excluding outliers.

Figure 4

Figure 4

Relational diagram showing differences in fungal community compositions across CC. Lines connecting CC’s indicate differences (p-value <0.05) calculated by pairwise PERMANOVA comparisons using the Bray-Curtis dissimilarity matrix (n = 4) and the RVAideMemoire package in R.

Figure 5

Figure 5

Constrained ordination plots using CCA models of OTU groupings. Important environmental variables selected using forward and backwards selection. (Supplementary Table 6). Each model that significantly explained the species dispersion across the OTU groupings are denoted with an *. Lengths of each vector indicate the correlation between the variable and the ordination. Percentages next to CCA1/CCA2 represent the amount of inertia explained by the axes, while total constrained var represents the amount of inertia accounted for by the vectors (environmental variables).

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