Nutrient Amendments Research Articles

Bioremediation Efficiency of Bacillus amyloliquefaciens and Pseudomonas aeruginosa with the Nutrient Amendment on Crude Oil Polluted the Soil

Aim: To assess the Bioremediation efficiency of Bacillus amyloliquefaciens and Pseudomonas aeruginosa strain CL 9 with nutrient amendment using bio-stimulating agents such as Fish waste and Goat manure on crude oil polluted soils in Rivers State, Nigeria.
 Study Design: The study employs experimental design, statistical analysis of the data and interpretation.
 Place and Duration of Study: A portion of Rivers State University demonstration farmland in Nkpolu-Oroworukwo, Mile 3 Diobu area of Port Harcourt, Rivers State was used for this study. The piece of land is situated at Longitude 4°48’18.50’’N and Latitude 6o58’39.12’’E measuring 5.4864 m x 5.1816 m with a total area of 28.4283 m2. Bioremediation monitoring lasted for 56 days, analysis carried out weekly (per 7 days interval).
 Methodology: Seven (7) experimental plots were employed using a Randomized Block Design each having dimensions of 100 x 50 x 20 cm (Length x Breadth x Height) were formed and mapped out on agricultural soil and left fallow for 6 days before contamination on the seventh day; after which it was allowed for 21 days for proper contamination and exposure to natural environmental factors to mimic crude oil spill site. Thereafter bio stimulating agents usually referred to as nutrient amendment organics in this study (fish waste and goat manure) and bio-augmenting microorganisms were applied. Soil profile before and after contamination was assayed while parameters like Nitrate, Sulphate, Phosphate, Total Organic Carbon (TOC) and Total Petroleum Hydrocarbon (TPH), were monitored throughout the experimental period. Microbial analyses such as Total Heterotrophic Bacteria (THB), Total Heterotrophic Fungi (THF), Hydrocarbon Utilizing Bacteria (HUB) and Hydrocarbon Utilizing Fungi (HUF) were recorded. Bioremediation efficiency was estimated from percentage (%) reduction of Total Petroleum Hydrocarbon (TPH) from day 1 to the residual hydrocarbon at day 56 of bio augmented/ biostimulation plots with the control.
 Results: Results revealed amount of remediated hydrocarbon and % Bioremediation efficiency at 56 days in the different treatment plots (initial TPH contamination value of 9296.83 mg/kg) in a decreasing order as follows: PS+Bac+Pse+GF+FW (8032.825 mg/kg; 86.40%) >PS+GF+FW (6867.825 mg/kg; 73.87%) >PS+Bac+Pse (6587.825mg/kg; 70.86%) >PS+FW (6441.825mg/kg; 69.29%) >PS+GF (5909.825 mg/kg; 63.57%) >CTRL 2 (Polluted soil without amendment) (3604.825mg/kg; 38.78%). Microbiological results showed increased colonial values with increase time exposure. The results observed on day 56 indicate that Polluted soil + Bacillus + Pseudomonas (10.11 Log10 CFU/g) > Polluted soil but un-amended soil (8.76 Log10 CFU/g) > unpolluted soil (8.68 Log10 CFU/g). Comparatively, Polluted soil +Bacillus + Pseudomonas expressed higher heterotrophic bacteria of 9.77 and 9.67 Log10 CFU/g while fungal counts recorded 6.04 and 6.82 Log10 CFU/g.
 Conclusion: Study showed that bioremediation of crude oil-polluted soils with bacteria singly is less effective but a combination with other organic nutrients is a better palliative measure. Therefore, amendment with organic nutrients like Goat manure and Fish wastes is recommended for crude oil polluted soils due to its high nutrient content as substrates for biostimulation of indigenous and augmenting biodegrading microbes. This process could be a source of enhanced natural attenuation of oil-contaminated environments in Nigeria.

