scholarly journals Potential Change of Soil Microbial Diversity in Anticipated Atmospheric-CO2 Elevation Triggers Rhizosphere Activation: A Meta-analysis.

Author(s):  
Pratap Bhattacharyya ◽  
Eldho Varghese ◽  
Pradeep Kumar Dash ◽  
Soumya Ranjan Padhy ◽  
Priyabrata Santra ◽  
...  

Abstract One of the key challenges in present time to meet out growing global food demand without damaging environment under constant threats of climate-extremes. Enhancement of nutrient use efficiency and build up intrinsic system tolerance through soil microbial manipulation has gained significant international support to address this challenge. Impact of elevated carbon dioxide (CO2) on soil microbial diversities both at present and future climatic scenario in spatial and temporal scale is highly debated with respect to its effects on soil functioning, nutrients dynamics and crop productivity and its practical consequences on resource conservation and food security. We conducted a meta-analysis on global database using 572 observations from 202 studies to investigate the effects of elevated CO2 on soil microbial biomass carbon (MBC), yield and structural (soil microbial populations) and functional (soil enzymatic activities) diversities across 22 countries and 108 crop species. Overall, our results revealed that MBC and functional diversity increases with elevated atmospheric-CO2 irrespective of temperature zone and crop type. However, data trends showed structural diversity has been gradually adapted under elevated CO2 across the region over decadal scale. Anticipated elevation of atmospheric CO2 increase rhizospheric activities and could make soil more input demanding and more so in temperate region. Therefore, to fetch the benefits of CO2 fertilization and to meet out the higher demand both plant and soil (microbes), real time judicious nutrient supply is necessary; otherwise, soil priming, loss of fixed soil carbon reserve and land degradation might threat the future food security.

2020 ◽  
Author(s):  
Daniel P. Bebber ◽  
Victoria R. Richards

ABSTRACTThe Green Revolution of agriculture was in part driven by application of synthetic mineral fertilizers, largely supplanting organic manure as a source of the major nutrients nitrogen, phosphorous and potassium (NPK). Though enhancing crop production and global food security, fertilizers have contributed to soil acidification, eutrophication of water bodies, and greenhouse gas emissions. Organic agriculture, employing manures or composts, has been proposed as a way of mitigating these undesirable effects. Of particular interest is the effect of fertilizer regime on soil microbes, which are key to nutrient cycling, plant health and soil structure. Meta-analyses of experimental studies indicate that mineral fertilizer increases soil microbial biomass over unfertilized controls, and that organic fertilizers increase microbial biomass and activity over mineral fertilizers. However, the effect of fertilizers on soil microbial diversity remains poorly understood. Since biological diversity is an important determinant of ecosystem function and a fundamental metric in community ecology, the effects of fertilizer regimes on soil microbial diversity are of theoretical and applied interest. Here, we conduct a meta-analysis of 31 studies reporting microbial diversity metrics in mineral fertilized (NPK), organically fertilized (ORG) and unfertilized control (CON) soils. Of these studies, 26 reported taxonomic diversity derived from sequencing, gradient gel electrophoresis, RFLP, or dilution plate assay. Functional diversity, derived from Biolog Ecoplate™ measures of carbon substrate metabolism, was reported in 8 studies, with 3 studies reporting both diversity metrics. We found that functional diversity was on average 2.6 % greater in NPK compared with CON, 6.8 % greater in ORG vs CON and 3.6 % greater in ORG vs NPK. Prokaryote taxonomic diversity was not significantly different between NPK and CON, 4.2 % greater in ORG vs CON and 4.6 % greater in ORG vs. NPK. Fungal taxonomic diversity was not significantly different between NPK or ORG vs CON, but 5.4 % lower between ORG and NPK. There was very high residual heterogeneity in all meta-analyses of soil diversity, suggesting that a large amount of further research with detailed analysis of soil properties is required to fully understand the influence of fertilizer regimes on microbial diversity and ecosystem function.


Author(s):  
Arpitha Shankar

Soil is a treasure trove of microbial variety, and bio-inoculants have the potential to improve the performance of horticultural crops under biotic and abiotic stress by boosting soil microbial diversity. Bio-inoculants are being developed to increase the diversity of soil microbes. The combined effects of bio-inoculants, on the other hand, result in the expansion of vegetation in the surrounding environment. Previous study on arbuscular mycorrhizal fungus has shown the existence of agronomic and biochemical characteristics in horticultural crop species (AMF). Through the development of enhanced technologies for the analysis of RNA or DNA from soil, we may acquire a deeper knowledge of the microbiological diversity and functions of the planet, which are difficult to find using traditional societal approaches. It is not possible to uncover a full database of purposeful genetics, which includes both soil microorganisms and deliberate genetics. This is true for almost every soil type or circumstance. As a result of this review, this study offers suggestions for the use of bio-inoculants, the benefits of doing so, regular research strategies, and long-term research directions.


