scholarly journals Impact of high carbon amendments and pre-crops on soil bacterial communities

2020 ◽  
Vol 57 (2) ◽  
pp. 305-317
Author(s):  
Catherine W. Kamau ◽  
Richard van Duijnen ◽  
Christoph A. O. Schmid ◽  
Helga E. Balàzs ◽  
Julien Roy ◽  
...  
Keyword(s):  
Wheat Straw ◽  
Bacterial Diversity ◽  
Bacterial Communities ◽  
Spring Barley ◽  
Winter Barley ◽  
Soil Microbiome ◽  
Molecular Barcoding ◽  
Soil Bacterial Communities ◽  
C Stocks ◽  
Soil Bacterial

AbstractA 2-year outdoor mesocosm experiment was carried out to determine the effects of high C amendments (HCAs; wheat straw and sawdust) compared to a control with no addition of HCAs (no-HCA) and 2 different crop rotation systems (spring barley/winter barley and faba bean/winter barley) on soil bacterial communities using a molecular barcoding approach. Samples were analyzed after pre-crop harvest (T1) and harvest of winter barley (T2). Our data demonstrate a clear drop in bacterial diversity after winter barley harvest in the no-HCA and wheat straw treatment compared to the pre-crops. Sawdust application had a stabilizing effect on bacterial diversity compared to the pre-crops and induced an increase in carbon (C) stocks in soil which were however negatively correlated with yields. Main responders in the no-HCA and wheat straw treatment compared to the pre-crops were bacteria of the phyla Actinobacteria and Bacteroidetes which were enriched and bacteria belonging to Firmicutes, Gemmatimonadetes, Proteobacteria, and Gemmatimonadaceae which were depleted. Overall differences between wheat straw–amended and no-HCA control samples were small and included single ASVs from various phyla. In sawdust-amended samples, only a shift of some Proteobacteria families was observed compared to the no-HCA control. Overall, pre-crop plant species had small influence on the observed response pattern of the soil microbiome towards the amendments and was only visible for wheat straw.

scholarly journals The role of ecosystem engineers in shaping the diversity and function of arid soil bacterial communities

2020 ◽  
Author(s):  
Capucine Baubin ◽  
Arielle M. Farrell ◽  
Adam Šťovíček ◽  
Lusine Ghazaryan ◽  
Itamar Giladi ◽  
...  
Keyword(s):  
Bacterial Communities ◽  
Soil Samples ◽  
Ecosystem Engineers ◽  
Soil Microbiome ◽  
Desert Ecosystems ◽  
Arid Soil ◽  
Soil Bacterial Communities ◽  
Ant Nests ◽  
Soil Bacterial ◽  
And Function

ABSTRACTEcosystem engineers (EEs) are present in every environment and are known to strongly influence ecological processes and thus shape the distribution of species and resources. In this study, we assessed the direct and indirect effect of two EEs (perennial shrubs and ant nests), individually and combined, on the composition and function of arid soil bacterial communities. To that end, top soil samples were collected in the Negev Desert Highlands during the dry season from four patch types: (1) barren soil; (2) under shrubs; (3) near ant nests; or (4) near ant nests situated under shrubs. The bacterial composition was evaluated in the soil samples (fourteen replicates per patch type) using 16S rRNA gene amplicon sequencing, together with physico-chemical measures of the soil, and the potential functions of the community. We have found that the EEs differently affected the community composition. Indeed, barren patches supported a soil microbiome, dominated by Rubrobacter and Proteobacteria, while in EE patches the Deinococcus-Thermus phylum was dominating. The presence of the EEs similarly enhanced the abundance of phototrophic, nitrogen cycle and stress- related genes. In addition, only when both EEs were combined, were the soil characteristics altered. Our results imply that arid landscapes foster unique communities selected by each EE(s), solo or in combination, yet these communities have similar potential biological traits to persist under the harsh arid conditions. Environments with multiple EEs are complicated to study due to the possibility of non-additive effects of EEs and thus further research should be done.IMPORTANCEEcosystem engineers are organisms that can create, modify, or maintain their habitat. They are present in various environments but are particularly conspicuous in desert ecosystems, where their presence is tightly linked to vital resources like water or nutrients. Despite their key role in structuring and controlling desert ecosystems, joint engineering, and their effect on soil function, are unknown. Our study explores the contributions of key ecosystem engineers to the diversity and function of their soil microbiome allowing better understanding of their role in shaping habitats and engineering their activity

scholarly journals Long-term nutrient enrichment of an oligotroph-dominated wetland increases bacterial diversity in bulk soils and plant rhizospheres

