The adsorption of Acid Violet 17 (AV17) was carried out using various activated carbons prepared from sunflower seed hull (SSH), an agricultural solid waste by-product. The effect of parameters such ...as agitation time, initial dye concentration, adsorbent dosage, pH and temperature were studied. The Langmuir and Freundlich isotherm models were applied and the Langmuir model was found to best report the equilibrium isotherm data. Langmuir adsorption capacity was found to be 116.27
mg/g. Kinetic data followed pseudo-second-order kinetics. Maximum colour removal was observed at pH 2.0. It was observed that the rate of adsorption improves with increasing temperature and the process is endothermic. The adsorbent surface was analysed with a scanning electron microscope. The results indicate that activated sunflower seed hull could be an attractive option for colour removal from dilute industrial effluents.
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•The magnetic nanocomposite (Fe3O4@ZIF-67) possesses excellent peroxidase mimic activity.•The magnetic nanocomposite is good catalytic activity in presence of H2O2.•Colorimetric ...sensor is highly sensitive and selective detection of Hg2+ ions.•The proposed sensing strategy is successfully applied for real sample analysis.
An extremely sensitive colorimetric sensor has been developed for selective determination of Hg2+ in aqueous solution based on magnetic nanocomposite (Fe3O4@ZIF-67), which results in an effective intrinsic peroxidase mimicking activities and makes the composites oxidize the 3, 3′, 5, 5′- tetramethyl benzidine (TMB) in the presence of hydrogen peroxide (H2O2) to produce a blue coloured solution. Significantly, the oxidation of TMB was retarded or prevented in the presence of antiradical biomolecules Glutathione (GSH) because of its strong cation restoration property. When Hg2+ is added, the strong affinity of mercury ions with thiol groups of GSH provokes the oxidation of the substrates, which helps the solution turn into blue colour. The absorbance intensity was proportional to the concentration of Hg2+ in the wide range of 0–30 nM and detection limit was successfully as low as 0.36 nM. The resultant nanocomposite based peroxidase mimicking activity applied as a versatile platform in the colorimetric detection of Hg2+ was established the other co-existing metal ions in aqueous solutions. Finally the sensor was applied to detect Hg2+ in real water sample with satisfactory recovery results. Interestingly, the proposed colorimetric sensing platform held great potential in the application of mercury contamination in industrial sewage.
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•Submergence stress can affect physiological and agronomic behavior.•Physiological and molecular mechanisms are discussed.•Management practices could promote resilience to submergence ...stress.•Genetic approaches should be the primary focus for mitigating submergence stress.
Rice is a crop of primary importance in regions, where two-thirds of the world’s starving population reside. Recent climate change projections anticipate spatial shift in precipitation pattern and increase of flooding events that may have negative effects on rice yield and economic returns. Efforts for increasing rice production in areas prone to submergence stress will directly benefit hundreds of millions of people dependent on rice as their staple food. This necessitates an objective review of physiological mechanisms and management practices, which could sustain crop productivity under partial or complete submergence. Submergence usually reduces photosynthesis rate that results in quick depletion of the carbohydrate reserve and ultimately the plant dies. Varieties introgressed with SUB1A QTL maintains higher activity of alcohol dehydrogenase and low rate of chlorophyll degradation and thus exhibits better survival under submergence. Prolonged submergence results in a significant reduction in soil redox potential and the heavy influx of flood water promotes runoff, volatilization and deep percolation which leads to loss of sizeable amount of nutrients and ultimately causes nutrient deficiency in soil. Thus, to ensure optimum yield, it is essential to alter the nutrient schedule when plant is subjected to submergence stress. Agronomic management practices like seed priming, higher seed rates, alteration in crop geometry and other improved seeding methods enhance production efficiency by boosting germination, early growth and optimum partitioning of photosynthates to vegetative and reproductive parts. This review critically explores the complex problems faced by rice crop during submergence, physiological mechanisms that helps plant to cope up the submergence stress, as well as available cost-effective management strategies to arrest the yield decline.
