scholarly journals Organic Amendments and Sampling Date Influences on Soil Bacterial Community Composition and Their PredictiveFunctional Profiles in an Olive Grove Ecosystem

Agriculture ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1178
Author(s):  
Laura L. de Sosa ◽  
Beatriz Moreno ◽  
Rafael Alcalá Alcalá Herrera ◽  
Marco Panettieri ◽  
Engracia Madejón ◽  
...  

A collapse of soil microbial diversity, mainly due to chemical inputs, has been reported to lead to the degradation of conventional agroecosystems. The use of compost from urban and agricultural waste management, in order to achieve a net gain in the storage of C, is an adequate management of agricultural soils, especially in rainfed conditions. However, the great variability of composts of different maturity and origins and of the soils to which they are added limits the ability to predict the impact of these amendments on the dynamics of soil microbial communities. This study was designed to gain insights on the effect of exogenous organic matter management on the soil bacterial community and its contribution to key functions relevant to agricultural soils. To achieve this, two different types of compost (alperujo or biosolids composts) at two doses were used as soil amendments twice for 3 years in a rainfed olive grove ecosystem. A metagenomic analysis was carried out to assess the abundance and composition of the soil bacterial communities and predicted functions. We only detected a minor and transitory effect on the bacterial abundance of the soil, the structure of the community and the potential functions, less related to the dose or the type of compost than to seasonal variations. Although the result suggests that the soil bacteria were highly resilient, promoting community stability and functional resilience after the addition of the two composts, more efforts are necessary to assess not only the resulting soil microbial community after organic fertilization but the intrinsic microbial community within the organic amendment that acts as an inoculum, and to what extent the changes in its dose could lead to the functionality of the soil.

2021 ◽  
Author(s):  
Jun Li ◽  
Xiaoyu Cheng ◽  
Wei Chen ◽  
Hanjie Zhang ◽  
Tianlang Chen ◽  
...  

Abstract Continuous cropping of cut chrysanthemum causes soil degradation and chrysanthemum quality decline, but the biotic and abiotic mechanisms behind it remain unclear. This impedes our ability to assess the true effects of continuous cropping on agricultural soil functions and our ability to repair impaired soils. Here we examined the impact of different replanting years on microbial communities and enzyme activities in rhizosphere soil of cut chrysanthemum (Chrysanthemum morifolium). Our results showed that soil total nitrogen (TN) and organic carbon (SOC) contents were significantly lower in the soil with 12 years of continuous cropping (Y12) than that in the soil with 1 year of cropping (Y1). Compared with Y1, Y12 treatment decreased alkaline phosphatase and β -glucosidase by 12.1 and 24.4%, but increased the activities of soil urease and catalase by 98.2 and 34.8%, respectively. Soil bacterial populations in Y6 (continuous cropping for 6 years) and Y12 treatments decreased by 52.3 and 87.5% compared with that in Y1 treatment. Moreover, the bacterial α-diversity (Shannon index) significantly decreased by 37.3 and 57.6% over 6 and 12 years of continuous cropping, respectively. Long-term monoculture cropping shifted the bacterial community composition, with decreased abundances of dominant phyla such as Proteobacteria and Acidobacteria, but with an increase in the relative abundances of Actinobacteria and Chloroflexi, and Gemmatimonadetes. Moreover, Y6 and Y12 treatments harbored less microbial network complexity, lower bacterial taxa, and fewer linkages among bacterial taxa, relative to Y1. Soil pH, SOC, and TN were the main edaphic factors affecting soil bacterial community compositions and diversity. Overall, our results demonstrate that continuous cropping has a significant negative impact on soil microbial diversity and complexity.


2019 ◽  
Vol 11 (14) ◽  
pp. 3888
Author(s):  
Prudence Bararunyeretse ◽  
Yan Zhang ◽  
Hongbing Ji

Metals and mineral flotation collector’s toxicity to the soil living system greatly compromise the sustainability of mining and ore processing. Their effects on the soil microbial community, the most active soil component, remain less understood and addressed particularly with regards to xanthates and their combination with metals. This study analyzed the interactive effects of Ni and xanthates, potassium ethyl xanthate and sodium isopropyl xanthate, on the soil bacterial community through an efficient molecular biology-based technique, the Miseq (Illumina). Both soil microbial community diversity and structure were more affected by xanthates than by Ni. The five most dominant phyla, representing 96.31% of the whole bacterial community, comprised Proteobacteria (54.16%), Firmicutes (17.51%), Actinobacteria (15.59%), Acidobacteria (4.87%), and Chloroflexi (4.16%). Different soil treatments exhibited greater difference in the species abundance/dominance than in the species numbers. Proteobacteria was the most dominant in the presence of xanthates, individually or in mixtures with nickel, while Firmicutes exhibited its highest proportion in the Ni/xanthate-treated samples. The most abundant and proportionally different bacterial species between different treatments were presented. The most abundant bacterial strains identified should be explored more for their potential application in biomining and for the prediction and biologically-based treatment and remediation of Ni and xanthate-contaminated systems.