2020 ◽  
Author(s):  
Regina B. Bledsoe ◽  
Carol Goodwillie ◽  
Ariane L. Peralta
Keyword(s):  
Bacterial Community ◽  
Bacterial Diversity ◽  
Community Composition ◽  
Nutrient Enrichment ◽  
Bacterial Communities ◽  
Nutrient Addition ◽  
Soil Microbiome ◽  
The Core ◽  
Soil Bacterial

ABSTRACTIn nutrient-limited conditions, plants rely on rhizosphere microbial members to facilitate nutrient acquisition, and in return plants provide carbon resources to these root-associated microorganisms. However, atmospheric nutrient deposition can affect plant-microbe relationships by changing soil bacterial composition and by reducing cooperation between microbial taxa and plants. To examine how long-term nutrient addition shapes rhizosphere community composition, we compared traits associated with bacterial (fast growing copiotrophs, slow growing oligotrophs) and plant (C3 forb, C4 grass) communities residing in a nutrient poor wetland ecosystem. Results revealed that oligotrophic taxa dominated soil bacterial communities and that fertilization increased the presence of oligotrophs in bulk and rhizosphere communities. Additionally, bacterial species diversity was greatest in fertilized soils, particularly in bulk soils. Nutrient enrichment (fertilized vs. unfertilized) and plant association (bulk vs. rhizosphere) determined bacterial community composition; bacterial community structure associated with plant functional group (grass vs. forb) was similar within treatments but differed between fertilization treatments. The core forb microbiome consisted of 602 unique taxa, and the core grass microbiome consisted of 372 unique taxa. Forb rhizospheres were enriched in potentially disease suppressive bacterial taxa and grass rhizospheres were enriched in bacterial taxa associated with complex carbon decomposition. Results from this study demonstrate that fertilization serves as a strong environmental filter on the soil microbiome, which leads to distinct rhizosphere communities and can shift plant effects on the rhizosphere microbiome. These taxonomic shifts within plant rhizospheres could have implications for plant health and ecosystem functions associated with carbon and nitrogen cycling.ImportanceOver the last century, humans have substantially altered nitrogen and phosphorus cycling. Use of synthetic fertilizer and burning of fossil fuels and biomass have increased nitrogen and phosphorous deposition, which results in unintended fertilization of historically low-nutrient ecosystems. With increased nutrient availability, plant biodiversity is expected to decline and bacterial communities are anticipated to increase in abundance of copiotrophic taxa. Here, we address how bacterial communities associated with different plant functional types (forb, grass) shift due to long-term nutrient enrichment. Unlike other studies, results revealed an increase in bacterial diversity, particularly, of oligotrophic bacteria in fertilized plots. We observed that nutrient addition strongly determines forb and grass rhizosphere composition, which could indicate different metabolic preferences in the bacterial communities. This study highlights how long-term fertilization of oligotroph-dominated wetlands could alter the metabolism of rhizosphere bacterial communities in unexpected ways.

scholarly journals The effects of afforestation on soil bacterial communities in temperate grassland are modulated by soil chemical properties

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6147 ◽  
Author(s):  
Shu-Hong Wu ◽  
Bing-Hong Huang ◽  
Jian Gao ◽  
Siqi Wang ◽  
Pei-Chun Liao
Keyword(s):  
Bacterial Community ◽  
Bacterial Communities ◽  
Chemical Properties ◽  
Soil Chemical Properties ◽  
Soil Microbiome ◽  
Apparent Lack ◽  
Soil P ◽  
Soil Bacterial Communities ◽  
Abundant Otus ◽  
Soil Bacterial

