Inorganic Fraction Research Articles

Modification of Inorganic Fractions of Phosphorus by Phosphate-Solubilising Microorganisms in Conjunction with Phosphorus Fertilisation in a Tropical Inceptisol

Modification of Inorganic Fractions of Phosphorus by Phosphate-Solubilising Microorganisms in Conjunction with Phosphorus Fertilisation in a Tropical Inceptisol

Organic fragments of k-carrageenan, lipids and peptides plus K-rich inorganic fraction in Kappaphycus alvarezii biomass are responsible for growth stimulus in rice plant when applied both foliar and root pathway

Kappaphycus alvarezii seaweeds regulate plant growth and development by modifying various metabolic functions. However, the substances responsible for the effects and relationship with the application pathway are poorly understood. This study aimed to structurally characterize biomass fractions and to evaluate the structure-bioativity relationship of different concentrations applied to the leaves and roots of rice plants (Oryza sativa L.). The aqueous extracts obtained from K. alvarezii were characterized by ATR-FTIR and 13C NMR CP/MAS, and their structures were compared by chemometrics. The composition was determined by CHN elemental analysis and atomic absorption. Bioactivity in plants was evaluated by foliar application (5 %, 10 %, 15 %, 20 % and 25 %) and root application (1 %, 2 %, 3 %, 5 % and 10 %), and the dry and fresh mass and root morphology were determined. The results show that the aqueous extract (KAlv-sapL) contains CAlkyl (26 %), CAlkyl-O,N (15 %), CAlkyl-O (23 %), CAlkyl-di-O (7 %), CAromatic-H,R (6 %), CAromatic-O,N (3 %), CCOOH-H,R (17 %) and CCO (3 %), belonging to fragments of k-carrageenan, lipids, and peptides; high amounts of K, P, Ca, Mg, Fe, Mn, Zn and Cu. KAlv-sapL applied via foliar treatment at 5 % and 10 % promoted increases in root and leaf dry mass by >30 % and 10 %, respectively, and 10 % of KAlv-sapL increased the area, diameter and number of roots by 11 %, 19 % and 40 %, respectively. Root application at 3 % (KAlv-sapL) stimulated the production of fresh and dry root mass by 60 % and 28 %, respectively, and when applied at 2 %, the root area, length, number and volume increased by 30 %, 50 %, 19 % and 31 %, respectively. In addition, the application at 2 % (KAlv-sapL) promoted intense mobilization and allocation of K+ in the leaves, increasing the uptake efficiency of this nutrient. The bioactivity of Kappaphycus seaweed occurs through joint action of carrageenan, lipids and peptides, and the inorganic fraction, rich in K+ and essential nutrients.

Heavy metal removal by the photosynthetic microbial biomat found within shallow unit process open water constructed wetlands

Nature-based solutions offer a sustainable alternative to labor and chemical intensive engineered treatment of metal-impaired waste streams. Shallow, unit process open water (UPOW) constructed wetlands represent a novel design where benthic photosynthetic microbial mats (biomat) coexist with sedimentary organic matter and inorganic (mineral) phases, creating an environment for multiple-phase interactions with soluble metals. To query the interplay of dissolved metals with inorganic and organic fractions, biomat was harvested from two distinct systems: the demonstration-scale UPOW within the Prado constructed wetlands complex (“Prado biomat”, 88 % inorganic) and a smaller pilot-scale system (“Mines Park (MP) biomat”, 48 % inorganic). Both biomats accumulated detectable background concentrations of metals of toxicological concern (Zn, Cu, Pb, and Ni) by assimilation from waters that did not exceed regulatory thresholds for these metals. Augmentation in laboratory microcosms with a mixture of these metals at ecotoxicologically relevant concentrations revealed a further capacity for metal removal (83–100 %). Experimental concentrations encapsulated the upper range of surface waters in the metal-impaired Tambo watershed in Peru, where a passive treatment technology such as this could be applied. Sequential extractions demonstrated that metal removal by mineral fractions is more important in Prado than MP biomat, possibly due to a higher proportion and mass of iron and other minerals from Prado-derived materials. Geochemical modeling using PHREEQC suggests that in addition to sorption/surface complexation of metals to mineral phases (modeled as iron (oxyhydr)oxides), diatom and bacterial functional groups (carboxyl, phosphoryl, and silanol) also play an important role in soluble metal removal. By comparing sequestered metal phases across these biomats with differing inorganic content, we propose that sorption/surface complexation and incorporation/assimilation of both inorganic and organic constituents of the biomat play a dominant role in metal removal potential by UPOW wetlands. This knowledge could be applied to passively treat metal impaired waters in analogous and remote regions.

