Effects of potassium azide on soil microbial populations and soil enzymatic activities

1975 ◽  
Vol 21 (4) ◽  
pp. 565-570 ◽  
Author(s):  
W. D. Kelley ◽  
R. Rodriguez-Kabana
Keyword(s):  
Soil Enzyme ◽  
Soil Microflora ◽  
Microbial Populations ◽  
Bacterial Populations ◽  
Soil Microbial ◽  
Fungal Populations ◽  
Potassium Azide ◽  
Time Changes ◽  
Bacteria And Fungi ◽  
Microbial Numbers

Preplant applications of potassium azide (KN3) to pine nursery beds were evaluated for effect on the soil microflora and on soil enzyme activity where either plastic-sealing or water-sealing techniques were used. Two weeks after incorporation of azide (0–224 kg/ha), soil samplings revealed reduced populations of bacteria and fungi and a corresponding decline in invertase and amylase activities. These effects were proportionate to the amount of azide used and were more pronounced in plastic-sealed plots. Phosphatase activity was little affected. Five weeks after azide application, bacterial populations were higher in treated plots than in controls. Greater numbers of bacteria were recorded from plastic-sealed plots and highest populations coincided with plots receiving the highest rates of azide, regardless of the sealing technique. Fungal populations at this sampling were generally less in treated plots than in the controls, but were higher under plastic seal. At this time, changes in invertase and amylase activities did not correspond to increased microbial numbers. Sixteen weeks after applications of KN3, bacterial populations in treated plots did not differ significantly from controls, but remained higher in plastic-sealed than water-sealed plots. Fungal populations under plastic seal had changed little and remained significantly lower in treated water-sealed plots than in controls. The earlier recorded reduction in invertase and amylase activities was still evident at the final sampling.

scholarly journals Contrasting soil microbial abundance and diversity on and between pasture drill rows in the third growing season after sowing

2020 ◽  
pp. 1-10 ◽  
Author(s):  
Richard C. Hayes ◽  
Vadakattu V. S. R. Gupta ◽  
Guangdi D. Li ◽  
Mark B. Peoples ◽  
Richard P. Rawnsley ◽  
...  
Keyword(s):  
Subterranean Clover ◽  
Plant Distribution ◽  
Total Carbon ◽  
Microbial Abundance ◽  
Soil Microbial ◽  
The Third ◽  
Fungal Populations ◽  
Abundance And Diversity ◽  
Bacteria And Fungi ◽  
The Impact

Abstract Changed spatial configurations at sowing have been investigated as a strategy to minimize interspecific competition and improve the establishment and persistence of multi-species plantings in pastures, but the impact of this practice on the soil microbiome has received almost no previous research attention. Differences in populations of bacteria and fungi in the surface 10 cm of soil in the third year following pasture establishment were quantified using quantitative polymerase chain reaction and terminal restriction fragment length polymorphism methods. Populations were compared on, and between, drill rows sown to either the perennial grass phalaris (Phalaris aquatica L.), perennial legume lucerne (alfalfa; Medicago sativa L.) or the annual legume subterranean clover (Trifolium subterraneum L.). Results showed that soil microbial abundance and diversity were related to plant distribution across the field at the time of sampling and to soil chemical parameters including total carbon (C), mineral nitrogen (N), pH, and available phosphorus (P), potassium (K) and sulfur (S). Despite the 27-month lag since sowing, pasture species remained concentrated around the original drill row with very little colonization of the inter-row area. The abundance and diversity of bacterial and fungal populations were consistently greater under drill rows associated with higher total C concentrations in the surface soil compared with the inter-row areas. Our results showed that the pH and available nutrients were similar between the subterranean clover drill row and the inter-row, suggesting that soil microbial populations were not impacted directly by these soil fertility parameters, but rather were related to the presence or absence of plants. The abundance of bacteria and fungi were numerically lower under phalaris rows compared to rows sown to legumes. The richness and diversity of fungal populations were lowest between rows where lucerne was planted. Possible explanations for this observation include a lower C:N ratio of lucerne roots and/or a lack of fibrous roots at the soil surface compared to the other species, illustrating the influence of contrasting plant types on the soil microflora community. This study highlights the enduring legacy of the drill row on the spatial distribution of plants well into the pasture phase of a cropping rotation and discusses the opportunity to enhance the microbiome of cropping soils on a large scale during the pasture phase by increasing plant distribution across the landscape.