Grassland afforestation dramatically affects the abiotic, biotic, and ecological function properties of the original ecosystems. Interference from afforestation might disrupt the stasis of soil physicochemical properties and the dynamic balance of microbiota. Some studies have suggested low sensitivity of soil properties and bacterial community to afforestation, but the apparent lack of a significant relationship is probably due to the confounding effects of the generalist habitat and rare bacterial communities. In this study, soil chemical and prokaryotic properties in a 30-year-old Mongolia pine (Pinus sylvestris var. mongolica Litv.) afforested region and adjacent grassland in Inner Mongolia were classified and quantified. Our results indicate that the high richness of rare microbes accounts for the alpha-diversity of the soil microbiome. Few OTUs of generalist (core bacteria) and habitat-specialist bacteria are present. However, the high abundance of this small number of OTUs governs the beta-diversity of the grassland and afforested land bacterial communities. Afforestation has changed the soil chemical properties, thus indirectly affecting the soil bacterial composition rather than richness. The contents of soil P, Ca2+, and Fe3+ account for differentially abundant OTUs such as Planctomycetes and subsequent changes in the ecologically functional potential of soil bacterial communities due to grassland afforestation. We conclude that grassland afforestation has changed the chemical properties and composition of the soil and ecological functions of the soil bacterial community and that these effects of afforestation on the microbiome have been modulated by changes in soil chemical properties.

scholarly journals Impact of Land Use on Bacterial Diversity and Community Structure in Temperate Pine and Indigenous Forest Soils

Diversity ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 217 ◽  
Author(s):  
Adenike Eunice Amoo ◽  
Olubukola Oluranti Babalola
Keyword(s):  
Land Use ◽  
Microbial Communities ◽  
Bacterial Diversity ◽  
Correspondence Analysis ◽  
Canonical Correspondence Analysis ◽  
Bacterial Communities ◽  
Soil Microbial Communities ◽  
Soil Characteristics ◽  
Soil Bacterial Communities ◽  
Soil Bacterial

Soil microbial communities are an important part of ecosystems that possess the capability to improve ecosystem services; however, several aspects of the ecology of forest soil bacterial communities are still unknown. Here, we investigated the impact of land-use change on soil bacterial communities and the soil characteristics. High-throughput sequencing was used to ascertain the bacterial diversity and canonical correspondence analysis was used to determine relationships between the bacterial communities and environmental variables. Our results show spatial heterogeneity in the distribution of the microbial communities and significant relationships between the microbes and soil characteristics (axis 1 of the canonical correspondence analysis (CCA) plot explained 64.55% of the total variance while axis 2 described 24.49%). Knowledge of this is essential as it has direct consequences for the functioning of the soil ecosystem.

scholarly journals Effects of Imazapyr on Spartina alterniflora and Soil Bacterial Communities in a Mangrove Wetland

Water ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3277
Author(s):  
Xue Mo ◽  
Panpan Dong ◽  
Lumeng Xie ◽  
Yujiao Xiu ◽  
Yanqi Wang ◽  
...  
Keyword(s):  
Bacterial Diversity ◽  
Spartina Alterniflora ◽  
Bacterial Communities ◽  
Available Phosphorus ◽  
Soil Bacterial Diversity ◽  
Factors Affecting ◽  
Soil Bacterial Communities ◽  
Mangrove Wetland ◽  
Significant Difference ◽  
Soil Bacterial

