scholarly journals Elevated Carbon Dioxide Alters the Structure of Soil Microbial Communities

2012 ◽  
Vol 78 (8) ◽  
pp. 2991-2995 ◽  
Author(s):  
Ye Deng ◽  
Zhili He ◽  
Meiying Xu ◽  
Yujia Qin ◽  
Joy D. Van Nostrand ◽  
...  

ABSTRACTPyrosequencing analysis of 16S rRNA genes was used to examine impacts of elevated CO2(eCO2) on soil microbial communities from 12 replicates each from ambient CO2(aCO2) and eCO2settings. The results suggest that the soil microbial community composition and structure significantly altered under conditions of eCO2, which was closely associated with soil and plant properties.

Author(s):  
Gabriela Fernandez-Gnecco ◽  
Kornelia Smalla ◽  
Lorrie Maccario ◽  
Søren J Sørensen ◽  
Pablo Barbieri ◽  
...  

Abstract Soil microbial communities are key players of ecosystem processes and important for crop and soil health. The Humid Pampas region in Argentina concentrates 75% of the national soybean production, which is based on intensive use of agrochemicals, monocropping and no-till. A long-term field experiment under no-till management in the southeast of the Argentinean Pampas provides a unique opportunity to compare soybean under monocropping with cultivation including alternating cover crops or in a three-phase rotation. We hypothesized that cropping regimes and season affect soil microbial community composition and diversity. Amplicon sequencing of 16S rRNA genes and internal transcribed spacer fragments showed a stronger microbial seasonal dynamic in conservation regimes compared to monocropping. In addition, several bacterial (e.g. Catenulispora, Streptomyces and Bacillus) and fungal genera (e.g. Exophiala) with cropping regime-dependent differential relative abundances were identified. Despite a temporal shift in microbial and chemical parameters, this study shows that long-term cropping regimes shaped the soil microbiota. This might have important implications for soil quality and soybean performance and should therefore be considered in the development of sustainable agricultural managements.


HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1128C-1128
Author(s):  
Shengrui Yao ◽  
Ian A. Merwin ◽  
Janice E. Thies

Apple (Malu ×domestica) replant disease (ARD) is a soil-borne disease syndrome of complex etiology that occurs worldwide when establishing new orchards in old fruit-growing sites. Methyl bromide (MB) has been an effective soil fumigant to control ARD, but safer alternatives to MB are needed. We evaluated soil microbial communities, tree growth, and fruit yield for three pre-plant soil treatments (compost amendment, soil treatment with a broad-spectrum fumigant, and untreated controls), and five clonal rootstocks (M7, M26, CG6210, CG30, and G16), in an apple replant site at Ithaca, N.Y. Molecular fingerprinting (PCR-DGGE) techniques were used to study soil microbial community composition of root-zone soil of the different soil treatments and rootstocks. Tree caliper, shoot growth, and yield were measured annually from 2002–04. Among the five rootstocks we compared, trees on CG6210 had the most growth and yield, while trees on M26 had the least growth and yield. Soil treatments altered soil microbial communities during the year after pre-plant treatments, and each treatment was associated with distinct microbial groups in hierarchical cluster analyses. However, those differences among fungal and bacterial communities diminished during the second year after planting, and soil fungal communities equilibrated faster than bacterial communities. Pre-plant soil treatments altered bulk-soil microbial community composition, but those shifts in soil microbial communities had no obvious correlation with tree performance. Rootstock genotypes were the dominant factor in tree performance after 3 years of observations, and different rootstocks were associated with characteristic bacterial, pseudomonad, fungal, and oomycetes communities in root-zone soil.


