Increase In Nitrogen Content Research Articles

Influence of climate change on water quality in Terra Nova River basin, Pernambuco, Brazil

Climate changes tend to intensify water scarcity in arid and semi-arid regions, making water management in these areas more challenging, directly influencing hydrological dynamics, causing impacts on ecosystems and society. The Terra Nova River basin is crucial for the water security of the semi-arid region of Pernambuco, especially after the construction of the São Francisco River Integration Project (PISF), which saw the construction of six reservoirs to supply water for human consumption, agricultural, and industrial activities. Therefore, this study aims to analyzes the impacts of climate changes on water quality in the Terra Nova River basin in Pernambuco, using long-term data from the Hydrological Response Unit System for Pernambuco (SUPer). The ARIMA (Autoregressive Integrated Moving Averages) model is employed to predict water quality parameters in climate change scenarios, using data from the Intergovernmental Panel on Climate Change (IPCC) and the Oswaldo Cruz Foundation (Fiocruz). The variables include air temperature, precipitation, dissolved oxygen, nitrogen, and phosphorus. Simulated scenarios were compared with CONAMA No. 357/2005 limits, revealing potential decreases in dissolved oxygen and phosphorus concentrations, alongside an increase in nitrogen concentrations. Irregular rainfall rates, high air temperatures, and evapotranspiration, combined with conflicts by water resources, may exacerbate water access issues in the semi-arid region, worsening the water crisis and threatening water security.

Effects of Microbial Organic Fertilizer, Microbial Inoculant, and Quicklime on Soil Microbial Community Composition in Pepper (Capsicum annuum L.) Continuous Cropping System

The additions of microbial organic fertilizer (MOF), a microbial inoculant (MI), and quicklime (Q) are considered to be sustainable practices to restore land that has been damaged by continuous cropping of pepper (Capsicum annuum L.). However, the combined effects of these three additives on pepper yield, soil chemical properties, and soil microbial communities were unclear. The experimental design consists of 13 treatment groups: the untreated soil (control); soil amended solely with three treatments for each of MOF (1875–5625 kg ha−1), MI (150–450 mL plant−1), and Q (1500–4500 kg ha−1); and soil amended with combinations of MOF, MI, and Q at three comparable concentrations. A significant increase in pepper fruit diameter, length, yield, and soil available nitrogen, phosphorus, and potassium contents occurs upon exclusive and combined applications of MOF, MI, and Q. Pepper yield was greatest (29.89% more than control values) in the combined treatment with concentrations of 1875 kg ha−1 MOF, 150 mL plant−1 MI, and 1500 kg ha−1 Q. The application of Q increased soil pH and reduced soil–fungal richness. The application of MOF, MI, and Q increased the relative abundance of bacterial genera and the complexity of bacterial and fungal co-occurrence networks compared with control levels. The combined application of MOF, MI, and Q resulted in the greatest microbial network complexity. A Mantel test revealed the key role of soil available nitrogen content and bacterial diversity in the regulation of pepper growth and yield. We conclude that the combined application of MOF, MI, and Q improves soil nutrient availability and modifies soil microbial community composition, significantly promoting plant growth and pepper yield during continuous cultivation.

Inoculation with Azospirillum brasilense as a Strategy to Reduce Nitrogen Fertilization in Cultivating Purple Maize (Zea mays L.) in the Inter-Andean Valleys of Peru.