The invasion of Spartina alterniflora (S. alterniflora) has caused serious damage to coastal wetland ecosystems in China, especially the mangrove wetlands in South China. This study aimed to validate the effect of imazapyr on S. alterniflora and soil. The controlled experiment was conducted in May 2021 at the Zhangjiangkou Mangrove Wetland Reserve. In the experiment, 25% (W) imazapyr was used, and six treatments were set up: 3035, 6070, and 9105 mL/acre 25% imazapyr and 1299, 2604, and 5202 mL/acre of AGE 809 + 6070 mL/acre 25% imazapyr. The results showed no side effects on mangrove plants in the spraying area. The highest control efficiency (95.9%) was given by 2604 mL/acre of AGE 809 + 6070 mL/acre 25% imazapyr. The residues of imazapyr in different soils were reduced to 0.10–0.59 mg/kg. The sequencing results showed no significant difference in the overall bacterial communities under different treatments (p > 0.05). The soil bacterial diversity in the samples with adjuvant was higher than that in the samples without adjuvant, while the abundance values were the opposite. There were 10 main communities (>0.3%) at phylum level in all soil samples, among which Proteobacteria, Bacteroidetes, Acidobacteria, Chloflexi, and Actinobacteria were the dominant communities, and the latter four’s abundance changed significantly (p < 0.05). There were significant abundance differences between the groups of oligotrophic and eutrophic bacteria. The redundancy analysis and Monte Carlo tests showed that the total organic carbon (TOC), total phosphorus (TP), available phosphorus (AP), ammonia nitrogen, and total nitrogen were the main factors affecting soil bacterial diversity. At the same time, TOC, AP, and TP were the most critical factors affecting the overall characteristics of soil bacterial communities in different treatments, while soil residues had no significant effect on bacteria. This might be due to the addition and degradation of imazapyr and the coverage of S. alterniflora. The best recommendation is 2604 mL/acre of AGE 809 + 6070 mL/acre 25% imazapyr to be applied in China’s mangrove wetland reserves and coastal wetlands.

scholarly journals The Spatial Factor, Rather than Elevated CO2, Controls the Soil Bacterial Community in a Temperate Forest Ecosystem

2010 ◽  
Vol 76 (22) ◽  
pp. 7429-7436 ◽  
Author(s):  
Yuan Ge ◽  
Chengrong Chen ◽  
Zhihong Xu ◽  
Ram Oren ◽  
Ji-Zheng He
Keyword(s):  
Bacterial Community ◽  
Bacterial Diversity ◽  
Bacterial Communities ◽  
Temperate Forest ◽  
Soil N ◽  
Soil Bacterial Communities ◽  
Spatial Factor ◽  
Soil Bacterial ◽  
Diversity Estimates ◽  
Total Soil N

ABSTRACT The global atmospheric carbon dioxide (CO2) concentration is expected to increase continuously over the next century. However, little is known about the responses of soil bacterial communities to elevated CO2 in terrestrial ecosystems. This study aimed to partition the relative influences of CO2, nitrogen (N), and the spatial factor (different sampling plots) on soil bacterial communities at the free-air CO2 enrichment research site in Duke Forest, North Carolina, by two independent techniques: an entirely sequencing-based approach and denaturing gradient gel electrophoresis. Multivariate regression tree analysis demonstrated that the spatial factor could explain more than 70% of the variation in soil bacterial diversity and 20% of the variation in community structure, while CO2 or N treatment explains less than 3% of the variation. For the effects of soil environmental heterogeneity, the diversity estimates were distinguished mainly by the total soil N and C/N ratio. Bacterial diversity estimates were positively correlated with total soil N and negatively correlated with C/N ratio. There was no correlation between the overall bacterial community structures and the soil properties investigated. This study contributes to the information about the effects of elevated CO2 and soil fertility on soil bacterial communities and the environmental factors shaping the distribution patterns of bacterial community diversity and structure in temperate forest soils.

scholarly journals Exploring Soil Bacterial Communities in Different Peanut-Cropping Sequences Using Multiple Molecular Approaches

2011 ◽  
Vol 101 (7) ◽  
pp. 819-827 ◽  
Author(s):  
Hari Sudini ◽  
Mark R. Liles ◽  
Covadonga R. Arias ◽  
Kira L. Bowen ◽  
Robin N. Huettel
Keyword(s):  
Community Structure ◽  
Bacterial Diversity ◽  
Bacterial Communities ◽  
Plant Pathogens ◽  
Soil Sampling ◽  
Soil Microbial Community Structure ◽  
Soil Bacterial Communities ◽  
Soilborne Plant Pathogens ◽  
Soil Bacterial ◽  
Crop Health