2018 ◽  
Vol 114 (5/6) ◽  
Author(s):  
Gilbert Kamgan Nkuekam ◽  
Don A. Cowan ◽  
Angel Valverde

Many studies, mostly in temperate regions of the northern hemisphere, have demonstrated that agricultural practices affect the composition and diversity of soil microbial communities. However, very little is known about the impact of agriculture on the microbial communities in other regions of the world, most particularly on the African continent. In this study, we used MiSeq amplicon sequencing of bacterial 16S rRNA genes and fungal ITS regions to characterise microbial communities in agricultural and natural grassland soils located in the Mpumalanga Province of South Africa. Nine soil chemical parameters were also measured to evaluate the effects of edaphic factors on microbial community diversity. Bacterial and fungal communities were significantly richer and more diverse in natural grassland than in agricultural soils. Microbial taxonomic composition was also significantly different between the two habitat types. The phylum Acidobacteria was significantly more abundant in natural grassland than in agricultural soils, while Actinobacteria and the family Nectriaceae showed the opposite pattern. Soil pH and phosphorus significantly influenced bacterial communities, whereas phosphorus and calcium influenced fungal communities. These findings may be interpreted as a negative impact of land-use change on soil microbial diversity and composition.


1999 ◽  
Vol 65 (3) ◽  
pp. 982-988 ◽  
Author(s):  
Saïd el Fantroussi ◽  
Laurent Verschuere ◽  
Willy Verstraete ◽  
Eva M. Top

ABSTRACT The effect of three phenyl urea herbicides (diuron, linuron, and chlorotoluron) on soil microbial communities was studied by using soil samples with a 10-year history of treatment. Denaturing gradient gel electrophoresis (DGGE) was used for the analysis of 16S rRNA genes (16S rDNA). The degree of similarity between the 16S rDNA profiles of the communities was quantified by numerically analysing the DGGE band patterns. Similarity dendrograms showed that the microbial community structures of the herbicide-treated and nontreated soils were significantly different. Moreover, the bacterial diversity seemed to decrease in soils treated with urea herbicides, and sequence determination of several DGGE fragments showed that the most affected species in the soils treated with diuron and linuron belonged to an uncultivated bacterial group. As well as the 16S rDNA fingerprints, the substrate utilization patterns of the microbial communities were compared. Principal-component analysis performed on BIOLOG data showed that the functional abilities of the soil microbial communities were altered by the application of the herbicides. In addition, enrichment cultures of the different soils in medium with the urea herbicides as the sole carbon and nitrogen source showed that there was no difference between treated and nontreated soil in the rate of transformation of diuron and chlorotoluron but that there was a strong difference in the case of linuron. In the enrichment cultures with linuron-treated soil, linuron disappeared completely after 1 week whereas no significant transformation was observed in cultures inoculated with nontreated soil even after 4 weeks. In conclusion, this study showed that both the structure and metabolic potential of soil microbial communities were clearly affected by a long-term application of urea herbicides.


2015 ◽  
Vol 12 (13) ◽  
pp. 10359-10387 ◽  
Author(s):  
W. Y. Dong ◽  
X. Y. Zhang ◽  
X. Y. Liu ◽  
X. L. Fu ◽  
F. S. Chen ◽  
...  

Abstract. Nitrogen (N) and phosphorus (P) additions to forest ecosystems are known to influence various above-ground properties, such as plant productivity and composition, and below-ground properties, such as soil nutrient cycling. However, our understanding of how soil microbial communities and their functions respond to nutrient additions in subtropical plantations is still not complete. In this study, we added N and P to Chinese fir plantations in subtropical China to examine how nutrient additions influenced soil microbial community composition and enzyme activities. The results showed that most soil microbial properties were responsive to N and/or P additions, but responses often varied depending on the nutrient added and the quantity added. For instance, there were more than 30 % greater increases in the activities of β-Glucosidase (βG) and N-acetyl-β-D-glucosaminidase (NAG) in the treatments that received nutrient additions compared to the control plot, whereas acid phosphatase (aP) activity was always higher (57 and 71 %, respectively) in the P treatment. N and P additions greatly enhanced the PLFA abundanceespecially in the N2P treatment, the bacterial PLFAs (bacPLFAs), fungal PLFAs (funPLFAs) and actinomycic PLFAs (actPLFAs) were about 2.5, 3 and 4 times higher, respectively, than in the CK. Soil enzyme activities were noticeably higher in November than in July, mainly due to seasonal differences in soil moisture content (SMC). βG or NAG activities were significantly and positively correlated with microbial PLFAs. There were also significant relationships between gram-positive (G+) bacteria and all three soil enzymes. These findings indicate that G+ bacteria is the most important microbial community in C, N, and P transformations in Chinese fir plantations, and that βG and NAG would be useful tools for assessing the biogeochemical transformation and metabolic activity of soil microbes. We recommend combined additions of N and P fertilizer to promote soil fertility and microbial activity in this kind of plantation.