Purple maize has gained global significance due to its numerous nutraceutical benefits. However, sustaining its production typically requires high doses of nitrogen fertilizers, which, when applied in excess, can contaminate vital resources such as soil and water. Inoculation with nitrogen-fixing microorganisms, such as those from the Azospirillum genus, has emerged as an alternative to partially or fully replace nitrogen fertilizers. This study aimed to evaluate the inoculation effect with A. brasilense and varying nitrogen fertilization levels on the yield and quality of purple maize. The experiment was carried out using a randomized complete block design (RCBD) with a 2 × 5 factorial arrangement and five replications. Treatments comprised two inoculation levels (control without inoculation and inoculation with A. brasilense) under five nitrogen doses (0, 30, 60, 90, and 120 kg∙ha-1, applied as urea). Inoculation with A. brasilense resulted in a 10.5% increase in plant height, a 16.7% increase in root length, a 21.3% increase in aboveground fresh biomass, a 30.1% increase in root fresh biomass, and a 27.7% increase in leaf nitrogen concentration compared to the non-inoculated control. Regarding yield, the inoculated plants surpassed the control in both purple maize yield (kg∙ha-1) and cob weight by 21.8% and 11.6%, respectively. Across all fertilization levels and parameters assessed, the inoculated treatments outperformed the control. Furthermore, for parameters, namely plant height, leaf nitrogen content, and cob dimensions (length, diameter, and weight), the A. brasilense inoculation treatment with 90 kg N∙ha-1 was statistically equivalent or superior to the non-inoculated control with 120 kg N∙ha-1. These results indicate that inoculation with A. brasilense positively impacted purple maize at all nitrogen levels tested and improved nitrogen use efficiency, enabling a reduction of 30 kg N∙ha-1 without compromising performance in key parameters.

Combined effect of molybdenum and nitrogen fertilization on nitrogen metabolism and amino acid content in tobacco leaves

IntroductionThis study investigated the combined effects of molybdenum (Mo) and nitrogen (N) fertilization on N metabolism and amino acid content in the leaves of flue-cured tobacco (Nicotiana tabacum L.) during its mature stage through a pot experiment.MethodsDifferent application levels of Mo (0, 0.15, 0.30 mg/kg soil) and N (0.06, 0.24, 0.42 g/kg soil) were set to observe and analyze changes in leaf quality, N, and amino acid content in the tobacco plants.ResultsThe results revealed that the N fertilizer application level exhibited a primary effect on regulating the total nitrogen, nitrate nitrogen, soluble protein, and amino acid nitrogen concentrations within tobacco leaves, while the effectiveness of Mo fertilization was influenced by the level of N applied. Specifically, under the conditions of 0.24 g/kg soil N and 0.30 mg/kg soil Mo application, the N content, N accumulation, and dry matter mass of the tobacco plants increased significantly by 110%, 204%, and 48%, respectively. Concurrently, nitrate reductase activity increased by 107-fold, and the nitrate nitrogen content was relatively low, contributing to enhanced tobacco yield and safety. Moreover, this treatment led to a notable (170%) increase in free amino acid nitrogen content, with minimal impact on total amino acids and soluble proteins. Notably, it effectively increased the content of free amino acids beneficial to the sensory quality of tobacco (such as histidine, arginine, aspartic acid, isoleucine, and glutamic acid) without reducing the total amino acid content, while simultaneously reducing other amino acids that might affect quality. Therefore, the combined application of 0.30 mg/kg soil Mo and 0.24 g/kg soil N specifically optimized the amino acid composition in tobacco leaves, positively impacting overall quality and market competitiveness.DiscussionThis study provides a theoretical basis for the rational application of Mo fertilizer in Mo-deficient areas to improve the yield and quality of flue-cured tobacco.

Exploring the adaptive mechanisms and strategies of various populations of Sporobolus ioclados in response to arid conditions in Cholistan desert

This study explored the drought resistance mechanisms of different populations of Sporobolus ioclados (Poaceae), locally known as “Sawri,” “Drabhri” and “Dhrbholi” native to Africa and the Indian Subcontinent. These populations were grown in conventional nursery practices at Khawaja Fareed Government College in Rahim Yar Khan, Pakistan, and subsequently subjected to four distinct levels of drought within carefully monitored experimental settings. The experiment was conducted in a two-factorial design involving populations and drought treatments and was repeated three times. The physiological and morphological responses of S. ioclados, including plant height, number of roots, root length, flag leaf area, stomatal features, proline concentration and nitrogen content, displayed significant variability in response to the imposed drought stress. Drought resulted in increases in proline concentration and nitrogen content. The number of roots decreased, while the length and width of the stomata increased in various populations. A combination of advanced statistical techniques, such as ANOVA, PCA, HCA, and DFA, provided a comprehensive understanding of the mechanism of plant adaptation and the extent of population diversity within the species. The Yazman and Nwab Wala populations exhibited the highest rates of photosynthesis and stomatal conductance, while S. ioclados demonstrated notable drought tolerance at the T4 level of drought stress. A negative correlation was found between proline levels, nitrogen contents, and photosynthesis, suggesting that proline has a protective role in drought. The diverse adaptation strategies indicated by S. ioclados populations have revealed the potential of this species for afforestation and climate change mitigation in dry environments.