Phosphate-solubilizing microbes (PSM) are widely distributed in the rhizosphere and helps plant to acquire phosphates from soil. The availability of phosphates in soil are governed by several factors ...among which the proton exchange capacity has been regarded to be the most important factor involved in cation complex formations with soluble phosphates making them unavailable to plants, thereby disturbing the phosphorus cycling events found in arable soils. PSM solubilizes the cation complexes and thereby improves the functioning of phosphorus cycle in soil. In addition to involvement in biogeochemical cycling events, PSM have been also found to have antagonistic potential against several plant phytopathogens. These biocontrol microbes represent the most abundant groups of soil microflora. Among which some nutrient solubilizers have been used for effective biocontrol of important plant diseases. This review article shows contributions of different plant growth promoters used in nutrient and disease management practices in agriculture.
Abbreviations: P (phosphorus), PSM (phosphate-solubilizing microbes), PSB (phosphate-solubilizing bacteria), PSF (phosphate-solubilizing fungi), PGPM (plant growth-promoting microbes), PGPB (plant growth-promoting bacteria), SAR (systemic acquired resistance), ISR (induced systemic resistance), TCP (tri-calcium phosphate), HCN (hydrogen cyanide), IAA (indole-3-acetic acid),
a
Phosphorus (SSP) single super phosphate, RP (rock phosphate), PM (poultry manure) and FYM (farm yard manure), PAL (phenylalanine ammonia lyase), ESI-MS (electrospray ionization mass spectrometry), DAPG (2,4-diacetylphloroglucinol) and NMR (
1
H nuclear magnetic resonance).
Soil samples collected from different fruit orchards of Karnataka were used for isolation of Streptomyces spp. and all the isolates were screened for their plant growth-promoting (PGP) traits ...including phytohormones production viz. indole-3-acetic acid (IAA) and gibberellic acid (GA3), nutrient (phosphate and zinc) solubilisation, siderophore production, enzyme activities (cellulase, tannase and xylanase) and antagonistic potential against soil borne fungal pathogens. Based on PGP traits as well as compatibilities, the following three Streptomyces spp. ‘S. avermitillis PAN Act2 (NAIMCC-B-01412), S. cinnamonesis PAN Act3 (NAIMCC-B-01413) and S. canus PAN Act5 (NAIMCC-B-01342)’ were selected for Streptomyces consortium (SMC) preparation using lignite as carrier material. Out of three isolates, S. canus registered significantly higher IAA and GA3 production compared to other isolates. All three isolates had the potential to suppress the fungal phytopathogens viz. Cerotocystis fimbriata, Fusarium oxysporum, Macrophomina sp. and Sclerotium sp., with the levels of suppression ranging from 58.0% to 85.0%. The carrier-based SMC was subsequently evaluated in pomegranate to recover the plants from wilt like symptoms under field conditions. From this study, it was found that application of 50 gm of the SMC per plant through soil drenching at regular intervals (once every 2 months) had a significant impact on the recovery of the plant from wilt like symptoms after eight months. The present study is an addition to the growing knowledge on the utility of Streptomyces in fruit production.
Uses and management of poultry litter BOLAN, N.S.; SZOGI, A.A.; CHUASAVATHI, T. ...
World's poultry science journal,
12/2010, Letnik:
66, Številka:
4
Journal Article
Recenzirano
Odprti dostop
The poultry industry is one of the largest and fastest growing agro-based industries in the world. This can be attributed to an increasing demand for poultry meat and egg products. However, a major ...problem facing the poultry industry is the large-scale accumulation of wastes including manure and litter which may pose disposal and pollution problems unless environmentally and economically sustainable management technologies are evolved. Most of the litter produced by the poultry industry is currently applied to agricultural land as a source of nutrients and soil amendment. However environmental pollution, resulting from nutrient and contaminant leaching can occur when poultry litter is applied under soil and climatic conditions that do not favour agronomic utilisation of the manure-borne nutrients. This review examines the composition of poultry litter in relation to nutrient content and environmental contaminants, its value as a nutrient source, soil amendment, animal feed and fuel source, and cost-effective innovative technologies for improving its value. Poultry litter provides a major source of nitrogen, phosphorus and trace elements for crop production and is effective in improving physical and biological fertility, indicating that land application remains as the main option for the utilisation of this valuable resource. The alternative use of poultry litter; as an animal feed and fuel source, is limited by contaminants, and high moisture content, respectively. The review proposes best management practices to mitigate environmental consequences associated with air and water quality parameters that are impacted by land application in order to maintain the continued productivity, profitability, and sustainability of the poultry industry.