2006 ◽  
Vol 72 (12) ◽  
pp. 7804-7812 ◽  
Author(s):  
Martin Hartmann ◽  
Franco Widmer

ABSTRACT Changes in the diversity and structure of soil microbial communities may offer a key to understanding the impact of environmental factors on soil quality in agriculturally managed systems. Twenty-five years of biodynamic, bio-organic, or conventional management in the DOK long-term experiment in Switzerland significantly altered soil bacterial community structures, as assessed by terminal restriction fragment length polymorphism (T-RFLP) analysis. To evaluate these results, the relation between bacterial diversity and bacterial community structures and their discrimination potential were investigated by sequence and T-RFLP analyses of 1,904 bacterial 16S rRNA gene clones derived from the DOK soils. Standard anonymous diversity indices such as Shannon, Chao1, and ACE or rarefaction analysis did not allow detection of management-dependent influences on the soil bacterial community. Bacterial community structures determined by sequence and T-RFLP analyses of the three gene libraries substantiated changes previously observed by soil bacterial community level T-RFLP profiling. This supported the value of high-throughput monitoring tools such as T-RFLP analysis for assessment of differences in soil microbial communities. The gene library approach also allowed identification of potential management-specific indicator taxa, which were derived from nine different bacterial phyla. These results clearly demonstrate the advantages of community structure analyses over those based on anonymous diversity indices when analyzing complex soil microbial communities.


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.


2021 ◽  
Vol 71 (1) ◽  
Author(s):  
Hongbin Zhao ◽  
Wenling Zheng ◽  
Shengwei Zhang ◽  
Wenlong Gao ◽  
Yueyue Fan

Abstract Purpose Soil microorganisms play an indispensable role in the material and energy cycle of grassland ecosystems. The abundance of these organisms vary according to environmental factors, such as time of year and soil depth. There have been few studies on the transformation of soil microbial communities in degraded typical steppe according to these temporal and spatial changes. In this study, we analyze the community structure and diversity of soil bacteria and fungi, and the impact of these changing temporal and spatial factors upon the community structure. Methods From May to September 2018, we collected 90 soil samples from different depths (10, 20, and 30 cm) from the typical degraded steppe area of Xilingol. We carried out studies on soil physical and chemical properties and soil microbial diversity using high-throughput sequencing technology. Results We found that depth significantly affected abundance and diversity of bacteria and fungi. Bacteria and fungi diversity at 10 cm was higher than that at 20 cm and 30 cm. The abundance of Acidobacteria, Proteobacteria, Actinomycetes, Ascomycetes, and Basidiomycetes varies significantly with depth. In addition, soil pH increased significantly with increasing depth, while soil organic matter (SOM), available nitrogen (AN), volume water content of soil (VWC), and soil temperature (ST) decreased significantly with increasing depth. Finally, the depth, total organic carbon (TOC), and AN had a significant impact on the bacterial and fungal communities’ abundance (p < 0.05). Conclusions Spatial heterogeneity (in soil depth) is more significant than the time of year (month) in predicting changes in microbial community composition and soil properties. SOM, VWC, and the abundance of Proteobacteria and Actinomycetes positively correlate with soil depth, while pH and the abundance of Acidobacteria, Ascomycetes, and Basidiomycetes negatively correlate with soil depth. We speculate that SOM and VWC account for the variations in the abundance of Acidobacteria and Proteobacteria, while pH causes variations in the abundance of Actinomycetes, Ascomycetes and Basidiomycota.


2021 ◽  
Vol 6 (4) ◽  
pp. 119-125
Author(s):  
Acacio Aparecido Navarrete ◽  
Eliamar Aparecida Nascimbém Pedrinho ◽  
Luciano Takeshi Kishi ◽  
Camila Cesário Fernandes ◽  
Victoria Romancini Toledo ◽  
...  

Nowadays, due to the expansion of agricultural borders, it is highly desirable to increase the sustained productivity of sugarcane cultivars using the knowledge of soil microbial communities. In this study, twelve shotgun metagenomic datasets based on genomic DNA from soil were analyzed using the Metagenomics Rapid Annotation using Subsystem Technology (MG-RAST) and Statistical Analysis of Metagenomic Profiles (STAMP) to assess differential responses for the total soil bacterial community composition and nitrogen-cycling microbial community functional potential in soils from sugarcane field with pre-harvest burning and adjacent forest in dry and wet seasons in Southeast Brazil. The soil bacterial community revealed higher abundance for Actinobacteria in forest soil than sugarcane soil in dry and wet seasons, and an opposite pattern for Proteobacteria and Planctomycetes in these soils in both seasons. The results obtained in this study based on the KEEG map suggest that the forest soil has a higher nitrogen-cycling microbial community functional potential compared to the sugarcane soil, independently of the season. The gene sequences associated with carbohydrate metabolism were the most frequent in all soil metagenomes. Taken together, the results confirm previous findings regarding the effects of forest conversion to sugarcane production area, providing new insights regarding to this conversion through the prism of the seasonality and pre-harvesting method on microbially mediated nitrogen cycle in sugarcane production fields.