Time-series analysis of phosphorus-depleted microbial communities in carbon/nitrogen-amended soils

The mineralization of organic phosphorus (P) in soil is mainly driven by extracellular phosphatases secreted by soil microbes. Previous studies have suggested that microbial phosphatase production is regulated by soil nutrient stoichiometry and, thus, promoted by carbon and nitrogen (CN) amendment. However, the mechanism leading to increased phosphatase activity after nutrient amendment to soil is unclear, and it is not known how long the effect of the nutrient amendment lasts. To address these questions, we performed a 24-day time-series analysis of full-factorial soil microcosms with CN amendment. Phosphatase activity as well as that expressed per unit of β-d-glucosidase activity, increased sharply and significantly in response to the CN amendment. This suggests that the microbial community shifted their resource allocation after the nutrient amendment and preferentially produced phosphatases rather than β-d-glucosidase. This shifted resource allocation pattern was maintained throughout the 24-day incubation period, and copiotrophic microbes dominated soils that received CN amendment. These results indicate that the effect of the CN amendment on soil microbial resource allocation lasted for >24 days. Together, our results highlight the importance of high-resolution time-series observations that complement long-term studies for which frequent observation is often difficult.

Soil enzyme activity and stoichiometry along a gradient of vegetation restoration at the Karst Critical Zone Observatory in Southwest China

AbstractThe “Grain for Green Programme” was implemented in the 1990s as a solution to the extreme degradation of karst landscapes that cover one‐third of China, largely caused by decades of poorly managed intensive agriculture. The recovery of soil functions is key to the success of ecosystem regeneration of abandoned croplands where the carbon (C) and nutrient cycles have been severely perturbed by cultivation. However, an ecological ‘tipping point’ beyond which soil functions are unrecoverable in manageable timescales may have been passed in the fragile, subtropical karst ecosystem. The aim of this study was to use the activity of key enzymes for C, nitrogen (N), and phosphorus (P) acquisition in the soil as a proxy for the biological response to vegetation restoration after agricultural abandonment in a severely degraded karst catchment at the Karst Critical Zone Observatory in Guizhou Province. In 2016, a space‐for‐time approach was used to establish a chronosequence of vegetation recovery: sloping cropland < recently abandoned sloping cropland < shrubland < secondary (regenerated) forest < primary (natural) forest. Soils were sampled from the surface to the bedrock (up to 80‐cm depth) in each recovery phase. The activity of all enzymes in the top 0 to 30‐cm depth increased after abandonment and was positively correlated with soil nutrient and water contents. Nitrogen deficiencies were indicated by the reduced ratios of C‐ relative to N‐hydrolase activity and the increased ratios of N‐ relative to P‐hydrolase activity in the abandoned croplands and shrublands. Phosphorus deficiencies were indicated by the reduced ratios of N‐ relative to P‐hydrolase activity and C‐ relative to P‐hydrolase activity in the soils of the shrubland and secondary forest compared with the primary forest. Our results revealed that near‐to‐natural biological soil function was recoverable as vegetation naturally restored and suggested that the rate of recovery may be accelerated by managed nutrient amendments during the early stages after abandonment. This new information may help to inform the managed regeneration of degraded agricultural land in nutrient‐poor, subtropical environments.

Variation in rhizosphere microbiota correlates with edaphic factor in an abandoned antimony tailing dump

The distribution pattern of root-associated bacteria in native plant growth in tailing dumps with extreme conditions remains poorly understood and largely unexplored. Herein we chose a native plant, Bidens bipinnata, growing on both an Sb tailing dump (WKA) and adjacent normal soils (WKC) to in-depth understand the distribution pattern of root-associated bacteria and their responses on environmental factors. We found that the rhizosphere microbial diversity indices in the tailing dump were significantly different from that in the adjacent soil, and that such variation was significantly related with soil nutrients (TC, TOC, TN) and metal(loid) concentrations (Sb and As). Some dominant genera were significant enriched in WKA, suggesting their adaption to harsh environments. Notably, these genera are proposed to be involved in nutrient and metal(liod) cycling, such as nitrogen fixing (Devosia, Cellvibrio, Lysobacter, and Cohnella), P solubilizing (Flavobacterium), and Sb and As oxidation (Paenibacillus, Bacillus, Pseudomonas, and Thiobacillus). Our results suggest that certain root-associated bacteria in tailing dump were governed by soil edaphic factors and play important ecological roles in nutrient amendments and metal cycling for the successful colonization of Bidens bipinnata in this tailing dump.