The influence of nitrogen content on the microstructure and properties of W-Ta-Cr-V-N refractory high-entropy nitrides

To enhance the mechanical performance and corrosion resistance of refractory high-entropy alloys (RHEAs) and to identify materials better suited for severe high-temperature and corrosive environments, this study utilized a double glow plasma surface alloying technique to fabricate a W-Ta-Cr-V-N refractory high-entropy nitride coating on a W substrate. The microstructure and phase structure of the samples were characterized using a scanning electron microscope and X-ray diffractometer. The mechanical properties of the samples were evaluated through microhardness testing, while their corrosion performance was assessed by potentiodynamic polarization and electrochemical impedance spectroscopy measurements. The study investigated the effects of different nitrogen contents on the microstructure, mechanical properties, and corrosion resistance of the BCC-structured W-Ta-Cr-V alloy in the past tense. The study found that the doping of an appropriate amount of nitrogen can lead to the formation of FCC and HCP structured nitrides. As the nitrogen content increases, there is a significant change in the preferred orientation of the coating. When the nitrogen content is 16.6 at.%, the distribution of the nitrides is uneven, resulting in increased surface undulations and roughness. Conversely, when the nitrogen content is elevated to 48.1 at.%, the clustering of surface nitride particles becomes more pronounced, leading to a decrease in the coating density. The thickness of the nitride coatings is around 10 μm, with a slight decrease in thickness as the nitrogen content increases. The hardness of the coatings is significantly superior to that of the W-Ta-Cr-V alloy films, reaching up to 3465 HV0.25 in the highest instance. The introduction of 31.4 at.% nitrogen results in the densest coating, effectively enhancing the corrosion resistance of the refractory high-entropy alloy. Therefore, the doping of an appropriate amount of nitrogen can alter the microstructure of the refractory high-entropy alloy, improve its mechanical properties, and enhance its chemical stability.

Effect of nitrogen on the microstructure and strengthening mechanism of high performance tinplate

In order to meet the high strength and high formability requirements of the tinplate market, the nitrogen strengthening method was used for the chemical composition of the tinplate, and the action mechanism of nitrogen on the full-process tinplate substrate was explored. The present study designed tinplate with different nitrogen contents (named as 20N steel and 150N steel), and conducted phase transformation research and recrystallization temperature tests. SEM, XRD, EBSD, TEM, chemical dissolution analysis and tensile tests were carried out, and the influence of annealing process on the microstructure, mechanical properties and precipitation of annealed sheet was also explained. With the increase of nitrogen content, the phase transformation temperature decreases, the hardness increases and the recrystallization temperature increases. The microstructures of 20N steel and 150N steel annealed at different annealing temperatures are composed of ferrite and cementite distributed in chains. At the same annealing temperature, the recrystallization degree of 20N steel is higher, the {111} texture accounts for a larger proportion, and the grain size is larger. With the increase of annealing temperature, the yield strength and tensile strength show a downward trend, while the elongation shows an upward trend. Compared with 20N steel, the yield strength and tensile strength of the 150N annealed sheet are significantly improved, and the elongation is slightly reduced. The calculation results show that the mechanism of nitrogen improving the strength of tinplate is mainly solid solution strengthening, and the improvement effect of fine grain strengthening and precipitation strengthening is weak.

New insight for designing high-strength medium-entropy alloy with resistance to intermediate-temperature embrittlement by nitrogen-induced Ti-rich precipitation mechanism

Intermediate-temperature embrittlement is a common problem faced by many multi-component alloys. In this study, we propose the introduction of nitrogen into a lightweight TiVNb medium-entropy alloy to enhance solution strengthening and induce titanium segregation. Titanium-rich precipitates in turbine blade-like structures near the grain boundaries of a body-centred cubic solution matrix yield alloys that exhibit tensile ductility at intermediate temperatures. The titanium-rich precipitates dominantly have a face-centred cubic structure coupled with a small amount of hexagonal close-packed structure. The size of the titanium-rich phase increases with increasing nitrogen content from 0.5 % to 1.5 %, as does the alloy strength. The tensile yield strength of TiVNb-N1.5 reaches 1247 MPa at room temperature and 623 MPa at 800 °C, with a strain of 10 %. These values indicate that the prepared alloy overcomes the ultra-low strain of the base alloy at intermediate temperatures. By combining the MRS-Swap algorithm with the density functional theory, the formation mechanism of Ti-rich phases is deduced. This study further elucidates the types and pathways of interstitial elements that can induce FCC-Ti formation.