2021 ◽  
Vol 12 (1) ◽  
pp. 157-172
Author(s):  
Shankar G. Shanmugam ◽  
Normie W. Buehring ◽  
Jon D. Prevost ◽  
William L. Kingery

Our understanding on the effects of tillage intensity on the soil microbial community structure and composition in crop production systems are limited. This study evaluated the soil microbial community composition and diversity under different tillage management systems in an effort to identify management practices that effectively support sustainable agriculture. We report results from a three-year study to determine the effects on changes in soil microbial diversity and composition from four tillage intensity treatments and two residue management treatments in a corn-soybean production system using Illumina high-throughput sequencing of 16S rRNA genes. Soil samples were collected from tillage treatments at locations in the Southern Coastal Plain (Verona, Mississippi, USA) and Southern Mississippi River Alluvium (Stoneville, Mississippi, USA) for soil analysis and bacterial community characterization. Our results indicated that different tillage intensity treatments differentially changed the relative abundances of bacterial phyla. The Mantel test of correlations indicated that differences among bacterial community composition were significantly influenced by tillage regime (rM = 0.39, p ≤ 0.0001). Simpson’s reciprocal diversity index indicated greater bacterial diversity with reduction in tillage intensity for each year and study location. For both study sites, differences in tillage intensity had significant influence on the abundance of Proteobacteria. The shift in the soil bacterial community composition under different tillage systems was strongly correlated to changes in labile carbon pool in the system and how it affected the microbial metabolism. This study indicates that soil management through tillage intensity regime had a profound influence on diversity and composition of soil bacterial communities in a corn-soybean production system.


2021 ◽  
Author(s):  
Alin Song ◽  
Zimin Li ◽  
Fenliang Fan

&lt;p&gt;Returning crop straw into soil is an important practice to balance biogenic and bioavailable silicon (Si) pool in paddy, which is crucial for rice healthy growth. However, it remains elusive how straw return affects Si bioavailability, its uptake, and rice yield, owing to little knowledge about soil microbial communities responsible for straw degradation. Here, we investigated the change of soil Si fractions and microbial community in a 39-year-old paddy field amended by a long-term straw return. Results showed that rice straw-return significantly increased soil bioavailable Si and rice yield to from 29.9% to 61.6% and from 14.5% to 23.6%, respectively, compared to NPK fertilization alone. Straw return significantly altered soil microbial community abundance. Acidobacteria was positively and significantly related to amorphous Si, while Rokubacteria at the phylum level, Deltaproteobacteria and Holophagae at the class level were negatively and significantly related to organic matter adsorbed and Fe/Mn-oxide combined Si in soils. Redundancy analysis of their correlations further demonstrated that Si status significantly explained 12% of soil bacterial community variation. These findings suggest that soil bacteria community and diversity interact with Si mobility via altering its transformation, resulting in the balance of various nutrient sources to drive biological silicon cycle in agroecosystem.&lt;/p&gt;


2020 ◽  
Vol 66 (4) ◽  
pp. 263-273
Author(s):  
Julien Saavedra-Lavoie ◽  
Anne de la Porte ◽  
Sarah Piché-Choquette ◽  
Claude Guertin ◽  
Philippe Constant

Trace gas uptake by microorganisms controls the oxidative capacity of the troposphere, but little is known about how this important function is affected by changes in soil microbial diversity. This article bridges that knowledge gap by examining the response of the microbial community-level physiological profiles (CLPPs), carbon dioxide (CO2) production, and molecular hydrogen (H2) and carbon monoxide (CO) oxidation activities to manipulation of microbial diversity in soil microcosms. Microbial diversity was manipulated by mixing nonsterile and sterile soil with and without the addition of antibiotics. Nonsterile soil without antibiotics was used as a reference. Species composition changed significantly in soil microcosms as a result of dilution and antibiotic treatments, but there was no difference in species richness, according to PCR amplicon sequencing of the bacterial 16S rRNA gene. The CLPP was 15% higher in all dilution and antibiotic treatments than in reference microcosms, but the dilution treatment had no effect on CO2 production. Soil microcosms with dilution treatments had 58%–98% less H2 oxidation and 54%–99% lower CO oxidation, relative to reference microcosms, but did not differ among the antibiotic treatments. These results indicate that H2 and CO oxidation activities respond to compositional changes of microbial community in soil.


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