Application of pesticide in agricultural fields is “unnecessary evil” for non-target microflora and fauna. Hence, to identify the safer pesticide molecules against non-target microbes, a long-term ...pesticide experiment was initiated at National Rice Research Institute, Cuttack, India. In the present study, the effect of continuous application of chlorpyrifos (0.5kgha−1) in rice fields on non-target groups of soil microbes and nematodes was studied for seven seasons (four wet and three dry seasons) during 2009–2013. Treatments were arranged in a randomized complete block design with four replications of chlorpyrifos-treated (0.5kg a.i. ha−1) (CT) and untreated control (UT) plots. During seven seasons of experimentation, regular application of chlorpyrifos had no significant effect on population of heterotrophic aerobic, anaerobic, oligotrophic and copiotrophic bacteria in CT compared to UT, whereas, population of asymbiotic aerobic nitrogen fixer, nitrifiers, denitrifiers, gram positive and spore-forming bacteria were significantly reduced by nearly 0.25–2 fold in CT than UT. However, comparatively less deviation in population of actinomycetes, fungi, phosphate solubilizing and sulfur oxidizing bacteria were observed in CT than UT. Significant interactions were found between effects of chlorpyrifos with time in population dynamics of microbes. In plant parasitic nematode species, Meloidogyne graminicola (RRKN) and Hirschmanniella spp. (RRN), were significantly lower (p<0.01) in CT compared to UT after first year onwards. The overall observation of five years data indicated that the RRKN population showed a decreasing trend (R2=0.644) whereas RRN showed increasing trend (R2=0.932) in CT. The drastic chlorpyrifos dissipation was noticed after 15 days of application from the initial residue of 0.25mgkg−1 soil, which indicated that chlorpyrifos residue in rice field soil was not persistent and its half-life was found to be 4.02 days. Overall, the present findings revealed that non-target effect of repetitive application of chloropyrifos (0.5kgha−1) on soil microbes and nematodes was found less under rice-rice cropping system.
•Continuous application of chlorpyrifos on soil microbes and nematodes were studied.•Chlorpyrifos at field dose to rice soil was not harmful to most of the soil microbes.•Nitrogen mineralization microbial groups were most sensitive to chlorpyrifos.•Plant-parasitic nematodes showed variable response to chlorpyrifos treatment.•Half life of chlorpyrifos residue was found to be 4.02 days in rice soil.
