scholarly journals MICROBIAL ACTIVITY AND MYCORRHIZAL POTENTIAL OF FOUR OVERBURDEN TYPES USED IN THE RECLAMATION OF EXTRACTED OIL SANDS

1983 ◽  
Vol 63 (2) ◽  
pp. 363-375 ◽  
Author(s):  
R. M. DANIELSON ◽  
S. VISSER ◽  
D. PARKINSON
Keyword(s):  
Microbial Biomass ◽  
Microbial Activity ◽  
Plant Species ◽  
Oil Sands ◽  
Microbial Respiration ◽  
Bottom Layer ◽  
Jack Pine ◽  
Litter Bags ◽  
Mycorrhizal Development ◽  
Slender Wheatgrass

Slender wheatgrass and jack pine were grown in the greenhouse in cores containing a bottom layer of extracted oil sands with four overburdens individually layered over the sand. The overburdens included a muskeg peat, two shallow mineral overburdens and a deep overburden. Mycorrhizal development, microbial respiration and biomass and the degree of decomposition of slender wheatgrass roots in litter bags were determined in each plant species-overburden combination. Both ecto- and vesicular-arbuscular (VA) mycorrhizal inoculum was present in all four overburdens. The symbionts of slender wheatgrass were the "fine endophyte" and Glomus aggregatum. VA development was very low in peat whereas plants in the shallow overburdens became heavily mycorrhizal. Infection did not spread from the overburden layer to roots in the tailing sand. Jack pine roots in the peat and two shallow overburdens were heavily infected after 4 months. The most common symbiont was an ascomycete known as the E-strain. Microbial respiration was highest in the peat and was not influenced by plant species. Microbial biomass was also highest in the peat and much lower in the mineral overburdens. Only in the peat was the amount of microbial biomass larger with slender wheatgrass than with jack pine. Slender wheatgrass roots decomposed most rapidly in the peat overburden and least rapidly in the deep overburden. Key words: Microbial activity, jack pine, slender wheatgrass, mycorrhizae, reclamation, oil sands

scholarly journals Stoichiometry constrains microbial response to root exudation- insights from a model and a field experiment in a temperate forest

2013 ◽  
Vol 10 (2) ◽  
pp. 821-838 ◽  
Author(s):  
J. E. Drake ◽  
B. A. Darby ◽  
M.-A. Giasson ◽  
M. A. Kramer ◽  
R. P. Phillips ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Microbial Biomass ◽  
Field Experiment ◽  
Microbial Activity ◽  
Root Exudates ◽  
Microbial Respiration ◽  
Root Exudation ◽  
N Availability ◽  
Rhizosphere Soils ◽  
Wide Range

Abstract. Plant roots release a wide range of chemicals into soils. This process, termed root exudation, is thought to increase the activity of microbes and the exoenzymes they synthesize, leading to accelerated rates of carbon (C) mineralization and nutrient cycling in rhizosphere soils relative to bulk soils. The nitrogen (N) content of microbial biomass and exoenzymes may introduce a stoichiometric constraint on the ability of microbes to effectively utilize the root exudates, particularly if the exudates are rich in C but low in N. We combined a theoretical model of microbial activity with an exudation experiment to test the hypothesis that the ability of soil microbes to utilize root exudates for the synthesis of additional biomass and exoenzymes is constrained by N availability. The field experiment simulated exudation by automatically pumping solutions of chemicals often found in root exudates ("exudate mimics") containing C alone or C in combination with N (C : N ratio of 10) through microlysimeter "root simulators" into intact forest soils in two 50-day experiments. The delivery of C-only exudate mimics increased microbial respiration but had no effect on microbial biomass or exoenzyme activities. By contrast, experimental delivery of exudate mimics containing both C and N significantly increased microbial respiration, microbial biomass, and the activity of exoenzymes that decompose low molecular weight components of soil organic matter (SOM, e.g., cellulose, amino sugars), while decreasing the activity of exoenzymes that degrade high molecular weight SOM (e.g., polyphenols, lignin). The modeling results were consistent with the experiments; simulated delivery of C-only exudates induced microbial N-limitation, which constrained the synthesis of microbial biomass and exoenzymes. Exuding N as well as C alleviated this stoichiometric constraint in the model, allowing for increased exoenzyme production, the priming of decomposition, and a net release of N from SOM (i.e., mineralization). The quantity of N released from SOM in the model simulations was, under most circumstances, in excess of the N in the exudate pulse, suggesting that the exudation of N-containing compounds can be a viable strategy for plant-N acquisition via a priming effect. The experimental and modeling results were consistent with our hypothesis that N-containing compounds in root exudates affect rhizosphere processes by providing substrates for the synthesis of N-rich microbial biomass and exoenzymes. This study suggests that exudate stoichiometry is an important and underappreciated driver of microbial activity in rhizosphere soils.