scholarly journals The influence of halophytic compost, farmyard manure and phosphobacteria on soil microflora and enzyme activities

2008 ◽  
Vol 53 (No. 4) ◽  
pp. 186-192 ◽  
Author(s):  
V. Balakrishnan ◽  
K. Venkatesan ◽  
K.C. Ravindran
Keyword(s):  
Alkaline Phosphatase ◽  
Enzyme Activities ◽  
Microbial Population ◽  
Farmyard Manure ◽  
Soil Enzyme ◽  
Soil Microflora ◽  
Soil Enzyme Activities ◽  
Chemical Fertilizers ◽  
Soil Microbial ◽  
Soil Microbial Population

Biocompost has been identified as an alternative to chemical fertilizers that increased soil microbial population and soil enzyme activities in sustainable farming. The objective of this field study was to evaluate the effect of three halophytic composts in combination with farmyard manure and phosphate solubilising bacteria (<i>Bacillus megaterium</i>) on soil microflora and enzyme activities. The results show that among nine treatments given, the application of <i>Suaeda</i> compost in combination with farmyard manure and phosphate solubilising bacteria (T<sub>9</sub>) significantly increased the soil microflora such as bacteria, fungi and actinomycetes and soil enzyme activities such as dehydrogenases, alkaline phosphatase, cellulase and urease in soil cultivated with <i>Arachis hypogaea</i>.

Effect of 1,4-Dichlorobenzene on Soil Microbial Populations and Enzyme Activities

2012 ◽  
Vol 610-613 ◽  
pp. 90-93 ◽  
Author(s):  
Hui Xing Liang ◽  
Zhao Xia Li
Keyword(s):  
Enzyme Activities ◽  
Potential Effect ◽  
Soil Samples ◽  
Microbial Populations ◽  
Wetland Soil ◽  
Soil Microbial ◽  
Bacteria And Fungi

The potential effect of 1,4-dichlorobenzene(1,4-DCB) on Microbial Populations and enzyme activities was investigated in a flooded wetland soil. The results showed that the number of actinomycetes declined significantly after the treatment of 1,4-DCB at different concentrations, and the amout of bacteria and fungi were significantly decreased in soil samples treated with higher than 200 mg/Kg. 1,4-DCB at over the range of selected concentrations could completely inhibit urease activityin the first 28 days.1,4-DCB at the concentration lower than 100 mg/Kg dried soil stimulated the activity of catalase , while the others showed an inhibition during period of incubation. Results indicated that these two enzymes are sensitive to 1,4-DCB contamination.

MANIPULATION OF BACTERIA, FUNGI AND PROTOZOA BY BIOCIDES IN LODGEPOLE PINE FOREST SOIL MICROCOSMS: EFFECTS ON ORGANISM INTERACTIONS AND NITROGEN MINERALIZATION

1986 ◽  
Vol 66 (2) ◽  
pp. 261-272 ◽  
Author(s):  
E. R. INGHAM ◽  
C. CAMBARDELLA ◽  
D. C. COLEMAN
Keyword(s):  
Forest Soil ◽  
N Mineralization ◽  
Lodgepole Pine ◽  
Mineral Soil ◽  
Pine Forest ◽  
Inorganic N ◽  
Bacterial Populations ◽  
Fungal Populations ◽  
Pine Forest Soil ◽  
Bacteria And Fungi