Soil bacterial communities have significant influence on soilborne plant pathogens and, thus, crop health. The present study focuses on ribotyping soil bacterial communities in different peanut-cropping sequences in Alabama. The objective was to identify changes in microbial assemblages in response to cropping sequences that can play a role in managing soilborne plant pathogens in peanut. Four peanut-cropping sequences were sampled at the Wiregrass Research Station, Headland, AL in 2006 and 2007, including continuous peanut, 4 years of bahiagrass followed by peanut, peanut-cotton, and peanut-corn-cotton. Soil sampling was done at early and mid-season and at harvest. Bacterial community structure was assessed using ribosomal intergenic spacer analysis (RISA) combined with 16S rRNA cloning and sequencing. RISA results indicated >70% dissimilarities among different cropping sequences. However, 90% similarities were noticed among replicated plots of the same cropping sequences. Cropping sequences and time of soil sampling had considerable effect on soil microbial community structure. Bahiagrass rotation with peanut was found to have the highest bacterial diversity, as indicated by a high Shannon Weaver Diversity index. Overall, higher bacterial diversity was observed with bahiagrass and corn rotations compared with continuous peanut. The bacterial divisions Proteobacteria, Acidobacteria, Firmicutes, Bacteroidetes, and Actinomycetes were the predominant bacterial phyla found in all peanut-cropping sequences. The Proteobacteria taxa in these soils were negatively correlated with the abundance of members of division Firmicutes but, conversely, had a significant positive correlation with Gemmatimonadetes taxa. The prevalence of the division Actinomycetes was negatively correlated with the relative abundance of members of division Verrucomicrobia. These results indicate complex interactions among soil bacteria that are important contributors to crop health.

scholarly journals Pavement Overrides the Effects of Tree Species on Soil Bacterial Communities

2021 ◽  
Vol 18 (4) ◽  
pp. 2168
Author(s):  
Yinhong Hu ◽  
Weiwei Yu ◽  
Bowen Cui ◽  
Yuanyuan Chen ◽  
Hua Zheng ◽  
...  
Keyword(s):  
Bacterial Community ◽  
Bacterial Diversity ◽  
Community Composition ◽  
Tree Species ◽  
Bacterial Communities ◽  
Bacterial Community Composition ◽  
Soil Bacterial Community ◽  
Soil Bacterial Communities ◽  
Pine Stands ◽  
Soil Bacterial

Human disturbance and vegetation are known to affect soil microorganisms. However, the interacting effects of pavement and plant species on soil bacterial communities have received far less attention. In this study, we collected soil samples from pine (Pinus tabuliformis Carr.), ash (Fraxinus chinensis), and maple (Acer truncatum Bunge) stands that grew in impervious, pervious, and no pavement blocks to investigate the way pavement, tree species, and their interaction influence soil bacterial communities by modifying soil physicochemical properties. Soil bacterial community composition and diversity were evaluated by bacterial 16S amplicon sequencing. The results demonstrated that soil bacterial community composition and diversity did differ significantly across pavements, but not with tree species. The difference in soil bacterial community composition across pavements was greater in pine stands than ash and maple stands. Soil bacterial diversity and richness indices decreased beneath impervious pavement in pine stands, and only bacterial richness indices decreased markedly in ash stands, but neither showed a significant difference across pavements in maple stands. In addition, bacterial diversity did not differ dramatically between pervious pavement and no pavement soil. Taken together, these results suggest that pavement overwhelmed the effects of tree species on soil bacterial communities, and had a greater effect on soil bacterial communities in pine stands, followed by ash and maple stands. This study highlights the importance of anthropogenic disturbance, such as pavement, which affects soil microbial communities.