Changing the Phosphate Regime of Soils in the Middle Taiga When Using Biochar

The influence of wood biochar on the content of various forms of phosphates was studied in laboratory experiments on soils with different phosphorus availability. Soils of the middle taiga subzone of Karelia were used in this work: a sandy Umbric Podzol and a heavy loamy Umbric Retisol. The tests studied the effect of two fractions of biochar (3–5 and ≤2 mm) in an amount of 2% and 5% of soil mass on pHKCl, the content of available and total phosphorus, the inorganic phosphorus fractions (Chang-Jackson method), and the total phosphatase activity of soils, as well as the effect of separate and combined application of biochar and fertilizer (NPK) on the content of available phosphorus in a pot experiment with spring barley. The research revealed that biochar significantly increased the content of available phosphorus by 20–40%, increased the content of the fraction of Ca-bounded P, Al-bounded P and loosely-bounded P, and also increased the phosphatase activity in the Umbric Podzol. In pot experiment was noted a higher content of P2O5 in variants with biochar ≤2 mm, in variants with fertilizer, and a significant mutual influence factors of biochar and fertilizer. Biochar increased the content of available phosphorus by 2–6%, increased the content of Ca-bounded P and loosely-bounded P (with biochar ≤2 mm at 5% dosage), and had no significant effect on the phosphatase activity in the Umbric Retisol. Only combination of biochar ≤2 mm and fertilizer had a significant effect in pot experiment with Umbric Retisol. In general, the most noticeable effect on almost all studied indicators was provided by ≤2 mm fraction of biochar in a 5% dosage. The use of biochar led to statistically significant increase in pHKCl values, and did not affect the content of total phosphorus in both soils. Biochar had a greater effect on the phosphate regime of coarse-textured soil with an initially lower pH and a less content of available and total phosphorus.

Development of a New Analytical Method for the Characterization and Quantification of the Organic and Inorganic Carbonaceous Fractions in Snow Samples Using TOC and TOT Analysis

Different Light-Absorbing Snow Impurities (LASI) can deposit on snow- and ice-covered surfaces. These particles are able to decrease snow and ice albedo and trigger positive albedo feedback. The aim of this work was to develop a new method to quantify the carbonaceous fractions that are present in snow and ice samples that contribute significantly to their darkening. Currently, in the literature, there is an absence of a unified and accepted method to perform these studies. To set up the method proposed here, snow samples were collected at two Italian locations, Claviere and Val di Pejo (Northern Italy). The samples were analyzed using two main techniques, Total Organic Carbon analysis (TOC analysis) and Thermal Optical analysis in Transmittance mode (TOT), which enabled the speciation of the carbonaceous fraction into organic (OC), inorganic (IC), and elemental carbon (EC), and further into the soluble and insoluble parts. The results highlighted a correlation between the nature of the sample (i.e., location, age, and exposure of the snow) and the experimental results, giving validity to the method. For example, the abundant presence of terrigenous constituents was reflected in high amounts of insoluble IC. Moreover, due to the trend between insoluble IC and Elemental Carbon (EC), the role of IC in TOT analysis was investigated. Indeed, IC turned out to be an interfering agent, suggesting that the two techniques (TOC analysis and TOT) are complementary and therefore need to be used in parallel when performing these studies. Finally, the results obtained indicate that the newly proposed method is suitable for studying the carbonaceous fractions in snow samples.