Diversity ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 112
Author(s):  
Gordon F. Custer ◽  
Linda T. A. van Diepen

Plant invasion has proven to be a significant driver of ecosystem change, and with the increased probability of invasion due to globalization, agricultural practices and other anthropogenic causes, it is crucial to understand its impact across multiple trophic levels. With strong linkages between above and belowground processes, the response of soil microorganisms to plant invasion is the next logical step in developing our conceptual understanding of this complex system. In our study, we utilized a meta-analytical approach to better understand the impacts of plant invasion on soil microbial diversity. We synthesized 70 independent studies with 23 unique invaders across multiple ecosystem types to search for generalizable trends in soil microbial α-diversity following invasion. When possible, soil nutrient metrics were also collected in an attempt to understand the contribution of nutrient status shifts on microbial α-diversity. Our results show plant invasion to have highly heterogenous and limited impacts on microbial α-diversity. When taken together, our study indicates soil microbial α-diversity to remain constant following invasion, contrary to the aboveground counterparts. As our results suggest a decoupling in patterns of below and aboveground diversity, future work is needed to examine the drivers of microbial diversity patterns following invasion.


Pedobiologia ◽  
2016 ◽  
Vol 59 (4) ◽  
pp. 215-223 ◽  
Author(s):  
Zander Samuel Venter ◽  
Karin Jacobs ◽  
Heidi-Jayne Hawkins

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sunil Kumar ◽  
Ram Swaroop Meena ◽  
Rakesh Kumar Singh ◽  
Tariq Muhammad Munir ◽  
Rahul Datta ◽  
...  

AbstractFarmers are not growing diversified crops and applying huge amounts of agrochemicals and imbalanced fertilizers in the rice-wheat cropping system (RWCS), since the 1960s. The objective of this study was to evaluate the microbial and nutrient dynamics in Indian mustard (Brassica juncea L.) under various sowing environments and nutrient sources during Rabi season (October–March), 2015–2016. The experiment was laid out in the split-plot design with three sowing dates in main-plots, and eight nutrient sources in sub-plots. The maximum bacteria, fungi, and actinomycetes population, soil microbial biomass carbon (SMBC), dehydrogenase activities, and available nitrogen, phosphorus, potassium, and sulphur (NPKS) were recorded on November 17 sown crop, and the lowest was observed on December 7 sowing during both the years, and in the pooled analysis. Furthermore, applied nutrient sources, highest bacteria, fungi, and actinomycetes population, available NPKS, SMBC, and dehydrogenase activity were observed in 75% recommended dose of fertilizers (RDF) + 25% N through pressmud (PM) + Azotobacto + phosphorus solubilizing bacteria (PSB) than other nutrient sources. In conclusion, high demand and cost of chemical fertilizers can be replaced by 25% amount easily and locally available organic manures like PM compost to sustain the soil health and crop productivity. It will be helpful to restore the soil biodiversity in the RWCS and provide a roadmap for the researchers, government planners, and policymakers for the use of PM as a source of organic matter and nutrients.


2021 ◽  
Vol 3 ◽  
Author(s):  
Calvin Cornell ◽  
Vasilis Kokkoris ◽  
Andrew Richards ◽  
Christina Horst ◽  
Daniel Rosa ◽  
...  

There is a global industry built upon the production of “bioinoculants,” which include both bacteria and fungi. The recent increase in bioinoculant uptake by land users coincides with a drive for more sustainable land use practices. But are bioinoculants sustainable? These microbes are believed to improve plant performance, but knowledge of their effect on resident microbial communities is scant. Without a clear understanding of how they affect soil microbial communities (SMC), their utility is unclear. To assess how different inoculation practices may affect bioinoculant effects on SMC, we surveyed the existing literature. Our results show that bioinoculants significantly affect soil microbial diversity and that these effects are mediated by inoculant type, diversity, and disturbance regime. Further, these changes to soil microbes affect plant outcomes. Knowledge that these products may influence crop performance indirectly through changes to soil microbial diversity attests to the importance of considering the soil microbiome when assessing both bioinoculant efficacy and threats to soil ecosystems.


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