Comparing Bioremediation Approaches for Agricultural Soil Affected with Petroleum Crude: A Case Study.

The aim of work was to check and make comparison of efficacy for five approaches for petroleum crude contaminated agricultural soil remediation by making use of soil microcosms. Concerning the published literature in our information, this is the first report comparing five approaches i.e. abiotic losses, native microbial flora, nutrient amendments and pre-adapted native microbial culture and concurrent amendments of nutrients + pre-adapted native microbial culture for agricultural soil bioremediation using Pseudomonas aeruginosa NCIM 5514 by performing soil microcosm experiments. 96.00 ± 0.18% degradation of petroleum hydrocarbon fractions in 60days of the experiment was observed when nutrients and P. aeruginosa NCIM 5514 were applied concomitantly. In nutrients- and P. aeruginosa NCIM 5514-added microcosm reduction in nitrogen, organic carbon, and phosphorus was noted. P. aeruginosa NCIM 5514, can be applied as a prospective bioremediation agent to remediate petroleum crude contaminated soil.

Evaluation of the Methane Production Potential of Catfish Processing Wastewater Using Various Anaerobic Digestion Strategies

The U.S. catfish industry is a major industry that has been declining over the years due to imports competition and growing operational costs. Catfish processing wastewater management and high energy requirement put a large financial burden on catfish processing facilities. Recovered protein-based solids have provided some value-added co-products, however, more co-products are needed to offset processing costs. Anaerobic digestion is a proven waste treatment method that produces methane, which is an energetic co-product that can be used within the processing facilities. This study was conducted to evaluate the potential of anaerobic digestion as an alternative to the currently used aerobic biotreatment of catfish processing wastewater. Initial assessments indicated the recalcitrance of the full-strength wastewater to anaerobic digestion, yielding only ~4 m3 per ton (U.S.) of input chemical oxygen demand (CODinput). Thus, several strategies were evaluated to improve the methane yield from the wastewater. These strategies include nutrient (nitrogen and sulfur) amendment, along with ozone, HCl, and NaOH pretreatment. The results showed that nutrient amendment was the most suitable strategy for improving the digestibility of the catfish processing wastewater. A methane yield of 121–236 m3/ton (U.S.) CODinput was obtained, with a purity of 67–80 vol.%. These results are similar to yields and purities of biogas from other feedstock, such as food waste, wastewater solids, and fish canning wastewater. This indicates that anaerobic digestion could be a viable alternative for simultaneous treatment and energetic co-product generation from catfish processing wastewater.

Influence of abiotic factors, natural attenuation, bioaugmentation and nutrient supplementation on bioremediation of petroleum crude contaminated agricultural soil

Contamination of agricultural land(s) is a major problem worldwide which is associated with activities of petroleum industry. Due to these exploration activities remedial techniques for clean-up of contaminated agricultural soil(s) has become an alarming research topic. Hydrocarbon utilizing bacterial consortium (HUBC), isolated from petroleum crude (petroleum industry waste water and soil) contaminated sites, India has been used for soil microcosm study. The aim of present study was to compare potency of five different techniques to remediate petroleum hydrocarbons contaminated agricultural soil by employing soil microcosm study. To the best of our knowledge this is the first report for comparison of five different techniques (abiotic control, natural attenuation, biostimulation, bioaugmentation and simultaneous bioaugmentation & biostimulation) for bioremediation of agricultural soil using consortium of hydrocarbon utilizers by employing soil microcosms. Concurrent application of bioaugmentation (with HUBC) and biostimulation (with nutrient amendments) in the soil microcosm resulted in 93.67 ± 1.80% hydrocarbons degradation in 45 days of experiment and hydrocarbon utilizing bacterial count was recorded 4.11 ± 0.11 × 108 CFU/g. In the bioaugmented and biostimulated soil microcosm organic carbon was reduced from 3.49 ± 0.08% to 0.62 ± 0.11% with simultaneous decrease of other nutrients. The consortium could survive in artificially crude oil contaminated and nutrients amended agricultural soil microcosm and could degrade petroleum hydrocarbons effectively in soil microcosm conditions. This suggests its application as a potential bioremediation agent for farmland restoration i.e. management of soil environment.