Biocides were applied singly and in combination to determine their effect on target and nontarget microorganisms in mineral soil from a lodgepole pine forest and to determine microbial interaction effects on N mineralization. Soil was sterilized and reinoculated with field populations of bacteria, fungi and protozoa. Streptomycin (a bactericide), fungizone (a saprophytic fungicide), chloroform (reduces protozoa and a portion of the bacteria and fungi), a combination of cygon (an acaricide), carbofuran (an insecticide-nematicide) and chloroform and a combination of streptomycin and fungizone were used. Reduction of bacteria produced the same decreases in N immobilization and increases in soil inorganic N in forest soil as observed previously in grassland soil. Further, reduction of fungi decreased N mineralization. Chloroform reduced protozoa to below detection limits, reduced bacterial populations 2- to 10-fold, but only reduced fungal populations by twofold. Despite reductions in both bacteria and fungi, NH+4-N increased similarly to streptomycin treatments where only bacteria were reduced. When fungal populations increased after a reduction in bacterial populations, inorganic N concentrations increased. However, when fungal populations were reduced, bacterial populations did not increase, suggesting that bacteria do not compete with fungi for substrates. Key words: Microbial ecology, N mineralization, streptomycin, amphotericin B, chloroform, pesticide effects, lodgepole pine soil

scholarly journals Distinct Biogeographic Patterns for Archaea, Bacteria, and Fungi along the Vegetation Gradient at the Continental Scale in Eastern China

mSystems ◽  
2017 ◽  
Vol 2 (1) ◽  
Author(s):  
Bin Ma ◽  
Zhongmin Dai ◽  
Haizhen Wang ◽  
Melissa Dsouza ◽  
Xingmei Liu ◽  
...  
Keyword(s):  
Eastern China ◽  
Soil Microbial Communities ◽  
Natural Forest ◽  
Community Diversity ◽  
Biogeographic Patterns ◽  
Soil Microbial ◽  
Continental Scale ◽  
Forest Sites ◽  
Vegetation Gradient ◽  
Bacteria And Fungi

ABSTRACT Understanding biogeographic patterns is a precursor to improving our knowledge of the function of microbiomes and to predicting ecosystem responses to environmental change. Using natural forest soil samples from 110 locations, this study is one of the largest attempts to comprehensively understand the different patterns of soil archaeal, bacterial, and fungal biogeography at the continental scale in eastern China. These patterns in natural forest sites could ascertain reliable soil microbial biogeographic patterns by eliminating anthropogenic influences. This information provides guidelines for monitoring the belowground ecosystem’s decline and restoration. Meanwhile, the deviations in the soil microbial communities from corresponding natural forest states indicate the extent of degradation of the soil ecosystem. Moreover, given the association between vegetation type and the microbial community, this information could be used to predict the long-term response of the underground ecosystem to the vegetation distribution caused by global climate change. The natural forest ecosystem in Eastern China, from tropical forest to boreal forest, has declined due to cropland development during the last 300 years, yet little is known about the historical biogeographic patterns and driving processes for the major domains of microorganisms along this continental-scale natural vegetation gradient. We predicted the biogeographic patterns of soil archaeal, bacterial, and fungal communities across 110 natural forest sites along a transect across four vegetation zones in Eastern China. The distance decay relationships demonstrated the distinct biogeographic patterns of archaeal, bacterial, and fungal communities. While historical processes mainly influenced bacterial community variations, spatially autocorrelated environmental variables mainly influenced the fungal community. Archaea did not display a distance decay pattern along the vegetation gradient. Bacterial community diversity and structure were correlated with the ratio of acid oxalate-soluble Fe to free Fe oxides (Feo/Fed ratio). Fungal community diversity and structure were influenced by dissolved organic carbon (DOC) and free aluminum (Ald), respectively. The role of these environmental variables was confirmed by the correlations between dominant operational taxonomic units (OTUs) and edaphic variables. However, most of the dominant OTUs were not correlated with the major driving variables for the entire communities. These results demonstrate that soil archaea, bacteria, and fungi have different biogeographic patterns and driving processes along this continental-scale natural vegetation gradient, implying different community assembly mechanisms and ecological functions for archaea, bacteria, and fungi in soil ecosystems. IMPORTANCE Understanding biogeographic patterns is a precursor to improving our knowledge of the function of microbiomes and to predicting ecosystem responses to environmental change. Using natural forest soil samples from 110 locations, this study is one of the largest attempts to comprehensively understand the different patterns of soil archaeal, bacterial, and fungal biogeography at the continental scale in eastern China. These patterns in natural forest sites could ascertain reliable soil microbial biogeographic patterns by eliminating anthropogenic influences. This information provides guidelines for monitoring the belowground ecosystem’s decline and restoration. Meanwhile, the deviations in the soil microbial communities from corresponding natural forest states indicate the extent of degradation of the soil ecosystem. Moreover, given the association between vegetation type and the microbial community, this information could be used to predict the long-term response of the underground ecosystem to the vegetation distribution caused by global climate change. Author Video: An author video summary of this article is available.