mBio ◽  
2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Paul Carini ◽  
Manuel Delgado-Baquerizo ◽  
Eve-Lyn S. Hinckley ◽  
Hannah Holland‐Moritz ◽  
Tess E. Brewer ◽  
...  

ABSTRACT Few studies have comprehensively investigated the temporal variability in soil microbial communities despite widespread recognition that the belowground environment is dynamic. In part, this stems from the challenges associated with the high degree of spatial heterogeneity in soil microbial communities and because the presence of relic DNA (DNA from dead cells or secreted extracellular DNA) may dampen temporal signals. Here, we disentangle the relationships among spatial, temporal, and relic DNA effects on prokaryotic and fungal communities in soils collected from contrasting hillslopes in Colorado, USA. We intensively sampled plots on each hillslope over 6 months to discriminate between temporal variability, intraplot spatial heterogeneity, and relic DNA effects on the soil prokaryotic and fungal communities. We show that the intraplot spatial variability in microbial community composition was strong and independent of relic DNA effects and that these spatial patterns persisted throughout the study. When controlling for intraplot spatial variability, we identified significant temporal variability in both plots over the 6-month study. These microbial communities were more dissimilar over time after relic DNA was removed, suggesting that relic DNA hinders the detection of important temporal dynamics in belowground microbial communities. We identified microbial taxa that exhibited shared temporal responses and show that these responses were often predictable from temporal changes in soil conditions. Our findings highlight approaches that can be used to better characterize temporal shifts in soil microbial communities, information that is critical for predicting the environmental preferences of individual soil microbial taxa and identifying linkages between soil microbial community composition and belowground processes. IMPORTANCE Nearly all microbial communities are dynamic in time. Understanding how temporal dynamics in microbial community structure affect soil biogeochemistry and fertility are key to being able to predict the responses of the soil microbiome to environmental perturbations. Here, we explain the effects of soil spatial structure and relic DNA on the determination of microbial community fluctuations over time. We found that intensive spatial sampling was required to identify temporal effects in microbial communities because of the high degree of spatial heterogeneity in soil and that DNA from nonliving sources masks important temporal patterns. We identified groups of microbes with shared temporal responses and show that these patterns were predictable from changes in soil characteristics. These results provide insight into the environmental preferences and temporal relationships between individual microbial taxa and highlight the importance of considering relic DNA when trying to detect temporal dynamics in belowground communities.


PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0242209
Author(s):  
Muhammad Azeem ◽  
Lauren Hale ◽  
Jonathan Montgomery ◽  
David Crowley ◽  
Milton E. McGiffen