Initial vesicular–arbuscular mycorrhizal development of slender wheatgrass on two amended mine spoils

1982 ◽  
Vol 60 (11) ◽  
pp. 2241-2248 ◽  
Author(s):  
J. C. Zak ◽  
D. Parkinson
Keyword(s):  
Sewage Sludge ◽  
Oil Sands ◽  
Arbuscular Mycorrhizal ◽  
Mycorrhizal Infection ◽  
Mine Spoils ◽  
Mycorrhizal Root ◽  
Vesicular Arbuscular ◽  
Plant Emergence ◽  
Mycorrhizal Development ◽  
Slender Wheatgrass

The initial vesicular–arbuscular (VA) mycorrhizal development of slender wheatgrass on extracted oil-sands and subalpine coal-mine spoils, amended with either fertilizer, peat, or liquid sewage sludge, was examined. Plants were sampled at 2, 6, and 10 weeks after plant emergence and the level of infection was expressed as length of mycorrhizal root per plant and length of root which contained arbuscules, vesicles, or only hyphae. Mycorrhizal infection of slender wheatgrass on the oil sands was limited to plants on the peat-amended spoil. Infection of plants on the peat-amended oil-sands spoil was detected by 2 weeks. Plants on the subalpine spoil were infected at 2 weeks only on the peat-amended spoil. While slender wheatgrass on the control and fertilizer-amended spoil developed mycorrhizae by 6 weeks, infection was not observed in plants on the sewage-amended spoil until 10 weeks. At 10 weeks, there were no significant differences in lengths of mycorrhizal root per plant among the amendments. Increased P levels in the fertilizer- and sewage-amended subalpine spoil did not suppress VA mycorrhizal development.

scholarly journals Responses of Soil Microbial Activity to Swine Manure Applications

2020 ◽  
Vol 12 (9) ◽  
pp. 199
Author(s):  
Maria Josiane Martins ◽  
Tânia Santos Silva ◽  
Igor Paranhos Caldas ◽  
Geovane Teixeira de Azevedo ◽  
Isabelle Carolyne Cardoso ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Microbial Activity ◽  
Microbial Respiration ◽  
Swine Manure ◽  
Soil Microbial Activity ◽  
Soil Microbial ◽  
Liquid Swine Manure ◽  
Randomized Design ◽  
Set Up ◽  
The Impact

The allocation of the large amount of swine waste from farms is an international concern. An efficient way of managing such waste is its use in farming. It is already known that the incorporation of organic waste into the soil significantly increases the microbial population. Therefore, the objective was to evaluate the impact of the use of swine manure on the soil microbiota in a Eutrophic Oxisol. The experiment was set up in a completely randomized design in a 6 × 4 factorial scheme (sixconcentrations of swine manure and four evaluation periods) with four replications. We evaluate the following characteristics: microbial respiration (C-CO2), microbial biomass (µC g-1 soil) and pH.: microbial respiration (C-CO2), microbial biomass (µC g-1 soil) and pH. A significant effect was found in the interaction between concentrations and time of incubation (p < 0.05) of swine manure on microbial activity in the soil. The amount of microbial carbon increased as a function of increased levels of liquid swine manure. No interaction was observed between concentrations and time of incubation for the pH. The evaluation of the isolated factors allowed to observe that the pH decreased as the doses of manure were incremented. Higher and lower pH values were found after 5 and 30 days of incubation. The application of liquid swine manure up to 6000 L ha-1 increases the release of CO2 and carbon in the microbial biomass. The applications of liquid swine manure cause a gradual reduction in soil pH.

scholarly journals Effect of Sheep Urine Deposition on the Bacterial Community Structure in an Acidic Upland Grassland Soil