scholarly journals Effects of Short-Term Rice Straw Return on the Soil Microbial Community

Agriculture ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 561
Author(s):  
Enze Wang ◽  
Xiaolong Lin ◽  
Lei Tian ◽  
Xinguang Wang ◽  
Li Ji ◽  
...  
Keyword(s):  
Microbial Community ◽  
Rice Straw ◽  
Paddy Soil ◽  
Soil Microbial Community ◽  
Short Term ◽  
Soil Microbial ◽  
Microbial Network ◽  
Straw Return ◽  
Bacteria And Fungi ◽  
Main Factor

Rice straw is a byproduct of agricultural production and an important agricultural resource. However, rice straw has not yet been effectively used, and incorrect treatment methods (such as burning in the field) can cause serious damage to the environment. Studies have shown that straw returning is beneficial to soil, but there have been few studies focused on the effect of the amount of short-term straw returned on the soil microbial community. This study evaluates 0%, 50%, 75%, and 100% rice straw returned to the field on whether returning different amounts of straw in the short term would affect the diversity and composition of the soil microbial community and the correlation between bacteria and fungi. The results show that the amount of straw returned to the field is the main factor that triggers the changes in the abundance and composition of the microbial community in the paddy soil. A small amount of added straw (≤ 50% straw added) mainly affects the composition of the bacterial community, while a larger amount of added straw (> 50% straw added) mainly affects the composition of the fungal community. Returning a large amount of straw increases the microbial abundance related to carbon and iron cycles in the paddy soil, thus promoting the carbon and iron cycle processes to a certain extent. In addition, network analysis shows that returning a large amount of straw also increases the complexity of the microbial network, which may encourage more microbes to be niche-sharing and comprehensively improve the ecological environment of paddy soil. This study may provide some useful guidance for rice straw returning in northeast China.

Methodology in Accelerated Biodegradation of Herbicides

1987 ◽  
Vol 1 (4) ◽  
pp. 333-340 ◽  
Author(s):  
Ravva V. Subba-Rao ◽  
Thomas H. Cromartie ◽  
Reed A. Gray
Keyword(s):  
Quantitative Measurement ◽  
Microbial Growth ◽  
Soil Microflora ◽  
Chemical Analyses ◽  
Untreated Soil ◽  
Accelerated Degradation ◽  
Field Soils ◽  
Potential Formation ◽  
Bacteria And Fungi ◽  
Additional Index

Accelerated biodegradation of herbicides in soils can be demonstrated in the laboratory either by treating soil samples with a herbicide under conditions favorable for microbial growth or by sampling field soils soon after herbicidal treatment. Quantitative measurement of accelerated degradation of thiocarbamates in field soils is complicated by the difficulty both of obtaining a proper untreated soil and of obtaining a representative sample by proper mixing of treated soil. Both bacteria and fungi degrade thiocarbamate herbicides, and examples of either class of organisms can be isolated by suitable selection and enrichment conditions. The enzymes involved in the initial steps of thiocarbamate biodegradation seem labile and have not been characterized. Studies of accelerated biodegradation of pesticides should measure the disappearance of the parent or active herbicide using chemical analyses or bioassays. Measuring accelerated biodegradation by determining metabolites (including CO2) is complicated by potential formation of other products, by incorporation of radioactivity into soil microflora, and by complex kinetics partly due to co-metabolism of the herbicide. Additional index words: EPTC, butylate.