Air pollution combined with high-fat feeding aggravates metabolic and cardiovascular diseases: A dangerous, oxidative, and immune-inflammatory association

Obesity and particulate air pollutant (PM2.5) are important risk factors for cardiometabolic diseases. PM2.5 exacerbates insulin resistance and lipid ectopic deposition in obese animals. The inorganic fraction of PM2.5, the Residual Oil Fly Ash (ROFA), is related to cardiovascular events, by enhancing the generation of reactive species, inflammatory cytokines, and leukocyte activation. However, the synergistic effects of ROFA and a high-fat diet (HFD) are still poorly described, and the studies were mainly conducted with males. AimsTo investigate if ROFA could potentiate the cardiometabolic effects of diet-induced obesity in female rats. Material and methodsWistar female rats were divided into four groups: Control (n = 6), Polluted (n = 6), HFD (n = 6), and HFD + Polluted (n = 6). HFD and HFD + Polluted received a high-fat diet (HFD) (58.3 % as fats), whilst Control and Polluted groups received a standard diet (Nuvilab CR-1). In addition, Polluted and HFD + Polluted groups received intranasal instillation of ROFA (250 μg/50 μL), while Control and HFD groups received saline solution (50 μL) daily, five days per week. Both interventions occurred 24 weeks after the animals were euthanized. Key findingsHFD combined with ROFA exposure impaired lipid profile challenged systemic and cardiac antioxidant defense, and presented a synergistic effect in inducing an immune-inflammatory condition. We found that the lipid profile disturbance is associated with HFD-induced hepatic, but not cardiac, deposition of triglycerides in female animals. SignificanceOur results support the hypothesis that ROFA exposure combined with bad feeding can exacerbate metabolic and cardiovascular diseases.

Role of sulphur and chlorine in condensable particulate matter formation during coal combustion.

Condensable particulate matter (CPM) is a major component of primary particulate matter emitted into the atmosphere from stationary sources. However, the factors affecting CPM generation remain unclear. In this study, we systematically investigated the role of sulphur and chlorine in CPM formation during coal combustion. To explore the influence of S, various concentrations of SO2 (0-2000ppm) were added to the combustion process of high-S coal. The role of Cl in the generation of CPM was revealed by burning coal with a significant difference in the Cl content (0.51-9.70mg/g). The results show that addition of SO2, especially in SO42-, to the combustion process increases the CPM inorganic fraction content from 5.83 to 48.3mg/m3. In addition, we speculated that the presence of SO2 may have led post-break oxidation of long-chain alkanes to form esters, especially phthalates. At the same time, in experiments concerning Cl, the opposite trend was observed between S and Cl in the CPM inorganic fraction. As the Cl content in the fuel increased, the S content in the inorganic fraction of CPM gradually decreased. This is because Cl inhibits the conversion of SO2 to SO3, therefore, less S forms CPM as SO3 or as sulphides.

A Systematic Review on the Synthesis of Silicon Carbide: An Alternative Approach to Valorisation of Residual Municipal Solid Waste

Over the past several decades, industrialised and developing nations have attempted to enhance sustainability. Demands for energy and the acceleration in environmental deterioration are the two primary obstacles to progress. The daily generation of municipal solid waste has been a significant factor in the deterioration of the ecology. To address this issue, a considerable amount of municipal solid waste may be used to synthesise SiC nanomaterials from organic and inorganic fractions and use them as carbon and silica sources. Nanomaterials have progressively received widespread prominence as the development of particulate materials accelerates at an incredible rate. One such material is silicon carbide (SiC), which has garnered considerable interest due to its remarkable performance and wide variety of applications. This review article discusses the SiC polytypes, including cubic, hexagonal, and rhombohedral SiC. The characteristics of silicon carbide, such as its biomimetic, surface, and thermal properties, are also discussed. In addition, the synthesis of silicon carbide was described in depth, including microwave sintering, the calcination method, the carbothermal redox reaction, and much more. The final section describes the applications of silicon carbide, including wastewater treatment, medical implants, and gas detection.

Unified analysis method for total and inorganic As determination in foodstuffs by hydride generation high-resolution continuum source quartz tube atomic absorption spectrometry.

