Impact of Olive Saplings and Organic Amendments on Soil Microbial Communities and Effects of Mineral Fertilization

Abstract

Plant communities and fertilization may have an impact on soil microbiome. Most commercial olive trees are minerally fertilized, while this practice is being replaced by the use of organic amendments. Organic amendments can both fertilize and promote plant growth-promoting organisms. Our aims were (i) to describe the changes in soil bacterial and fungal communities induced by the presence of young olive trees and their interaction with organic amendments and (ii) to compare the effects of mineral and organic fertilization. We set up two parallel experiments in pots using a previously homogenized soil collected from a commercial olive orchard: in the first one, we grew olive saplings in unamended and organically amended soils with two distinct composts and compared these two soils incubated without a plant, while in the second experiment, we comparatively tested the effects of organic and mineral fertilization. OTUs and the relative abundances of bacterial and fungal genera and phyla were analyzed by 16S rRNA and ITS1 gene amplicon using high-throughput sequencing. Basal respiration and substrate-induced respiration were measured by MicroRespTM. The effects of the different treatments were analyzed in all phyla and in the 100 most abundant genera. The presence of olive saplings increased substrate-induced respiration and bacterial and fungal richness and diversity. Organic amendments greatly affected both bacterial and fungal phyla and increased bacterial richness while not affecting fungal richness. Mineral fertilization increased the relative abundance of the less metabolically active bacterial phyla (Actinobacteria and Firmicutes), while it reduced the most metabolically active phylum, Bacteroidetes. Mineral fertilization increased the relative abundance of three N2-fixing Actinobacteria genera, while organic fertilization only increased one genus of Proteobacteria. In organically and minerally fertilized soils, high basal respiration rates were associated with low fungal diversity. Basidiomycota and Chytridiomycota relative abundances positively correlated with basal respiration and substrate-induced respiration, while Ascomycota correlated negatively. Indeed, the Ascomycota phyla comprised most of the fungal genera decreased by organic amendments. The symbiotrophic phylum Glomeromycota did not correlate with any of the C sources. The relative abundance of this phylum was promoted by the presence of plants but decreased when amending soils with composts.

Responses of soil fungal communities and functional guilds to ~160 years of natural revegetation in the Loess Plateau of China

“…In current study, the sum of relative abundances of Ascomycota and Basidiomycota reached 72.39 to 95.90% across all revegetation stages (Table 2). This result aligned with earlier studies, which revealed that Ascomycota and Basidiomycota are the most ubiquitously dominant phyla in soil fungal communities (Bello et al, 2021;Llimós et al, 2021;Nuñez et al, 2021). There was an obvious transition at the phylum level which showing that the relative abundance of Basidiomycota steadily increased, while the relative abundance of Ascomycota gradually decreased along with natural revegetation (Table 2).…”

“…For instance, Ascomycota prefer high-quality and simple substrates (e.g., low C:N; Thomson et al, 2015), and flourish in oligotrophic environments (Yang et al, 2019). Whereas, Basidiomycota are inclined to degrade low-quality and recalcitrant substrates (e.g., high C:N; Thomson et al, 2015;Llimós et al, 2021), and thrive in copiotrophic environments (Yang et al, 2019).…”

Application of Manure Rather Than Plant-Origin Organic Fertilizers Alters the Fungal Community in Continuous Cropping Tobacco Soil

“…For instance, compared to plant-derived organic fertilizers, manure-derived organic fertilizers are abundant in N and P nutrients and contain more living microorganisms ( Xia et al, 2021 ). As a result, the response of the soil fungal community to organic fertilizers varied with the fertilizer type ( Ding et al, 2017 ; Llimos et al, 2021 ). The differences reflect in the diversity and species composition of the community as well as the tropic models ( Wang et al, 2018 ).…”

When chicken manure compost meets iron nanoparticles: an implication for the remediation of chlorophenothane-polluted riverine sediment

“…37,38 Microvirga is a symbiotic nitrogen-fixing bacterium, and its abundance usually increased only in the presence of plants and decreased after the addition of compost. 39 The use of nZVI mainly increased abundance of Lysobacter (5.3%) and Ramlibacter (2.7%), but decreased the abundance of Microvirga (1.2%). Lysobacter and Ramlibacter both belong to the bacterial phylum Proteobacteria (Table S2 †), and the abundance increase of these two bacterial genera might be related to the nZVI treatment and iron oxidation.…”