Post Bioremediation Effect on Soil Fertility using Substrate from Livestock Byproduct

The purpose of this study was to examine data obtained from soil physicochemical properties before and after initiation of bioremediation using liquid manure as a nutrient source. Bioremediation was initiated by stimulating autochthonous microorganisms present in soil rhizosphere while remediation was determined by soil physicochemical status after nutrient amendment. Rhizomes of turmeric were planted in soil treated with liquid manure and control in a randomized complete block design (RCBD) with three replications. Data generated from soil physicochemical parameters both in the laboratory and field were analyzed before and after treatment/cultivation. The study showed that treated soil increased total nitrogen, organic matter, organic carbon, exchangeable potassium, cation exchange capacity (CEC), calcium and exchangeable phosphorus. On the other hand, it decreased soil acidity, pH and exchangeable aluminium. There were no observable differences in magnesium concentration. Soil texture had more sand and a corresponding decline in silt and clay. Findings in this study revealed that soil that benefitted from treatment option is statistically significant at 0.05 p-level.

Amendment of Soil Water Retention and Nutrients Holding Capacity by Using Sugar Cane Bagasse

Sugarcane bagasse (SCB)is byproduct of sugarcane industry can be used as soil amendments to improve soil hydro, physical-chemical characteristics. It also provides reasonable economic means to recycle these in an environmentally friendly manner. The soil samples were studied for different soil characteristics collected from different sites of Dodoma city, Tanzania. Soil sample with poor water holding capacity selected and made into six treatments by different percentages of sugarcane bagasse 0, 2, 5, 10,20 and 100% in triplicates for each treatment. The result showed that the water holding capacity of the soil increased from 26.85 to 84.08 % representing 3.16 times.The soil of Dodoma have low organic matter (438.6 - 1126.6 mg/kg), and deficient in K+ (0.5 cmol/kg), Ca2+ (2.8 cmol/kg), Mg2+ (1.3 mg /kg), Na+ (1.03 cmol/kg) and cation exchange capacity (5 cmol/kg). The available K+, Ca2+, Mg2+ contents of soil increased by 13.87, 22.79, 33.13 and 43.61% with the application of 2, 5, 10 and 20 % of sugarcane bagasse, respectively. Different levels of SCB positively influence the hydro, physico-chemical properties of soil. Utilization of SCB as organic fertilizer was found to save the water cost and chemical fertilizer along with minimizing environmental pollution. Application of 10% of sugarcane bagasse was found to be the standard dose to achieve important hydo, physicochemical properties of soil to a required level.

Bioremediation of arable soil using Nitrogen, Phosphorus, Potassium fertilizer treatment

This study seeks to examine “in situ” remediation effectiveness of NPK fertilizer treatment as a viable biostimulation-based bioremediation technology for soil remediation by evaluating data obtained from soil physicochemical properties before and after initiation of bioremediation. Bioremediation was initiated by stimulating indigenous microorganisms in soil by NPK application while remediation was determined by soil physicochemical condition after nutrient amendment and changes observed in plant height after 60, 90, 120, 150, 180 and 210 days of planting. Rhizomes of turmeric were planted in soil treated with NPK fertilizer and control in a randomized complete block design (RCBD) with three replications. Data generated from soil physicochemical parameters in laboratory and field was analyzed before and after treatment. Study showed increase in available potassium, available phosphorus, total nitrogen, pH, cation exchange capacity (CEC) and organic carbon. However, there was decrease in aluminium, soil organic matter and acidity. Sand, silt and clay also decreased slightly. Study revealed significant increase in plant height from plants that benefitted from nutrient amendment.

Bacterial Community Composition and Diversity Respond to Nutrient Amendment but Not Warming in a Maritime Antarctic Soil.