A unified analytical method applicable to common foodstuff matrices was developed and characterized for total and inorganic arsenic determination by hydride generation high-resolution continuum source quartz tube atomic absorption spectrometry, which was established based on different sample preparation procedures. This new method was found to be interference-free and cost-effective in terms of reagents consumption for sample preparation and derivatization to arsine for the inorganic arsenic fraction. Microwave-assisted digestion in HNO3-H2O2 for total arsenic and extraction in 0.28 mol L-1 HNO3 by mechanical stirring in a water bath or ultrasound-assisted extraction in 0.01 mol L-1 HCl without separation of inorganic As, all coupled with arsine generation in 0.01 mol L-1 HCl medium with 0.6% NaBH4 in 0.01% NaOH in the presence of 0.2% L-cysteine was found to be suitable for all matrices. The results were statistically compared by applying Tukey's and Dunnett's multiple comparison methods (p > 0.05). The use of external calibration with As(III) standards and standard addition method for quantification showed the lack of non-spectral interferences from the multimineral matrices, resulting in a reliable method for total/inorganic As determination in various foodstuffs. The limits of detection for total/inorganic As using peak height measurement were 0.0044 ± 0.0005/0.0022 ± 0.0003 mg kg-1 (n = 25 days). The overall recovery for total/inorganic As in the certified reference materials was in the range of 98% ± 22%, and 99% ± 24% (k = 2). The extraction of inorganic As in 0.01 mol L-1 HCl and 0.28 mol L-1 HNO3 provided the recovery of 106% ± 25% and 100% ± 25% (k = 2), which was better than in 10 mol L-1 HCl. The precision of measurements in real samples of fish muscle, meat and organs, rice and rice-based baby foods with contents of 0.052-5.29 mg kg-1 total As and 0.005-0.063 mg kg-1 inorganic As was 9.8-18.8% and 8.7-32.0%, respectively, which was calculated based on the combined uncertainty.

Mutagenicity of the organic fraction of World Trade Center dust.

Most studies of the health effects and chemical characterization of the dust resulting from the catastrophic collapse of the World Trade Center (WTC) on September 11, 2001, have focused on the large inorganic fraction of the dust; however, chemical analyses have identified mutagens and carcinogens in the smaller organic fraction. Here, we determined the mutagenicity of the organic fraction of WTC dust in Salmonella. Only 0.74% of the mass of the particulate matter (PM) <53 μm in diameter was extractable organic matter (EOM). Because the EOM was 10 times more mutagenic in TA100 +S9 than in TA98 +S9 and was negative in TA98 -S9, we inferred, respectively, that polycyclic aromatic hydrocarbons (PAHs) played a role in the mutagenicity and not nitroarenes. In TA98 +S9, the mutagenic potency of the EOM (0.1 revertant/μg EOM) was within the range of EOMs from air and combustion emissions. However, the EOM-based mutagenic potency of the particles (0.0007 revertants/μg PM) was 1-2 orders of magnitude lower than values from a review of 50 combustion emissions and various air samples. We calculated that 37 PAHs analyzed previously in WTC EOM were 5.4% of the EOM mass and 0.04% of the PM mass; some air contained 0.3 μg WTC EOM/m3 (0.02 μg PAHs/m3 ). Populations exposed to WTC dust have elevated levels of prostate and thyroid cancer but not lung cancer. Our data support earlier estimates that PAH-associated cancer risk among this population, for example, PAH-associated lung cancer, was unlikely to be significantly elevated relative to background PAH exposures.

Storm chasing: Tracking Holocene storminess in southern Sweden using mineral proxies from inland and coastal peat bogs