2006 ◽  
Vol 72 (11) ◽  
pp. 7231-7237 ◽  
Author(s):  
Deirdre Rooney ◽  
Nabla Kennedy ◽  
Louise Deering ◽  
Deirdre Gleeson ◽  
Nicholas Clipson
Keyword(s):  
Community Structure ◽  
Microbial Biomass ◽  
Bacterial Community ◽  
Microbial Activity ◽  
Community Composition ◽  
Plant Species ◽  
Bacterial Community Structure ◽  
Bacterial Community Composition ◽  
High Concentrations ◽  
Sheep Urine

ABSTRACT The effect of the addition of synthetic sheep urine (SSU) and plant species on the bacterial community composition of upland acidic grasslands was studied using a microcosm approach. Low, medium, and high concentrations of SSU were applied to pots containing plant species typical of both unimproved (Agrostis capillaris) and agriculturally improved (Lolium perenne) grasslands, and harvests were carried out 10 days and 50 days after the addition of SSU. SSU application significantly increased both soil pH (P < 0.005), with pH values ranging from pH 5.4 (zero SSU) to pH 6.4 (high SSU), and microbial activity (P < 0.005), with treatment with medium and high levels of SSU displaying significantly higher microbial activity (triphenylformazan dehydrogenase activity) than treatment of soil with zero or low concentrations of SSU. Microbial biomass, however, was not significantly altered by any of the SSU applications. Plant species alone had no effect on microbial biomass or activity. Bacterial community structure was profiled using bacterial automated ribosomal intergenic spacer analysis. Multidimensional scaling plots indicated that applications of high concentrations of SSU significantly altered the bacterial community composition in the presence of plant species but at different times: 10 days after application of high concentrations of SSU, the bacterial community composition of L. perenne-planted soils differed significantly from those of any other soils, whereas in the case of A. capillaris-planted soils, the bacterial community composition was different 50 days after treatment with high concentrations of SSU. Canonical correspondence analysis also highlighted the importance of interactions between SSU addition, plant species, and time in the bacterial community structure. This study has shown that the response of plants and bacterial communities to sheep urine deposition in grasslands is dependent on both the grass species present and the concentration of SSU applied, which may have important ecological consequences for agricultural grasslands.

scholarly journals Stoichiometry constrains microbial response to root exudation – insights from a model and a field experiment in a temperate forest

2012 ◽  
Vol 9 (6) ◽  
pp. 6899-6945 ◽  
Author(s):  
J. E. Drake ◽  
B. A. Darby ◽  
M.-A. Giasson ◽  
M. A. Kramer ◽  
R. P. Phillips ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Microbial Biomass ◽  
Field Experiment ◽  
Microbial Activity ◽  
Microbial Respiration ◽  
Root Exudation ◽  
Rhizosphere Soils ◽  
Microbial Response ◽  
Wide Range ◽  
C And N

Abstract. Healthy plant roots release a wide range of chemicals into soils. This process, termed root exudation, is thought to increase the activity of microbes and the exo-enzymes they synthesize, leading to accelerated rates of carbon (C) mineralization and nutrient cycling in rhizosphere soils relative to bulk soils. The causal role of exudation, however, is difficult to isolate with in-situ observations, given the complex nature of the rhizosphere environment. We investigated the potential effects of root exudation on microbial and exo-enzyme activity using a theoretical model of decomposition and a field experiment, with a specific focus on the stoichiometric constraint of nitrogen (N) availability. The field experiment isolated the effect of exudation by pumping solutions of exudate mimics through microlysimeter "root simulators" into intact forest soils over two 50-day periods. Using a combined model-experiment approach, we tested two hypotheses: (1) exudation alone is sufficient to stimulate microbial and exo-enzyme activity in rhizosphere soils, and (2) microbial response to C-exudates (carbohydrates and organic acids) is constrained by N-limitation. Experimental delivery of exudate mimics containing C and N significantly increased microbial respiration, microbial biomass, and the activity of exo-enzymes that decompose labile components of soil organic matter (SOM, e.g., cellulose, amino sugars), while decreasing the activity of exo-enzymes that degrade recalcitrant SOM (e.g., polyphenols, lignin). However, delivery of C-only exudates had no effect on microbial biomass or overall exo-enzyme activity, and only increased microbial respiration. The theoretical decomposition model produced complementary results; the modeled microbial response to C-only exudates was constrained by limited N supply to support the synthesis of N-rich microbial biomass and exo-enzymes, while exuding C and N together elicited an increase in modeled microbial biomass, exo-enzyme activity, and decomposition. Thus, hypothesis (2) was supported, while hypothesis (1) was only supported when C and N compounds were exuded together. This study supports a cause-and-effect relationship between root exudation and enhanced microbial activity, and suggests that exudate stoichiometry is an important and underappreciated driver of microbial activity in rhizosphere soils.