Investigation of Sulfur Influence on the Atomization of Stainless Steels

In this study, the alloying of stainless steels with various sulfur contents is investigated to obtain steel powders with significantly reduced mean diameters without changing the operational parameters of the atomizing unit. The steels are produced in a VIM12 furnace and atomized on a VIGA‐1B setup with high‐pressure argon. The desired reduction in the mean diameter is attributed to the decrease in surface tension with increasing sulfur content, which is in good agreement with previous findings. A transition from a positive to a negative thermal gradient of the surface tension is observed, along with a shift to higher temperatures with increasing sulphur concentration. In addition, the chemical assessment of the powders reveals a lower evaporation of manganese and a reduced increase in nitrogen content with increasing sulfur content. The sphericity and flowability are not affected by the addition of sulfur. Viscosity and density measurements are also conducted to characterize the steels thoroughly. Scanning electron microscopy reveals the presence of manganese sulfide, which was submicron in size and well distributed. Iron sulfides, mostly attributed to hot shortness, were not observed, which was also confirmed by thermodynamic modeling using Thermo‐Calc software.

Impact of Glow-Discharge Nitriding Technology on the Properties of 3D-Printed Grade 2 Titanium Alloy.

This study presents a comparative analysis of the corrosion resistance of nitrided layers on conventional Grade 2 titanium alloy and those produced by direct metal laser sintering (DMLS). Low-temperature glow-discharge nitriding of the tested materials was carried out using conventional glow-discharge nitriding (so-called nitriding at the cathode potential-TiN/CP) and with the use of an "active screen" (nitriding at the plasma potential-TiN/PP). The TiN + Ti2N + Ti(N) layers were characterized by their microstructure, nanohardness profile distribution, surface topography, and corrosion resistance. The reduction in the cathodic sputtering phenomenon in the process using the active screen allowed the creation of surface layers that retained the topography of the base material. The parameters of the glow-discharge treatment led to grain growth in the printed substrates. This did not adversely affect corrosion resistance. The corrosion resistance of nitrided layers on the printed titanium alloy is only slightly lower than that of layers on the conventional Grade 2 alloy. Iron precipitates at grain boundaries facilitate increased nitrogen diffusion, resulting in reduced nitrogen concentration in the surface layer, slight changes in corrosion potential values, and increased nitrogen concentration in the Ti(N) diffusion layer.

Microstructural evolution and formation of defect complexes in diamond films by nitrogen-containing plasma

Abstract The morphology and crystalline quality of polycrystalline diamond samples were studied by systematically varying the flowrate of nitrogen gas in the microwave plasma. A slight improvement in both crystallite size and crystalline quality is observed for a low concentration of 0.5 sccm nitrogen. With a further increase in nitrogen concentration, diamond switches from micro-crystalline (MCD) to nanocrystalline (NCD) with a nitrogen flow of 2.5 sccm (10% of methane concentration). The surface roughness of the sample is found to depend strongly on the crystallite size of the sample. Extensive spectroscopic studies have been done to understand the presence and formation of different defect complexes in diamond. The presence of nitrogen-containing defect complexes has been studied thoroughly and their concentration has been found to be limited by the solubility limit rather than the availability of reactants in the gas environment. In contrast, the effect these complexes have on the strain of the diamond film is found to be negligible. Optical emission spectroscopy (OES) of the plasma reveals the presence of C2 dimers as well as C-N radicals. However, they have little role in modifying diamond grain morphology or crystalline quality.