Severe extratropical winter storms are a recurrent feature of the European climate and cause widespread socioeconomic losses. Due to insufficient long-term data, it remains unclear whether storminess has shown a notable response to changes in external forcing over the past millennia, which impacts our ability to project future storminess in a changing climate. Reconstructing past storm variability is essential to improving our understanding of storms on these longer, missing timescales. Peat sequences from coastal ombrotrophic bogs are increasingly used for this purpose, where greater quantities of coarser grained beach sand are deposited by strong winds during storm events. Moving inland however, storm intensity decreases, as does sand availability, muting potential paleostorm signals in bogs. We circumvent these issues by taking the innovative approach of using mid-infrared (MIR) spectral data, supported by elemental information, from the inorganic fraction of Store Mosse Dune South (SMDS), a 5000-year-old sequence from a large peatland located in southern Sweden. We infer past changes in mineral composition and thereby, the grain size of the deposited material. The record is dominated by quartz, whose coarse nature was confirmed through analyses of potential local source sediments. This was supported by further mineralogical and elemental proxies of atmospheric input. Comparison of SMDS with within-bog and regionally relevant records showed that there is a difference in proxy and site response to what should be similar timing in shifts in storminess over the ∼100 km transect considered. We suggest the construction of regional storm stacks, built here by applying changepoint modelling to four transect sites jointly. This modelling approach has the effect of reinforcing signals in common while reducing the influence of random noise. The resulting Southern Sweden-Storm Stack dates stormier periods to 4495–4290, 3880–3790, 2885–2855, 2300–2005, 1175–1065 and 715-425 cal yr BP. By comparing with a newly constructed Western Scotland-Storm Stack and proximal dune records, we argue that regional storm stacks allow us to better compare past storminess over wider areas, gauge storm track movements and by extension, increase our understanding of the drivers of storminess on centennial to millennial timescales.

TEGDMA-Functionalized Dicalcium Phosphate Dihydrate Resin-Based Composites Prevent Secondary Caries in an In Vitro Biofilm Model.

This study evaluated the efficacy of experimental TEGDMA-functionalized dicalcium phosphate dihydrate (T-DCPD) filler-based resin-based composites (RBC) in preventing caries lesions around the restoration margins (secondary caries, SC). Standardized Class-II cavities were made in sound molars with the cervical margin in dentin. Cavities were filled with a commercial resin-modified glass-ionomer cement (RMGIC) or experimental RBCs containing a bisGMA-TEGDMA resin blend and one of the following inorganic fractions: 60 wt.% Ba glass (RBC-0); 40 wt.% Ba glass and 20 wt.% T-DCPD (RBC-20); or 20 wt.% Ba glass and 40 wt.% T-DCPD (RBC-40). An open-system bioreactor produced Streptococcus mutans biofilm-driven SC. Specimens were scanned using micro-CT to evaluate demineralization depths. Scanning electron microscopy and energy-dispersive X-ray spectroscopy characterized the specimen surfaces, and antimicrobial activity, buffering effect, and ion uptake by the biofilms were also evaluated. ANOVA and Tukey's tests were applied at p &lt; 0.05. RBC-0 and RBC-20 showed SC development in dentin, while RBC-40 and RMGIC significantly reduced the lesion depth at the restoration margin (p &lt; 0.0001). Initial enamel demineralization could be observed only around the RBC-0 and RBC-20 restorations. Direct antibiofilm activity can explain SC reduction by RMGIC, whereas a buffering effect on the acidogenicity of biofilm can explain the behavior of RBC-40. Experimental RBC with CaP-releasing functionalized T-DCPD filler could prevent SC with the same efficacy as F-releasing materials.

Water quality parameters and constituent concentrations measured in the Peel and Arctic Red Rivers, 2007–2010

Outflow from north-flowing circumpolar rivers has a strong influence on the Arctic Ocean. The Peel and Arctic Red Rivers are tributaries of the Mackenzie Delta, a large, lake-rich floodplain that forms the interface between the Mackenzie River and the Beaufort Sea basin of the Arctic Ocean. Here, we present water quality data that were collected from the Peel and Arctic Red Rivers between 2007 and 2010 as part of an International Polar Year project that investigated the seasonal hydrology and biogeochemistry of the Mackenzie River and its delta. The Peel River was sampled 57 times between May 2007 and September 2010 upstream of the community of Fort McPherson, Northwest Territories (NT), while the Arctic Red River was sampled 32 times between May 2007 and August 2008 (with one additional sample in June 2010) approximately 0.5 km upstream of its confluence with the Mackenzie River near the community of Tsiigehtchic, NT. Each water sample was analyzed for up to 22 water quality parameters, including water temperature, specific conductivity, pH, chlorophyll a, total suspended sediments, particulate nutrients (carbon, nitrogen, and phosphorus), soluble reactive silica, major ions (calcium, magnesium, potassium, sodium, chloride, and sulfate), dissolved carbon (inorganic and organic fractions), and dissolved nutrients (three nitrogen and two phosphorus fractions). This data set, which is available for download and reuse, provides important baseline information about water quality in the Peel and Arctic Red Rivers, complements other data that have been collected in these watersheds, and will be of interest to researchers, resource managers, Indigenous organizations, and governments that are active in the region.

