scholarly journals Differential mechanisms underlying responses of soil bacterial and fungal communities to nitrogen and phosphorus inputs in a subtropical forest

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7631 ◽  
Author(s):  
Yong Li ◽  
Dashuan Tian ◽  
Jinsong Wang ◽  
Shuli Niu ◽  
Jing Tian ◽  
...  

Atmospheric nitrogen (N) deposition and phosphorus (P) addition both can change soil bacterial and fungal community structure with a consequent impact on ecosystem functions. However, which factor plays an important role in regulating responses of bacterial and fungal community to N and P enrichments remains unclear. We conducted a manipulative experiment to simulate N and P inputs (10 g N · m−2 · yr−1 NH4NO3 or 10 g P · m−2 · yr−1 NaH2PO4) and compared their effects on soil bacterial and fungal species richness and community composition. The results showed that the addition of N significantly increased NH4+ and Al3+ by 99.6% and 57.4%, respectively, and consequently led to a decline in soil pH from 4.18 to 3.75 after a 5-year treatment. P addition increased Al3+ and available P by 27.0% and 10-fold, respectively, but had no effect on soil pH. N addition significantly decreased bacterial species richness and Shannon index and resulted in a substantial shift of bacterial community composition, whereas P addition did not. Neither N nor P addition changed fungal species richness, Shannon index, and fungal community composition. A structural equation model showed that the shift in bacterial community composition was related to an increase in soil acid cations. The principal component scores of soil nutrients showed a significantly positive relationship with fungal community composition. Our results suggest that N and P additions affect soil bacterial and fungal communities in different ways in subtropical forest. These findings highlight how the diversity of microbial communities of subtropical forest soil will depend on future scenarios of anthropogenic N deposition and P enrichment, with a particular sensitivity of bacterial community to N addition.

Author(s):  
Weiwei Yu ◽  
Yinhong Hu ◽  
Bowen Cui ◽  
Yuanyuan Chen ◽  
Xiaoke Wang

Pavements have remarkable effects on topsoil micro-organisms, but it remains unclear how subsoil microbial communities respond to pavements. In this study, ash trees (Fraxinus Chinensis) were planted on pervious pavement (PP), impervious pavement (IPP), and non-pavement (NP) plots. After five years, we determined the soil bacterial community composition and diversity by high-throughput sequencing of the bacterial 16S rRNA gene. The results of our field experiment reveal that the presence of pavement changed soil bacterial community composition and decreased the Shannon index, but had no impact on the Chao 1 at the 0–20 cm layer. However, we achieved the opposite result at a depth of 20–80 cm. Furthermore, there was a significant difference in bacterial community composition using the Shannon index and the Chao 1 at the 80–100 cm layer. Soil total carbon (TC), total nitrogen (TN), available phosphorus (AP), NO3−-N, and available potassium (AK) were the main factors that influenced soil bacterial composition and diversity across different pavements. Soil bacterial composition and diversity had no notable difference between PP and IPPs at different soil layers. Our results strongly indicate that pavements have a greater impact on topsoil bacterial communities than do subsoils, and PPs did not provide a better habitat for micro-organisms when compared to IPPs in the short term.


2018 ◽  
Author(s):  
Nicole Sukdeo ◽  
Ewing Teen ◽  
P. Michael Rutherford ◽  
Hugues B. Massicotte ◽  
Keith N. Egger

AbstractSoils contain microbial inhabitants that differ in sensitivity to anthropogenic modification. Soil reclamation relies on monitoring these communities to evaluate ecosystem functions recovery post-disturbance. DNA metabarcoding and soil enzyme assays provide information about microbial functional guilds and organic matter decomposition activities respectively. However bacterial communities, fungal communities, and enzyme activities may not be equally informative for monitoring reclaimed soils. We compared effects of disturbance regimes applied to forest soils on fungal community composition, bacterial community composition, and potential hydrolase activities (N-acetyl-β-D-glucosaminidase, acid phosphatase, and cellobiohydrolase) at two times (14 days and 5 months post-disturbance) and depths (LFH versus mineral soil). Using disturbance versus control comparisons allowed us to identify genus-level disturbance-indicators and shifts in hydrolase activity levels. We observed declines in disturbed LFH fungal biomass (ergosterol) and declines in ectomycorrhizal fungi abundance across all disturbed samples, which prompted us to consider necromass-induced (fungal, root) saprotroph increases as disturbance indicators. Fungal community composition strongly shifted away from ecotmycorrhizal dominance to saprotroph dominance (i.e. increasedMortierella, andUmbelopsis) in disturbed plots at 5 months, while bacterial community composition did not shift to distinguish control plots from disturbed ones at either sampling time. Soil potential hydrolase data mainly indicated that mixing LFH material into mineral soil increases the measured activity levels compared to control and replaced mineral soil. Bacterial saprotrophs previously associated with mycelial necromass were detected across multiple regimes as disturbance indicators at 14 days post-disturbance. Our results confirm that ectomycorrhizal fungal genera are sensitive and persistently impacted by soil physical disturbances. Increases in saprotrophic bacterial genera are detectable 14 days pot-disturbance but only a few persist as disturbance indicators after several months. Potential hydrolase activities appear to be most useful for detecting the transfer of decomposition hotspots into mineral soils.