A resumption of climate warming in maritime Antarctica, arising from continued greenhouse gas emissions to the atmosphere, is predicted to lead to further expansions of plant populations across the region, with consequent increases in nutrient inputs to soils. Here, we test the main and interactive effects of warming, applied with open top chambers (OTCs), and nutrient amendment with tryptic soy broth (TSB), an artificial growth substrate, on bacterial community composition and diversity using Illumina sequencing of 16S rRNA genes in soil from a field experiment in the southern maritime Antarctic. Substantial effects of TSB application on bacterial communities were identified after 49months, including reduced diversity, altered phylogenetic community assembly processes, increased Proteobacteria-to-Acidobacteria ratios and significant divergence in community composition, notably increases in the relative abundances of the gram-positive genera Arthrobacter, Paeniglutamicibacter and Planococcus. Contrary to previous observations from other maritime Antarctic field warming experiments, we recorded no effects of warming with OTCs, or interactive effects of OTCs and TSB application, on bacterial community composition or diversity. Based on these findings, we conclude that further warming of the maritime Antarctic is unlikely to influence soil bacterial community composition or diversity directly, but that increased nutrient inputs arising from enhanced plant growth across the region may affect the composition of soil bacterial communities, with possible effects on ecosystem productivity.

Changes in soil macropores: Superposition of the roles of organic nutrient amendments and the greenhouse pattern in vegetable plantations

AbstractOrganic farming can potentially mitigate soil compaction, which commonly occurs in vegetable plantations, particularly in greenhouses when compared with open‐air systems. Although several studies have addressed the effect of planting patterns on soil pore characteristics, few studies have focused on changes in pore attributes under organic fertilization. We used adjacent fields during green manure planting as a control to compare the differences in soil physicochemical and macropore parameters between 14‐year‐old greenhouse plots and open‐air plots under organic fertilization. Pearson's correlation analysis was performed to analyse the drivers of soil macropore characteristics in vegetable plantations in Jiangsu Province, China. A significant increase in connectivity, fractal dimensions and total macroporosity and a decrease in bulk density after 14 years of organic farming, particularly in the surface layer in the greenhouse, were observed. However, the difference in pores in the plough pan layer was not significant between the treatments. The volume of small pores (50–500 μm) and medium pores (500–1,000 μm) increased significantly (p < 0.05) in both the greenhouse and open‐air systems, showing significantly positive relationships with soil organic matter (SOM) and total nitrogen (TN) content. Large pores (>1,000 μm) showed a clear decrease, especially in open‐air fields, possibly due to the disappearance of the original straw residues in the surface layer. Small and medium pores in the plough layer increased in greenhouse fields, whereas the opposite occurred in open‐air fields. Overall, compared with open‐air systems, long‐term organic greenhouse patterns had a significantly positive effect on soil pore attributes.

Inter & Active Effect of Tillage and Nitrogen Fertilizer on Maize (Zea mays L.) Performance on a Humid Alfisol Southwestern, Nigeria

A field trial was conducted in 2017 to investigate the interactive effect of the land preparation methods and different rates of nitrogenous fertilizer on maize performance and yield southwestern Nigeria. The experiment was a 3 by 3 factorial; conducted in a Randomized Complete Block Design (RCBD) in a split plot management with tillage systems (T): Convectional tillage (CT), Reduced tillage (RT) and No-tillage (NT) as the main plot while nutrient amendments (N) rates (0, 50, and 120 Kg N.Ha-1) as sub-plots factor and all treatments were replicated three times. Growth and yield parameters were subjected to analysis of variance (ANOVA). No tillage had the least plant height, stem diameter and stover weight but had the highest grains yield. Grain yield were not statistically different in all the tillage practices at different N rates applied but 60 kg N ha-1 seems best for maize production in the study area.

Bio-char influenced indigenous microbial stimulation for oil contaminated soil remediation in Northwest China

This research uses Illumina high-throughput sequencing method showing that Proteobacteria, Actinobacteria, and Fimicutes were the most influential phyla in the biodegradation process, Firmicutes and Deinococcus-Thermus were positively affected by the changes of nutrient amendments. Firmicutes can be seen as an indicator of degradation rate. Dietzia and Halomonas were the most dominant genus in Biochar and Blank degradation processes for oilfield contaminated soil in Northwest China.