Factors influencing aerosol and precipitation ion chemistry in urban background of Moscow megacity

In-depth study of aerosol and precipitation ion chemistry was carried out in order to cover an existing data gap in the seasonal-dependent ionic data in Moscow urban background atmosphere. Literature about atmospheric pollution in this megacity is, indeed, still poor, despite its peculiar climatological characteristics that make it a very interesting site for atmospheric research. Particulate matter (PM) and precipitation were collected at Moscow urban background during spring of 2018, summer, and autumn of 2019. Aerosol inorganic ions are characterized for the whole period, carboxylic acids and sugars for summer. Inorganic ions constitute a major PM10 fraction of 27% in autumn, it drops down to 16.5% in summer. Dominance of secondary inorganic aerosol (SIA) over all the other inorganic ion species is determined. Na+ and Ca2+ shows the largest variability between seasons, with maximum in summer and spring, respectively. Excess of anions in autumn is indicated by ion balance while adding carbonates, spring and summer aerosol is found electroneutral. Chloride depletion phenomenon follows the snow melt and remobilization of salt applied to roads for deicing, demonstrating the biggest impact in summer. Degree of neutralization of ammonia as sulfate and nitrate is found by the correlation between the concentration of NH4+ and calculated from SO42− and NO3−. Inorganic fraction in PM10 is higher (16.5%) than total carboxylic acids (3.5%), and total sugars and anhydrosugars (0.8%). Concentration polar plots show ion variation jointly with wind speed and wind direction and the source origin. Highest SIA concentrations relate a cluster of the prevalent air mass transportation and indicate the source in the northwestern direction in spring and summer. K+ acts as a marker of fires in spring and summer as well as of the domestic biomass burning in the region around a megacity in autumn. Source apportionment of inorganic ion and BC by Varimax analysis reveals major sources namely SIA, soil resuspension, biomass burning, deicing salt, and fossil fuel combustion. In summer, organic ions, anhydrosugars, and sugars shows additional impact of photochemistry and biological activities. Rainfall is heavier in summer than in autumn, with pH of acid rain during spring and summer. The highest concentrations for almost all ions were observed in spring, except HCO3−. Precipitation composition is described with aerosol wet removal by seasonal variability of SIA scavenging factors, decreasing in summer and increasing in autumn and spring.

Phosphorus Fractions in Temperate Grassland Soils and Their Interactions with Agronomic P Tests

Phosphorus (P) is a major nutrient for plant growth and animal health, and its availability in soil is influenced by agronomic management and soil properties. This study examined the distribution of labile and non-labile soil P fractions in grassland and the properties that influence their distribution in temperate grasslands. Eleven fractions were identified as, labile (H2O.P and NaHCO3.P), moderately labile (NaOH.P) and plant non-available (NaOH.P, HCl.P and residual P). The residual P, moderately labile organic (NaOH.Po) and inorganic (NaOH.Pi) fractions comprised 38%, 24% and 15% of the total P (TP), respectively. The residual and organic (Po) fractions were associated with extractable Fe, and the NaOH.Pi fraction was associated with extractable Al. Agronomic reagents (Morgan’s and Mehlich3) targeted specific fractions based on their affinity for different soil elements. Morgan’s P was associated with extractable and residual Ca and in high Ca soils, and overestimated plant-available P by extracting non-labile Ca.P forms (HCl.P). The Mehlich3 P test was associated with NaOH.Pi fraction and showed a preference for Al.P oxides. This study indicates that Mehlich3 reagent, which provides a wider suite of elements such as P, Ca, Al and Fe, will suit as a better indicator for soil P dynamics and improved P advice to farmers. The inclusion of additional soil chemico-physical characteristics would improve agronomic soil testing, benefitting farmers’ advice.