Differences in the Soil Bacterial Communities Under Organic Farming and Conventional Farming Modes Revealed by 16S rDNA Sequencing

2021 ◽  
Vol 15 (1) ◽  
pp. 10-19
Author(s):  
Yazhen Yang ◽  
Mingke Fang ◽  
Meiyan Wu ◽  
Huaisheng Zhang ◽  
Huizhen Li ◽  
...  
Keyword(s):  
Soil Sample ◽  
Bacterial Diversity ◽  
Organic Farming ◽  
Bacterial Communities ◽  
Mode Analysis ◽  
Strong Positive Correlation ◽  
Conventional Farming ◽  
Available Nitrogen ◽  
Soil Bacterial Communities ◽  
Soil Bacterial

Soil bacterial communities are different in various agricultural ecosystems. To assess the differences in soil bacterial communities between organic and conventional farming modes, high-throughput Illumina MiSeq sequencing was conducted. A total of 3, 919 operational taxonomic units were identified and classified as 26 phyla, 42 classes, 78 orders, 120 families, 281 genera, and 340 known species. The histogram of the microbial species distribution at genera levels showed that Massiliaand Lysobacter increased quickly in soil under organic farming mode. Analysis of soil bacterial diversity showed that the soil under the organic farming had a greater bacterial diversity. Linear discriminant analysis effect size analysis showed that the major bacterial groups identified in the soil sample CK1 (2015.4) and CK6 (2017.10) under conventional farming mode were largely different from those in the soil sample 06 (2017.10) under organic farming mode. Redundancy analysis demonstrated that available nitrogen was the most important factor regulating bacterial composition under the organic farming mode. Massilia, Pseudomonas, Lysobacter and Pseudarthrobacterabundances showed a strong positive correlation with the content of available nitrogen. The results provided an important reference for the utilization of soil microorganisms under the organic farming mode.

scholarly journals Ammonium and Nitrate Shift the Spatial Distribution of Soil Bacterial Communities and Association Networks Along a Distance from Maize Roots in an Acidic Red Soil

2020 ◽  
Author(s):  
Hao Qing Zhang ◽  
Xue Qiang Zhao ◽  
Yu Shi ◽  
Yuting Liang ◽  
Ren Fang Shen
Keyword(s):  
Spatial Distribution ◽  
Community Structure ◽  
Bacterial Community ◽  
Bacterial Diversity ◽  
Soil Ph ◽  
Bacterial Communities ◽  
Root Zone ◽  
Soil Bacterial Communities ◽  
Maize Roots ◽  
Soil Bacterial

Abstract Background: Ammonium (NH4+) and nitrate (NO3−) are two major inorganic nitrogen (N) forms available for plant growth. Soil microbes affect the availability and transformation of these N forms in the rhizosphere, and this affects the N-use efficiency of plants. However, little is known about the responses of the rhizosphere bacterial community structure to NH4+ and NO3−. Here, a rhizobox containing a root zone (root growing area) and various soil compartments (0–0.5 cm, 0.5–1 cm, 1–2 cm, 2–4 cm, and 4–9 cm from the root zone) was designed to investigate the spatial distribution of bacterial diversity, community structure, and co-occurrence patterns along a distance from maize (Zea mays L.) roots with the addition of 15N-labeled NH4+ or NO3− in an acidic red soil.Results: Addition of NH4+ and NO3− reduced soil bacterial diversity in the maize root zone. The structures of soil bacterial communities differed between NH4+ and NO3− in the root zone and 0.5 cm away from the root zone. Soil pH was the major driver of bacterial community assembly during plant uptake of N. Maize roots recruited potentially beneficial acidophilic bacteria (e.g. Acidibacter, Burkholderia, and Catenulispora) under NH4+ treatment, and recruited growth-promoting bacteria that prefer higher pH (e.g. Sphingomonas, Sphingobium, Azospirillum, and Novosphingobium) under NO3− treatment. In the N-fertilization treatments, the soil bacterial networks were more complex in the root zone and its adjacent 0.5–1 cm zone than in other soil compartments. The soil bacterial networks were more complex under NH4+ treatment than under NO3−. More bacterial taxa in the networks responded positively and negatively to soil residual NH4+ than to NO3− in all zones in the rhizobox.Conclusions: The combined effects of the N form and the rhizosphere influenced the spatial patterns and co-occurrence network of soil bacterial communities at different distances from the maize root zone, mainly because of changes in soil pH during the uptake of NH4+ and NO3− by maize roots. Regulating microbial communities by adjusting soil pH through NH4+ and NO3− supply may be an environmentally friendly option for promoting soil microbial functions in intensively managed agro-ecosystems.

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