We examined the effect of a labile soil amendment, compost, and recalcitrant biochar on soil microbial community structure, diversity, and activity during turfgrass establishment. Two application rates of biochar (B1 at 12.5 t ha-1and B2 at 25 t ha-1), a 5 centimeter (cm) green waste compost treatment (CM) in top soil, a treatment with 12.5 t ha-1 biochar and 5 cm compost (B1+CM), and an unamended control (CK) treatment were prepared and seeded with tall fescue. Overall, results of phospholipid fatty acid analysis (PLFA) profiling and Illumina high-throughput sequencing of 16S rRNA genes amplified from soil DNA revealed significant shifts in microbial community structures in the compost amended soils whereas in biochar amended soils communities were more similar to the control, unamended soil. Similarly, increases in enzymatic rates (6–56%) and nitrogen-induced respiration (94%) were all largest in compost amended soils, with biochar amended soils exhibiting similar patterns to the control soils. Both biochar and compost amendments impacted microbial community structures and functions, but compost amendment, whether applied alone or co-applied with biochar, exhibited the strongest shifts in the microbial community metrics examined. Our results suggest application of compost to soils in need of microbiome change (reclamation projects) or biochar when the microbiome is functioning and long-term goals such as carbon sequestration are more desirable.


Elem Sci Anth ◽  
2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Grace Pold ◽  
Luiz A. Domeignoz-Horta ◽  
Kristen M. DeAngelis

Soils store more carbon than the biosphere and atmosphere combined, and the efficiency to which soil microorganisms allocate carbon to growth rather than respiration is increasingly considered a proxy for the soil capacity to store carbon. This carbon use efficiency (CUE) is measured via different methods, and more recently, the 18O-H2O method has been embraced as a significant improvement for measuring CUE of soil microbial communities. Based on extrapolating 18O incorporation into DNA to new biomass, this measurement makes various implicit assumptions about the microbial community at hand. Here we conducted a literature review to evaluate how viable these assumptions are and then developed a mathematical model to test how violating them affects estimates of the growth component of CUE in soil. We applied this model to previously collected data from two kinds of soil microbial communities. By changing one parameter at a time, we confirmed our previous observation that CUE was reduced by fungal removal. Our results also show that depending on the microbial community composition, there can be substantial discrepancies between estimated and true microbial growth. Of the numerous implicit assumptions that might be violated, not accounting for the contribution of sources of oxygen other than extracellular water to DNA leads to a consistent underestimation of CUE. We present a framework that allows researchers to evaluate how their experimental conditions may influence their 18O-H2O-based CUE measurements and suggest the parameters that need further constraining to more accurately quantify growth and CUE.


2021 ◽  
Vol 3 ◽  
Author(s):  
William Overbeek ◽  
Thomas Jeanne ◽  
Richard Hogue ◽  
Donald L. Smith

The use of biological inputs in crop production systems, as complements to synthetic inputs, is gaining popularity in the agricultural industry due to increasing consumer demand for more environmentally friendly agriculture. An approach to meeting this demand is the inoculation of field crops with beneficial microbes to promote plant growth and resistance to biotic and abiotic stresses. However, the scientific literature reports inconsistent results following applications of bio-inoculant to fields. The effects of inoculation with beneficial microbes on bulk soil and rhizospheric microbial communities is often overlooked as precise monitoring of soil microbial communities is difficult. The aim of this research was to use Illumina high throughput sequencing (HTS) to shed light on bulk soil and rhizospheric microbial community responses to two commercial microbial inoculants coated onto fertilizer granules, applied to potato fields. Bulk soil samples were collected 4 days before seeding (May 27th), 7 days after seeding (June 7th), at potato shoot emergence (June 21st) and at mid-flowering (July 26th). Rhizospheric soil was collected at the mid-flowering stage. The Illumina MiSeq HTS results indicated that the bulk soil microbial community composition, especially prokaryotes, changed significantly across potato growth stages. Microbial inoculation did not affect bulk soil or rhizospheric microbial communities sampled at the mid-flowering stage. However, a detailed analysis of the HTS results showed that bulk soil and rhizospheric microbial community richness and composition were different for the first treatment block compared to the other three blocks. The spatial heterogeneity of the soil microbial community between blocks of plots was associated with potato tuber yield changes, indicating links between crop productivity and soil microbial community composition. Understanding these links could help in production of high-quality microbial inoculants to promote potato productivity.


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