Changes in microbial biomass and organic matter levels during the first year of modified tillage and stubble management practices on a red earth

Soil Research ◽  
1994 ◽  
Vol 32 (6) ◽  
pp. 1339 ◽  
Author(s):  
V Gupta ◽  
MM Roper ◽  
JA Kirkegaard ◽  
JF Angus
Keyword(s):  
Organic Matter ◽  
Microbial Biomass ◽  
Microbial Activity ◽  
Management Practices ◽  
Microbial Respiration ◽  
Microbial Biomass C ◽  
First Year ◽  
Tillage Practices ◽  
Red Earth

Farming practices involving stubble burning and excessive tillage in Australia have led to losses of organic matter from the soil. Crop residue retention and reduced tillage practices can reverse these trends, but changes in organic matter levels are evident only after a long term. Microbial biomass (MB), the living portion of soil organic matter, responds rapidly to changes in soil and crop management practices. We evaluated changes in microbial biomass and microbial activity in the first year following the modification of stubble management and tillage practices on a red earth near Harden, New South Wales. Following an oat crop harvested late in 1989, seven treatments involving stubble and tillage management were applied in February 1990. Wheat was planted in May 1990. Measurements of total organic carbon (C) and total nitrogen (N) in the top 15 cm of soil indicated no significant changes after 1 year, although there was a significant effect on the distribution of C and N. However, significant changes in MB were observed in the first year. Microbial biomass C in the top 5 cm of the soil ranged from 25 to 52 g C m-2 and these levels dropped by 50% or more with each 5 cm depth. Implementation of treatments altered MB, particularly in the top 5 cm where MB-C and MB-N were significantly greater in stubble-retained than in the top 5 cm where MB-C and MB-N were significantly greater in stubble-retained than in the stubble-burnt treatments, and in the direct drill treatment than in the stubble-incorporated treatment. Microbial biomass in soil increased during the growth of wheat in all treatments, but this was slower in the standing stubble-direct drill treatment, probably due to the delay in the decomposition of stubble. Microbial respiration, which was concentrated in the surface 5 cm of soil in all treatments, was greatest in the direct drill treatments. Microbial activity below 5 cm was higher with stubble incorporation than with direct drill. Specific microbial activity (microbial respiration per unit MB) had the greatest response to tillage at 10-15 cm depth. Microbial quotients (MB as a percentage of C or N) responded to changes in tillage but not significantly to stubble retention. Our studies, during the first year following the modification of stubble management and tillage practices, suggested that changes in MB and microbial activity may be sensitive and reliable indicators of long-term changes in organic matter in soils.

scholarly journals Rhizospheric activity of phytoremediation species in soil contaminated with picloram1

2017 ◽  
Vol 47 (2) ◽  
pp. 127-133 ◽  
Author(s):  
Wendel Magno de Souza ◽  
Fernanda Aparecida Rodrigues Guimarães ◽  
Matheus de Freitas Souza ◽  
Daniel Valadão Silva ◽  
Christiane Augusta Diniz Melo
Keyword(s):  
Zea Mays ◽  
Microbial Biomass ◽  
Microbial Activity ◽  
Plant Species ◽  
Microbial Biomass Carbon ◽  
Soil Microbial Activity ◽  
Metabolic Quotient ◽  
Panicum Maximum ◽  
Biomass Carbon ◽  
Urochloa Brizantha

