Bacteria in agricultural soils: Diversity, role and future perspectives

2003 ◽  
Vol 83 (Special Issue) ◽  
pp. 303-309 ◽  
Author(s):  
E. Topp

Bacteria in soil are very diverse, very numerous, and functionally important, and have historically been an important object of research by Canadian microbiologists. Only a small fraction of bacteria in soils are amenable to culturing in the laboratory, limiting the ability to study these organisms. Canadian scientists have contributed to the development and implementation of both nucleic acidbased and chemical biomarker-based methods now widely used for assessing soil microbial biodiversity without the need for isolation and cultivation. Pesticide degradation, and the cycling of nitrogen in soils are used here to illustrate the significance of bacterial biodiversity to soil functions relevant to human and environmental health, and crop production . There remains much to be discovered about the genetic and functional biodiversity of soil bacteria, and much to be gained from this knowledge. A number of recommendations are made for future research in soil bacteriology. Key words: Soil quality, bacteria, microbial biodiversity, pesticide biodegradation, nitrogen cycling.

2021 ◽  
Vol 941 (1) ◽  
pp. 012029
Author(s):  
E Abakumov ◽  
A Kimeklis ◽  
G Gladkov ◽  
E Andronov ◽  
E Morgun

Abstract Soil cover of the northern most regions of Eurasia are considered as underestimated in terms of their possible role in expansions of current agriculture to the cryolithozone. In this context, abandoned agricultural soils of Yamal region were investigated in terms of morphology, chemistry and taxonomy microbiome compositions and compared in these terms with mature tundra and taiga soils of pristine environments. The level of soil fertility was low in all cases – former agricultural soils and pristine ones. The level of microorganism’s biodiversity was higher in soils of agricultural lands. This fact indicates that the agricultural soil treatment in polar terrestrial ecosystem results in increasing of soil microbial biodiversity due to diversification of ecological niches. Also the is an essential lack of nitrogen sources in all permafrost affected soils studied.


2021 ◽  
Vol 10 (1) ◽  
pp. 456-475
Author(s):  
Efat Zohra ◽  
Muhammad Ikram ◽  
Ahmad A. Omar ◽  
Mujahid Hussain ◽  
Seema Hassan Satti ◽  
...  

Abstract In the present era, due to the increasing incidence of environmental stresses worldwide, the developmental growth and production of agriculture crops may be restrained. Selenium nanoparticles (SeNPs) have precedence over other nanoparticles because of the significant role of selenium in activating the defense system of plants. In addition to beneficial microorganisms, the use of biogenic SeNPs is known as an environmentally friendly and ecologically biocompatible approach to enhance crop production by alleviating biotic and abiotic stresses. This review provides the latest development in the green synthesis of SeNPs by using the results of plant secondary metabolites in the biogenesis of nanoparticles of different shapes and sizes with unique morphologies. Unfortunately, green synthesized SeNPs failed to achieve significant attention in the agriculture sector. However, research studies were performed to explore the application potential of plant-based SeNPs in alleviating drought, salinity, heavy metal, heat stresses, and bacterial and fungal diseases in plants. This review also explains the mechanistic actions that the biogenic SeNPs acquire to alleviate biotic and abiotic stresses in plants. In this review article, the future research that needs to use plant-mediated SeNPs under the conditions of abiotic and biotic stresses are also highlighted.


Minerals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 373
Author(s):  
Jonathan Suazo-Hernández ◽  
Erwin Klumpp ◽  
Nicolás Arancibia-Miranda ◽  
Patricia Poblete-Grant ◽  
Alejandra Jara ◽  
...  