The Phosphorus Availability in Mollisol Is Determined by Inorganic Phosphorus Fraction under Long-Term Different Phosphorus Fertilization Regimes

Understanding the effects of a fertilization regime on the long-term accumulation and transformation of soil phosphorus (P) is essential for promoting the development of sustainable management of soil P. Based on a 29-year field experiment in Mollisol, the compositions and changes of P forms using a modified Hedley sequential extraction method, solution 31P-NMR and P K-edge XANES and soil properties were investigated under continuous mono maize with and without manure (NPKM and NPK). Results showed a stronger positive related coefficient between soil total P and labile P, and mid-labile P fraction was found in NPKM than in NPK treatment. It indicated NPKM could improve the availability of soil accumulated P and reduce its transformation to stable P. Accumulated inorganic P (Pi) was dominated by aluminum phosphate (Al-P) and monobasic calcium phosphate monohydrate (MCP) for NPK treatment, Al-P, MCP, and tricalcium phosphate for NPKM treatment with XANES analysis, which contributed to the P availability in Mollisol. Moreover, the proportion of IHP with XANES and ratio of orthophosphate diesters to monoesters in NPK compared to NPKM indicated the higher Po lability with NPK treatment. Pi, especially NaHCO3-Pi and NaOH-Pi, were the potential sources of resin-Pi. Soil organic matter (SOM), organic-bound iron, and alumina oxide (Fep + Alp) showed significant influence on the transformation of P forms. Our research suggested that due to the rise in SOM and Fep + Alp, the fertilization regime significantly increased most highly active soil P fractions, especially in NPKM treatment. This work gives new insight into sustainable P management, which benefits the reduction in soil P accumulation.

Phosphorus in alkaline soils of the semiarid region, Brazil: inorganic fractions, capacity factor, and availability

The study was designed to quantify the contents of Pi fractions and correlate them with the P capacity factor of soils in the Brazilian semiarid region. We also evaluated the effect of soil P doses contact time and P availability for maize plants in alkaline soils of the Brazilian semiarid region. Soil samples were collected between the Piranhas-Açu (RN) and Jaguaribe (CE) rivers valleys. The maximum phosphate sorption capacity was highly correlated with the values of remaining P, indicating that it can be used as a measure to estimate the P capacity factor of these soils. Maximum P sorption capacity correlated with Fe2O3 and Ca2+ contents and pH values. These results demonstrate that P sorption is explained by P adsorption on the surface of iron oxides and by its precipitation with Ca2+ in alkaline soils. The contact time increases promote plant P contents decreased substantially in the first 30 to 60 days after fertilization and decreased until 120 days of incubation but then tended to stabilize at the longest soil P contact times.

The investigation of composition and thermal behavior of two types of backfilling gutta-percha

Background/purposeIn the warm gutta-percha technique, soft-type and regular-type gutta-percha are using for backfilling thermoplasticized injection system. However, there are limited reports about the properties of these backfilling gutta-percha. This study aimed to analyze and compare the composition, thermal behavior and compact force of two types of backfilling gutta-percha. Materials and methodsSoft-type and regular-type backfilling gutta-percha (B&L BioTech, Fairfax, VA, USA) were investigated. The inorganic and organic fractions of these gutta-perchas were separated by quantitative chemical analysis (n = 6). Their composition was analyzed using energy dispersive spectroscopy. Thermal behavior in response to temperature variations was analyzed using differential scanning calorimetry. Additionally, a compaction model was used to investigate the relation between compaction force and temperature (n = 10). ResultsThe soft-type contained more gutta-percha (3.69–5.85%), carbon ratio (38.96–48.52%) and less inorganic substance (86.51–90.45%), zinc ratio (29.36–35.67%). The composition ratio of two types gutta-percha were statistically significant different (P < 0.05). There were three phase transitions of the soft-type gutta-percha which started at 39.84 °C, 49.32 °C and 54.15 °C while the two phase transitions of the regular-type gutta-percha started at 40.48 °C and 53.45 °C. The glass transition temperature of the regular-type gutta-percha (44.24 °C) was higher than that of the soft-type gutta-percha (40.66 °C). Under various setting temperature, the higher compaction force in the regular-type gutta-percha was required (P < 0.05). ConclusionThe different components in gutta-percha contribute to its differences in thermal behavior. The soft-type had a higher proportion of gutta-percha and lower ZnO which makes the fluidity better than the regular-type.