ABSTRACT Some plant species have the ability to stimulate the microbiota activity in the rhizosphere and thereby increase the herbicide degradation in the soil. This study aimed at evaluating the microbial activity of soils contaminated with picloram and pre-cultivated with phytoremediation species. The experimental design was completely randomized, with three replicates. The treatments were organized in a 5 x 2 factorial scheme, with the first factor being the types of cultivation (autoclaved and non-autoclaved soil without cultivation and soil from the rhizosphere of Urochloa brizantha, Panicum maximum and Zea mays) and the second factor referring to the absence or presence (240 g ha-1) of picloram. The evolved C-CO2, microbial biomass carbon and metabolic quotient were estimated. The herbicide altered the evolved C-CO2, however, it did not affect the microbial biomass carbon and the metabolic quotient in the rhizospheric soils of the species. The cultivation of Zea mays increased the rhizosphere activity. The three plant species affect the soil microbial activity, however, the cultivation of Panicum maximum and Urochloa brizantha cause a lower disturbance on the microbial population, if compared to Zea mays. The picloran application does not affect the biological quality of the soils studied.

PLANT GROWTH IN FOUR OVERBURDEN TYPES USED IN THE RECLAMATION OF EXTRACTED OIL SANDS

1983 ◽  
Vol 63 (2) ◽  
pp. 353-361 ◽  
Author(s):  
R. M. DANIELSON ◽  
S. VISSER ◽  
D. PARKINSON
Keyword(s):  
Plant Growth ◽  
Oil Sands ◽  
Thick Layer ◽  
Jack Pine ◽  
Sand Layer ◽  
Oil Sand ◽  
Shoot Production ◽  
Deep Layers ◽  
Slender Wheatgrass ◽  
Northern Alberta

Two shallow mineral overburdens, a deep mineral overburden and a peat overburden from northern Alberta were examined to determine effects of each on the growth of jack pine and slender wheatgrass. Plants were grown in the greenhouse in 30-cm-deep cores in which the overburdens were placed in either 5- or 15-cm-deep layers over oil sand tailings. For comparison with current reclamation practices, cores containing a mixture of sand, peat and deep overburden were also used. The growth of slender wheatgrass was best in the peat and very poor in the deep overburden. Jack pine also grew very poorly in the deep overburden but reasonably well in the other three overburdens. There was extensive root development of both species in the sand layer beneath all four overburden types. Increasing the depth of peat from 5 to 15 cm resulted in a decrease in the growth of both plants whereas increasing the depth of the mineral overburdens had favorable effects. The amount of available P was much higher in sand under the 5-cm layers than sand under the 15-cm layers. Iron and Mn uptake was suppressed with the thick layer of peat. Mixing 15 cm of peat with deep overburden and sand did not affect the growth of slender wheatgrass but reduced shoot production of jack pine. Key words: Reclamation, oil sands, jack pine, slender wheatgrass, plant growth, peat

scholarly journals Ant nests as a microbial hot spots in a long-term heavy metal-contaminated soils

2021 ◽  
Author(s):  
Beata Klimek ◽  
Hanna Poliwka-Modliborek ◽  
Irena M. Grześ
Keyword(s):  
Microbial Biomass ◽  
Microbial Activity ◽  
Respiration Rate ◽  
Metal Content ◽  
Soil Microbial Activity ◽  
Bulk Soil ◽  
Lasius Niger ◽  
Soil Microbial ◽  
Ant Nests

AbstractInteractions between soil fauna and soil microorganisms are not fully recognized, especially in extreme environments, such as long-term metal-polluted soils. The purpose of the study was to assess how the presence of Lasius niger ants affected soil microbial characteristics in a long-term metal-polluted area (Upper Silesia in Poland). Paired soil samples were taken from bulk soil and from ant nests and analysed for a range of soil physicochemical properties, including metal content (zinc, cadmium, and lead). Microbial analysis included soil microbial activity (soil respiration rate), microbial biomass (substrate-induced respiration rate), and bacteria catabolic properties (Biolog® ECO plates). Soil collected from ant nests was drier and was characterized by a lower content of organic matter, carbon and nitrogen contents, and also lower metal content than bulk soil. Soil microbial respiration rate was positively related to soil pH (p = 0.01) and negatively to water-soluble metal content, integrated into TIws index (p = 0.01). Soil microbial biomass was negatively related to TIws index (p = 0.04). Neither soil microbial activity and biomass nor bacteria catabolic activity and diversity indices differed between bulk soil and ant nests. Taken together, ant activity reduced soil contamination by metals in a microscale which support microbial community activity and biomass but did not affect Biolog® culturable bacteria.

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