Engineered nanoparticles (ENPs) present in consumer products are being released into the agricultural systems. There is little information about the direct effect of ENPs on phosphorus (P) availability, which is an essential nutrient for crop growthnaturally occurring in agricultural soils. The present study examined the effect of 1, 3, and 5% doses of Cu0 or Ag0 ENPs stabilized with L-ascorbic acid (suspension pH 2–3) on P ad- and desorption in an agricultural Andisol with total organic matter (T-OM) and with partial removal of organic matter (R-OM) by performing batch experiments. Our results showed that the adsorption kinetics data of H2PO4− on T-OM and R-OM soil samples with and without ENPs were adequately described by the pseudo-second-order (PSO) and Elovich models. The adsorption isotherm data of H2PO4− from T-OM and R-OM soil samples following ENPs addition were better fitted by the Langmuir model than the Freundlich model. When the Cu0 or Ag0 ENPs doses were increased, the pH value decreased and H2PO4− adsorption increased on T-OM and R-OM. The H2PO4− desorption (%) was lower with Cu0 ENPs than Ag0 ENPs. Overall, the incorporation of ENPs into Andisols generated an increase in P retention, which may affect agricultural crop production.


2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
A. Marais ◽  
M. Hardy ◽  
M. Booyse ◽  
A. Botha

Different plants are known to have different soil microbial communities associated with them. Agricultural management practices such as fertiliser and pesticide addition, crop rotation, and grazing animals can lead to different microbial communities in the associated agricultural soils. Soil dilution plates, most-probable-number (MPN), community level physiological profiling (CLPP), and buried slide technique as well as some measured soil physicochemical parameters were used to determine changes during the growing season in the ecosystem profile in wheat fields subjected to wheat monoculture or wheat in annual rotation with medic/clover pasture. Statistical analyses showed that soil moisture had an over-riding effect on seasonal fluctuations in soil physicochemical and microbial populations. While within season soil microbial activity could be differentiated between wheat fields under rotational and monoculture management, these differences were not significant.


2021 ◽  
Vol 16 (3) ◽  
pp. 7-13
Author(s):  
Radik Safin ◽  
Ayrat Valiev ◽  
Valeriya Kolesar

Global climatic changes have a negative impact on the development of all sectors of the economy, including agriculture. However, the very production of agricultural products is one of the most important sources of greenhouse gases entering the atmosphere. Taking into account the need to reduce the “carbon footprint” in food production, a special place is occupied by the analysis of the volume of greenhouse gas emissions and the development of measures for their sequestration in agriculture. One of the main directions for reducing emissions and immobilizing greenhouse gases is the development of special techniques for their sequestration in the soil, including those used in agriculture. Adaptation of existing farming systems for this task will significantly reduce the “carbon footprint” from agricultural production, including animal husbandry. The development of carbon farming allows not only to reduce greenhouse gas emissions, but also to significantly increase the level of soil fertility, primarily by increasing the content of organic matter in them. As a result, it becomes possible, along with the production of crop production, to produce “carbon units” that are sold on local and international markets. The paper analyzes possible greenhouse gas emissions from agriculture and the potential for their sequestration in agricultural soils. The role of various elements of the farming system in solving the problem of reducing the “carbon footprint” is considered and ways of developing carbon farming in the Republic of Tatarstan are proposed


2013 ◽  
Vol 1 (1) ◽  
pp. 35-38 ◽  
Author(s):  
Sartaj Wani ◽  
Subhash Chand ◽  
Tahir Ali

Research on Azotobacter chroococcum spp. in crop production has manifested its significance in plant nutrition and its contribution to soil fertility. The possibility of using Azotobacter chroococcum in research experiments as microbial inoculant through production of growth substances and their effects on the plant has markedly enhanced crop production in agriculture. Being soil bacteria, Azotobacteria genus synthesizes auxins, cytokinins, and GA–like substances, and these growth materials are the primary substances controlling the enhanced growth. These hormonal substances, which originate from the rhizosphere or root surface, affect the growth of the closely associated higher plants. In order to guarantee the high effectiveness of inoculants and microbiological fertilizers it is necessary to find the compatible partners, i.e. a particular plant genotype and a particular Azotobacter strain that will form a good association.