Responses of soil microorganisms to volatile exudates from germinating pea seeds

1985 ◽  
Vol 63 (6) ◽  
pp. 1040-1045 ◽  
Author(s):  
J. M. Norton ◽  
G. E. Harman
Keyword(s):  
Soil Microorganisms ◽  
Sclerotium Rolfsii ◽  
Hyphal Growth ◽  
Soil Microbial Activity ◽  
Soil Microflora ◽  
Natural Soil ◽  
Soil Microbial ◽  
Aged Seed ◽  
Seed Rot ◽  
Pea Seeds

Responses of soil microorganisms to volatile exudates from germinating pea seeds of differing quality were determined. Germination of sclerotia of Rhizoctonia solani and Sclerotium rolfsii and subsequent hyphal growth were stimulated by exposure to volatiles from aged but not nonaged pea seeds. Hyphae grew preferentially toward aged seeds. In natural soil, bacterial and fungal populations showed significant increases after exposure to volatiles from aged seed. For example, Fusarium spp. and Pseudomonas spp. showed increases of 79 and 2200%, respectively, over their original population levels after a 48-h exposure to volatiles. Conversely, Pythium populations and associated seed-rotting potential of soil decreased in natural soils exposed to volatiles. In autoclaved soils infested with P. ultimum (PHP4), Pythium populations increased dramatically after exposure to volatiles from aged pea seeds. In soils infested with either soil fungi or bacteria in addition to P. ultimum, Pythium levels remained constant or decreased, respectively, with time of exposure. Exposure to the volatiles from aged pea seeds stimulated soil microbial activity. These results suggest that Pythium germlings, when unable to reach a host, are subjected to microbial antagonism in the presence of the native soil microflora. A decrease in cucumber seed rot coincided with decreases in Pythium numbers.

scholarly journals Temperature Sensitivity and Composition of Nitrate-Reducing Microbiomes from a Full-Scale Woodchip Bioreactor Treating Agricultural Drainage Water

2021 ◽  
Vol 9 (6) ◽  
pp. 1331
Author(s):  
Arnaud Jéglot ◽  
Sebastian Reinhold Sørensen ◽  
Kirk M. Schnorr ◽  
Finn Plauborg ◽  
Lars Elsgaard
Keyword(s):  
Temperature Response ◽  
Microbial Transformation ◽  
Drainage Water ◽  
Microbial Populations ◽  
Agricultural Drainage ◽  
Bacterial Populations ◽  
Cold Temperatures ◽  
Cold Adapted ◽  
Agricultural Drainage Water ◽  
Temperature Responses

Denitrifying woodchip bioreactors (WBR), which aim to reduce nitrate (NO3−) pollution from agricultural drainage water, are less efficient when cold temperatures slow down the microbial transformation processes. Conducting bioaugmentation could potentially increase the NO3− removal efficiency during these specific periods. First, it is necessary to investigate denitrifying microbial populations in these facilities and understand their temperature responses. We hypothesized that seasonal changes and subsequent adaptations of microbial populations would allow for enrichment of cold-adapted denitrifying bacterial populations with potential use for bioaugmentation. Woodchip material was sampled from an operating WBR during spring, fall, and winter and used for enrichments of denitrifiers that were characterized by studies of metagenomics and temperature dependence of NO3− depletion. The successful enrichment of psychrotolerant denitrifiers was supported by the differences in temperature response, with the apparent domination of the phylum Proteobacteria and the genus Pseudomonas. The enrichments were found to have different microbiomes’ composition and they mainly differed with native woodchip microbiomes by a lower abundance of the genus Flavobacterium. Overall, the performance and composition of the enriched denitrifying population from the WBR microbiome indicated a potential for efficient NO3− removal at cold temperatures that could be stimulated by the addition of selected cold-adapted denitrifying bacteria.

Sign in / Sign up

Export Citation Format

Share Document