Diazotrophs are one of the most important microbial communities which play a key role in rhizosphere to enhance plant growth-promotion by supplying fixed nitrogen to the plants. The aim of present ...study was to analyze the frequency and diversity of diazotrophs in the rhizospheres of five genotypes of aromatic rice (Oryza sativa cultivars Nua Kalajeera, Ketekijoha, Nua Desheri, Nua Chandan and Kala Namak) grown in ten years old long-term aromatic rice-rice (LARR) cropping system under sub-humid tropical condition. In this study, it was observed that very less frequency of active diazotrophs (0–14.28%) in the rhizosphere of aromatic rice genotypes based on polymerase chain reaction (PCR)-based nifH gene amplification, dot blot hybridization and acetylene reduction assay (ARA). The following five isolates (B10, B12, B29, BK16, NKR16) from rhizosphere of aromatic rice and the reference strain Azospirillum brasilence showed nifH amplification and positive signal for dot blot. None of these isolates showed positive in ARA test except A. brasilence. Basic local alighnment search tool (BLAST) homology of nifH sequences of B10, B12, B29, BK16 and NKR16 matched with Gluconoacetobacter diazotrophicus, Pseudomonas stutzeri, Klebsiella sp., Klebsiella pneumoniae and Sinorhizobium meliloti, respectively. Whereas, isolates B10, B12 and BK16 were identified as Bacillus cereus, Enterobacter sp., and Lysinibacillus sp., respectively based on 16S-rDNA sequencing. As per nifH sequences, these diazotrophs (B10, B12, B29, BK16, NKR16) fall under α and γ-proteobacter, whereas 16S-rDNA sequences revealed that they belonged to firmicutes and γ-proteobacter. Multiple sequence alignment of nifH gene sequences showed wider variation among diazotrophs, however 3D structure of NifH protein revealed the less diversity among isolates. Moreover, restriction digestion of 16S-rDNA using tetracutters (MspI, MboI and HaeIII) deciphered a unique pattern among small population of diazotrophs.The results of this finding provided an interesting data and novel information of diazotroph diversity in LARR cropping system. Finally, the present study indicated that the continuous application of high dose of inorganic nitrogenous fertilizers (nitrogen at the rate of 60 & 80kgNha−1year−1 in wet and dry seasons, respectively) limit the frequency and diversity of rhizospheric diazotrophs in the LARR cropping system.
The use of low-cost and ecofriendly adsorbents has been investigated as an ideal alternative to the current expensive methods of removing dyes from wastewater. This paper deals with the removal of ...Acid Red 114 (AR 114) from aqueous solutions using activated carbons prepared from agricultural waste materials such as gingelly (sesame) (Sp), cotton (Cp) and pongam (Pp) seed shells. Optimum conditions for AR 114 removal were found to be pH 3, adsorbent dosage
=
3
g/L of solution and equilibrium time
=
4
h. Higher removal percentages were observed at lower concentrations of AR 114. The adsorption isotherm data were fitted to Langmuir and Freundlich equation, and the adsorption capacity of the studied adsorbents was in the order Sp
>
Cp
>
Pp. Kinetic studies showed that the adsorption followed both pseudo-second-order and Elovich equation. The thermodynamics parameters such as Δ
G°, Δ
H°, Δ
S° were also evaluated. The activated carbons prepared were characterized by FT–IR, SEM and BET analysis.
Herein, a novel hybrid magnetic core-shell fibrous silica nanocomposite (RhB-Fe
3
O
4
/MnO
2
/SiO
2
/KCC-1) probe-based chemosensor was designed and its behaviour towards Cu(
ii
) metal ion was ...investigated using a fluorescence spectrometer. The organic receptor rhodamine B (RhB) fluorophore derivative was covalently grafted onto the surface of the magnetic core-shell fibrous silica nanocomposite. This sensing probe achieved the selectivity towards Cu(
ii
) in an aqueous solution, and other competing metal ions basically induced no spectral change. Thus, this sensing probe can work as a Cu(
ii
) selective fluorescent sensor. The synthesized material was characterized using transmission electron microscopy (TEM), scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), surface analysis (with BET), Fourier transform infrared spectroscopy (FT-IR), X-ray diffractometry, and thermogravimetric analysis (TGA). The rhodamine B derivative has a unique signalling probe that exhibits a turn-on fluorescence enhancement upon the recognition of Cu(
ii
) ion with an excitation at 569 nm. The linearity of the Stern-Volmer plot (
R
2
= 0.9882) and the detection limit of 12.3 × 10
−8
M were achieved. Finally, the sensor was tested to detect Cu(
ii
) ion in different real water samples.
Herein, a novel hybrid magnetic core-shell fibrous silica nanocomposite (RhB-Fe
3
O
4
/MnO
2
/SiO
2
/KCC-1) probe-based chemosensor was designed and its behaviour towards Cu(
ii
) metal ion was investigated using a fluorescence spectrometer.
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