Management strategies differentially affect root functional trait expression in cocoa agroforestry systems

In tree-based agroecosystems, environmental heterogeneity can be high and resource acquisition strategies among individual plants can be expected to vary. This poses a challenge for appropriate nutrient prescriptions. We used a novel trait-based approach to measure in situ fine root phenotypic response of cocoa (Theobroma cacao) to fertilization. Two levels of NPK fertilizer were applied to cocoa in agroforestry, with shade trees Entandrophragma angolense or Terminalia ivorensis, or in monoculture. Four months following fertilization, cocoa fine roots were extracted from ingrowth cores and analyzed for a suite of traits positively associated with resource acquisition: fine root production, ratio of absorptive to transport roots, specific root length, specific root area, specific root tip abundance, and root nitrogen content, as well as traits positively associated with longer-lived root organs (resource conservative): root tissue density, average root diameter, and root carbon to nitrogen ratio. In surface soils (0 to 10 cm), fertilization largely stimulated roots to express resource conservative strategies compared to unfertilized cocoa roots (up to 70% mean percent difference among all root traits) but with limited measurable differences in root trait response between the two fertilization levels. In subsurface soils (10 to 20 cm), however, inconsistent cocoa root responses to fertilization and shade trees suggested increasing complexity in nutrient acquisition strategies with soil depth. At both depths, we detected coordination among cocoa root trait variation including a resource acquisition to conservation axis explaining ~ 45% of total trait variation, yet an individual cocoa plant’s position on these coordinated trait axes was predominately affected by the shade tree rather than fertilization level. This study provides some of the first insights into intraspecific root functional trait expression to fertilization in multispecies agriculture. We show that a trait-based approach can be used to improve diagnostics and prescriptions of nutrient amendments in agroforestry systems.

Biochar Influenced Microbial Community Succession and Metabolic Characteristic During the Dropping Crude Remediation

This study determined the fluctuations of bacterial community structures in biochar biostimulation process with different types of nutrient amendments. Results showed that suitable amendment ratio of biochar and nutrients can greatly increase the remediation efficiency, biocharaddition influenced microbial community structure and metabolic characteristics of the remediation. Proteobacteria, Actinobacteria, and Fimicutes were the dominant phyla throughout the process, and biochar addition significantly increased the relative abundance of Firmicutes phylum. The detected abundance of bacterial genes related were also different, Amino acid transport and metabolism, Carbohydrate transport and metabolism were increased with biochar addition and had great influence on the bacterial community structure. These results indicated that biochar addition improved the degradation process meanwhile significantly regulated the microbial community and function.

Rhamnolipid-enhanced solubilization and biodegradation of PAHs in soils after conventional bioremediation

The application of a rhamnolipid biosurfactant for enhanced solubilization and biodegradation of slowly desorbing polycyclic aromatic hydrocarbons (PAHs) in contaminated soils was determined in this study. The soil samples exhibited different levels of pollution and different bioremediation stages: the first soil originated from a creosote-polluted site, contained 4370 mg kg −1 of PAHs and had not been bioremediated; the second soil was the same as the first but had received bioremediation treatment with nutrient amendment in biopiles for a period of 5 months and contained 580 mg kg −1 of PAHs after this treatment; the third soil was treated by bioremediation for several years to reduce the concentration of PAHs to 275 mg kg −1. The kinetics of PAH desorption were determined to assess the magnitude of the slowly desorbing fractions present in the polluted soil and to optimize the biosurfactant effectiveness in terms of biodegradation. The soils that had been treated by bioremediation were enriched in slowly desorbing PAHs. The rhamnolipid at a concentration above its critical micelle concentration enhanced biodegradation in the soils that had been bioremediated previously. The measurement of residual concentrations of native PAHs showed the promoting effect of the biosurfactant on the biodegradation of the slowly desorbing fractions. Interestingly, benzo(a)pyrene was biodegraded in the soil that had been bioremediated for a long time. Rhamnolipid can constitute a valid alternative to chemical surfactants in promoting the biodegradation of slow-desorption PAHs, which is one of the most important problems in bioremediation, but the efficiency depends strongly on the bioremediation stage in which the biosurfactant is applied.