Author(s):  
Tom Thirkell ◽  
◽  
Grace Hoysted ◽  
Ashleigh Elliott ◽  
Katie Field ◽  
...  

Arbuscular mycorrhizal fungi (AMF) form endosymbiosis with over 70 % of land plants, including most crops including cereals. These symbioses facilitate resource exchange between partners and can significantly increase plant nutrient uptake and growth, among other benefits. AMF ubiquity in agricultural soils, in addition to the many roles they are known to play in soil health, demands we consider them when discussing crop function. We discuss how AMF are capable of increasing crop acquisition of macro- and micronutrients. We examine further impacts that AMF have on root system architecture, and how this relates to nutrient acquisition. We highlight reasons why potential benefits of the symbiosis are often not realised and how this influences current perspectives on the utility of AMF. We also discuss aspects of modern agronomy practice which are deleterious to mycorrhizal functioning. Strategies are suggested by which mycorrhizas might be exploited in future highlighting future research priorities.


2021 ◽  
Author(s):  
Frederick Dadzie ◽  
Angela Moles ◽  
Todd Erickson ◽  
Miriam Munoz-Rojas

<p>Seed-based ecosystem restoration has huge potential to restore degraded lands but currently less than 10 % of directly sown seeds successfully establish in drylands. Soil microbial communities are important for improving plant establishment in degraded land. However, current methods such as soil translocation can potentially disturb the donor site. In this study, we investigated a novel non-destructive method for improving seedling growth of native plants used in restoration through seed-soil-microbial pelleting. We assessed seedling emergence and survival of <em>Triodia epactia</em> and <em>Acacia inaequilatera</em> seeds inoculated with whole soil bacteria and cyanobacteria consortia retrieved and isolated from a pristine ecosystem. A field experiment was set-up in a 35m x 40m purpose-built rain exclusion shelter that contained reconstructed soil profiles typically encountered in mine rehabilitation programs of Australia’s arid north-west. We hypothesized that inoculated seed-soil pellets would improve seedling emergence and survival of these species. After three weeks of planting, seedling emergence in microbially inoculated <em>Acacia</em> <em>inaequilatera</em> and <em>Triodia epactia</em> were 48% and 55% higher than non-inoculated seeds in bacteria and cyanobacteria, respectively. We also tested whether the use of cyanobacteria consortia as inocula promoted higher seedling emergence over whole soil bacteria. We found that there was no significant difference in seedling emergence between the microbial taxa. We show that, improving the diversity of soil microorganisms improves seedling emergence and the seed-soil pellet method used is viable to improve seed-based restoration outcomes.</p><p><strong>Key words</strong>: Seed-based restoration, microbial community, cyanobacteria, bacteria community, seedling emergence.</p>


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Anthony Horner ◽  
Samuel S. Browett ◽  
Rachael E. Antwis

AbstractModern agricultural practices have vastly increased crop production but negatively affected soil health. As such, there is a call to develop sustainable, ecologically-viable approaches to food production. Mixed-cropping of plant varieties can increase yields, although impacts on plant-associated microbial communities are unclear, despite their critical role in plant health and broader ecosystem function. We investigated how mixed-cropping between two field pea (Pisum sativum L.) varieties (Winfreda and Ambassador) influenced root-associated microbial communities and yield. The two varieties supported significantly different fungal and bacterial communities when grown as mono-crops. Mixed-cropping caused changes in microbial communities but with differences between varieties. Root bacterial communities of Winfreda remained stable in response to mixed-cropping, whereas those of Ambassador became more similar to Winfreda. Conversely, root fungal communities of Ambassador remained stable under mixed-cropping, and those of Winfreda shifted towards the composition of Ambassador. Microbial co-occurrence networks of both varieties were stronger and larger under mixed-cropping, which may improve stability and resilience in agricultural soils. Both varieties produced slightly higher yields under mixed-cropping, although overall Ambassador plants produced higher yields than Winfreda plants. Our results suggest that variety diversification may increase yield and promote microbial interactions.


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