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.


2018 ◽  
Vol 98 (4) ◽  
pp. 716-723 ◽  
Author(s):  
Laura N. Bugiel ◽  
Stuart W. Livingstone ◽  
Marney E. Isaac ◽  
Roberta R. Fulthorpe ◽  
Adam R. Martin

Soil microbial diversity is expected to be altered by the establishment of invasive plant species, such as dog-strangling vine (DSV) [Vincetoxicum rossicum (Apocynaceae)]. However, in urban ecosystems where DSV invasion is high, there is little research evaluating the impacts of DSV and other anthropogenic disturbances on microbial diversity. Our study was based in Rouge National Urban Park, Canada, where we used terminal restriction fragment length polymorphism data to evaluate (i) if DSV has a detectable impact on soil bacterial community composition and (ii) if these impacts occur independently of other anthropogenic change or soil characteristics. Variation in soil bacterial communities was greatly reduced in DSV-invaded sites vs. less-invaded sites. The degree of DSV invasion independently explained 23.8% of variation in bacterial community composition: a value similar to the explanatory power of proximity to roadways (which explained 22.6% of the variation in community composition), and considerably greater than soil parameters (pH, moisture, carbon, and nitrogen concentrations) which explained only between 6.0% and 10.0% of variation in bacterial community composition. Our findings indicate that DSV influences soil bacterial community composition independent of other anthropogenic disturbances and soil parameters, with potential impacts on multiple facets of plant–soil interactions and plant invasion dynamics.


2019 ◽  
Vol 7 (2) ◽  
pp. 47 ◽  
Author(s):  
Zhen-Shan Deng ◽  
Bao-Cheng Zhang ◽  
Xiang-Ying Qi ◽  
Zhi-Hong Sun ◽  
Xiao-Long He ◽  
...  

Pennisetum sinese, a source of bio-energy with high biomass production, is a species that contains high crude protein and will be useful for solving the shortage of forage grass after the implementation of “Green for Grain” project in the Loess plateau of Northern Shaanxi in 1999. Plants may receive benefits from endophytic bacteria, such as the enhancement of plant growth or the reduction of plant stress. However, the composition of the endophytic bacterial community associated with the roots of P. sinese is poorly elucidated. In this study, P. sinese from five different samples (Shaanxi province, SX; Fujian province, FJ; the Xinjiang Uyghur autonomous prefecture, XJ and Inner Mongolia, including sand (NS) and saline-alkali land (NY), China) were investigated by high-throughput next-generation sequencing of the 16S rDNA V3-V4 hypervariable region of endophytic bacteria. A total of 313,044 effective sequences were obtained by sequencing five different samples, and 957 effective operational taxonomic units (OTUs) were yielded at 97% identity. The phylum Proteobacteria, the classes Gammaproteobacteria and Alphaproteobacteria, and the genera Pantoea, Pseudomonas, Burkholderia, Arthrobacter, Psychrobacter, and Neokomagataea were significantly dominant in the five samples. In addition, our results demonstrated that the Shaanxi province (SX) sample had the highest Shannon index values (3.795). We found that the SX (308.097) and NS (126.240) samples had the highest and lowest Chao1 richness estimator (Chao1) values, respectively. Venn graphs indicated that the five samples shared 39 common OTUs. Moreover, according to results of the canonical correlation analysis (CCA), soil total carbon, total nitrogen, effective phosphorus, and pH were the major contributing factors to the difference in the overall composition of the bacteria community in this study. Our data provide insights into the endophytic bacteria community composition and structure of roots associated with P. sinese. These results might be useful for growth promotion in different samples, and some of the strains may have the potential to improve plant production in future studies.


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