Prospects of Stenotrophomonas pavanii DB1 in diesel utilization and reduction of its phytotoxicity on Vigna radiata

Diesel, for its carcinogenic and teratogenic properties, is considered as an environmental hazard. The present study concentrates on diesel utilization by Stenotrophomonas pavanii DB1 under various physicochemical parameters and mass spectral analysis of the metabolites produced. Soil remediation potential of the culture for reducing diesel toxicity against Vigna radiata seed germination was also evaluated. Supplementation of the broth with ammonium sulfate, molasses and tween 80 enhanced diesel utilization (up to 66.3%). A steady decrease in diesel utilization (69.46–51.23%) was recorded with the increase in salinity from 1 to 5000 mM. Similarly, the utilization efficiency was low (up to 11.5%) when cadmium, lead and mercury salts were present but was not affected by zinc and copper salts. Liquid chromatography–mass spectrometry revealed extensive utilization (95–99%) of both the short- (C10–C20) and long-chain (C18–C30) n-alkanes. Significantly, the culture exhibited uniform utilization of various recalcitrant n-alkanes, to generate metabolites like aldehyde, ketone, fatty acids, carboxylic and dicarboxylic acids. Stenotrophomonas pavanii DB1 mediated 95% and 86% of diesel utilization in soil with and without nutrient amendment, respectively. Germination percentage of V. radiata seeds improved with the bacterial inoculation of the diesel-containing soil. Stenotrophomonas pavanii DB1 culture did not establish antagonistic effect over the resident soil bacteria. Based on the spectral analysis and soil remediation studies, it could be inferred that S. pavanii DB1 is a potential culture for bioremediation of sites polluted with diesel.

Phragmites stimulation and natural attenuation of indigenous microbial community accelerated bioremediation of oil contaminated soil

Illumina high-throughput sequencing method was used to reflect fluctuation of indigenous microbial community during phragmites stimulation process in this study. Results showed Proteobacteria, Fimicutes, and Actinobacteria were most influential in process, Firmicutes and Deinococcus-Thermus were positively affected by nutrient amendment. Firmicutes can be seen as indicator of degradation rate. Dietzia, Salinimicrobium, and Halomonas were the most dominant genus in both Phragmites and Blank setups. These results indicated phragmites addition improved the efficiency of biodegradation and significantly regulated the microbial community structure and functions during remediation process.

Nutrient Source and Tillage Effects on Maize: I. Micrometeorological Methods for Measuring Carbon Dioxide Emissions

Core Ideas Aerodynamic methods can be used to gap‐fill Bowen ratio energy balance micrometeorological measurements. Eddy covariance and Bowen ratio energy balance methods agree during turbulent daytime conditions. Measuring nighttime net ecosystem exchange is challenging using turbulence‐based micrometeorology. There is a need to understand the potential benefits of using the biotechnology waste by‐product from manufacturing as a fertilizer replacement in agriculture, by quantifying the economic value for the farmer and measuring the environmental impact. Measuring CO2 emissions can be used to assess environmental impact, including three widely used micrometeorological methodologies: (i) the Bowen Ratio Energy Balance (BREB), (ii) aerodynamic flux‐gradient theory, and (iii) eddy covariance (EC). As a first step in quantifying benefits of applying biotechnology waste in agriculture, a detailed examination of these three methods was conducted to understand their effectiveness in quantifying CO2 emissions for this specific circumstance. The study measured micrometeorological properties over a field planted to maize (Zea mays L. var. indentata), one plot treated with biotechnology waste applied as a nutrient amendment, and one plot treated with a typical farmer fertilizer practice. Carbon dioxide flux measurements took place over 1 yr, using both BREB and EC systems. The aerodynamic method was used to gap‐fill BREB system measurements, and those flux estimates were compared with estimates produced separately by the aerodynamic and EC methods. All methods found greater emissions over the biotechnology waste application. The aerodynamic method CO2 flux estimates were considerably greater than both the EC and a combined BREB‐aerodynamic approach. During the day, the EC and BREB methods agree. At night, the aerodynamic approach detects and accounts for buildup of CO2 at the surface during stable periods. The BREB systems combined with aerodynamic approaches provide alternate methods to EC in examining micrometeorological properties near the surface.