Long-term Impact of Soil Test and Targeted Yield Based Nutrient Management on Vertical Variability in Carbon Fractions of a Vertisol under Rice-wheat Cropping Sequence

Aim: To study the Long-term impact of soil test and targeted yield based nutrient management on vertical variability in carbon fractions of a Vertisol under rice-wheat cropping sequence.&#x0D; Place and Duration of Study: This research trail was conducted during rabi season of 2020-21 in an on-going research programme of AICRP on STCR initiated during 2008 at the Research Farm of Jawaharlal Nehru Krishi Vishwa Vidyalaya, Jabalpur.&#x0D; Study Design: The study has consisted of six treatments of nutrient management practices based on soil test and targeted yields of rice and wheat (T1: Control; T2: GRD; T3: T.Y. 50 and 45 q ha-1 for rice and wheat; T4: T.Y. 60 q ha-1; T5: T.Y. 50 and 45 q with FYM 5 t ha-1 for rice and wheat and T6: T.Y. 60 q with 5 t FYM ha-1) at different soil depths (0-15, 15-30 and 30-45 cm) which were replicated four times in a randomized block design.A total of 72 post- harvest soil samples of wheat were subjected to determination of carbon fractions across the soil depths.&#x0D; Results: Results revealed that Carbon fractions in soil were significantly altered by nutrient management practices over soil depths. However, the highest contents of organic and inorganic carbon fractions in soil were obtained under T6 having highest yield target of 60 q along with FYM 5 t ha-1 and the lowest in control. The results showed that contents of carbon fractions of soil were decreased with consecutive increase in soil depths except less labile carbon and inorganic carbon which increased with soil depths.

Impacts of marine organic emissions on low-level stratiform clouds – a large eddy simulator study

Abstract. The goal of this study is to investigate the role of organic aerosols emitted with sea spray or formed from marine gas phase emissions of volatile organic compounds (VOCs) in influencing the stability of stratiform marine clouds. We aim to point out the processes and drivers that could be relevant for global climate and should thus be considered in large-scale models. We employ a large eddy simulator coupled with an aerosol–cloud microphysical model together with different parameterizations for emission of sea salt, primary organic aerosol, and VOCs from sea surface and formation of secondary organic aerosol (SOA), to simulate the conditions of the second Dynamics and Chemistry of Marine Stratocumulus observational campaign characterized by low-level stratocumulus clouds transitioning from closed cells to drizzling open cell structure. We find that the inclusion of sea spray emissions can both extend and shorten the transitioning timescale between closed and open cells based on the parameterization employed. Fine sea spray provides extra cloud condensation nuclei (CCN) and delays the onset of drizzle as the collision–coalescence process is slowed down due to smaller cloud droplet mean size. The coarse mode has an opposite effect due to giant CCN (GCCN) speeding up the drizzle formation through the enhanced collision–coalescence processes. The balance between two processes depends on the model parameterization employed. Compared to differences between different sea spray parameterizations, the sensitivity of the clouds to the variations in organic fraction of sea spray and hygroscopicity of the emitted particles is relatively limited. However, our results show that it is important to account for the size dependence of the sea spray organic fraction as attributing organic emissions to coarse mode noticeably reduces the GCCN effect. In addition, including the secondary organic aerosol formation from VOCs can potentially have a noticeable impact, but only when emitting the highest observed fluxes of monoterpenes. This impact is also highly sensitive on the size distribution of the background aerosol population. SOA production from isoprene is visible only if aqueous phase SOA production pathways are included, and even then, the effect is lower than from monoterpenes.