Nitrogen-rich sulfur-containing heterocyclic adsorbents for effective selective adsorption of Au(III)/Pd(II)/Pt(IV)

Recovering precious metals from secondary resources has elicited considerable attention, and exploring an efficient adsorbent is a challenge. In this work, we have specifically tailored three highly effective adsorbents (THDA@PEI, DCTA@PEI and DCTD@PEI) by crosslinking PEI with sulfur-containing heterocyclic cross-linking agents (2,5-thiophenedicarboxaldehyde, 2,4-dichlorothiazole and 3,4-dichloro-1,2,5-thiadiazole) for recovery of Au(III), Pd(II), and Pt(IV). These agents are distinguished by a range of nitrogen atom counts that extend from zero to two, offering a foundation for exploring the correlation between their molecular structure and adsorption performance. THDA@PEI, DCTA@PEI, and DCTD@PEI exhibit remarkable adsorption capacities for Au(III), Pd(II), and Pt(IV), with values reaching up to 2169, 2240, and 2536 mg/g for Au(III), 771, 886, and 846 mg/g for Pd(II), and 832, 1021, and 887 mg/g for Pt(IV), respectively. Among the three materials, DCTD@PEI stands out with a broader pH applicability range for both gold (pH 2 to 9) and platinum (pH 1 to 11) adsorption and exhibits a more rapid adsorption rate for Au and Pd. The adsorption processes of the three adsorbents on precious metals are spontaneous and entropy-increasing processes. Increasing the adsorption temperature could improve the adsorption performance of the three adsorbents, except for Pd adsorption by DCTD@PEI. All of the three adsorbents exhibit good selectivity and reusability for Au, Pd, and Pt, with DCTA@PEI being the most outstanding. It is observed that an increase in nitrogen content in the adsorbents correlates positively with the improvement of key performance indicators, including a wider pH range, higher adsorption capacity, faster kinetics, better selectivity, and enhanced reusability, while the substituent positions of crosslinking agents also have a strong impact on the adsorption performance, especially for Pd and Pt.

Hydrogen blending with natural gas for combustion efficiency improvement toward decarbonisation of power plants

Abstract The 12th Malaysia Plan highlighted Malaysia’s commitment to reduce Greenhouse Gas (GHG) emissions by 45% based on Gross Domestic Product (GDP) in 2030 and reach net zero by 2050. To achieve this target, Malaysia has to decarbonise the energy sector as it is the primary emission source, contributing up to 75% of GHG emissions in Malaysia. Hydrogen fuel is getting much attention globally, and it has been said that it can be a new renewable energy source to replace fossil fuels. Hydrogen combustion is clean and only produces water and energy. However, several studies have identified that hydrogen combustion could produce NOx, which is more harmful to the environment than CO2. Studies on hydrogen application in the energy sector in Malaysia are limited, and the implementation of total hydrogen fuel in power plants may not happen shortly. Hence, a fundamental study was proposed on co-firing hydrogen and natural gas fuel. This study aimed to examine co-firing characteristics such as temperature, pressure, and air-to-fuel ratio on GHG emission and energy release to find the optimum natural gas-to-hydrogen ratio. The model was developed using Aspen Plus, and hydrogen-natural gas blend percentages varied from 0% to 30%. The findings showed that increased operating temperature led to higher NOx formation, while varying pressures did not impact the CO2 and NOx formation. The pure natural gas combustion system was more sensitive towards air-to-fuel ratio changes, and an increase in air-to-fuel ratio to 1.5 led to 160% higher NOx formation due to an increase in nitrogen content. The combustion of the hydrogen blend led to lower CO2 formation but higher NOx formation. Lastly, the energy released by the hydrogen blending system was lower due to the formation of water that absorbed the heat released by the combustion.

Manure-derived black soldier fly frass enhanced the growth of chilli plants (Capsicum annuum L.) and altered rhizosphere bacterial community

Sustainable manure management is crucial for minimising environmental impacts as the livestock industry expands to meet the increasing demand for protein. Black soldier fly (Hermetia illucens L.) larvae (BSFL) farming is an emerging waste management method that efficiently processes large volumes of organic waste, including manure, to produce valuable protein, oil and chitin products. Frass, a nutrient-rich by-product of black soldier fly farming, has potential as an organic fertiliser. However, research has primarily focused on frass derived from food waste, with little exploration of manure-derived BSFL frass. This study aimed to determine whether frass derived from manure could enhance the growth of chilli (Capsicum annuum L.) over 14 weeks under controlled glasshouse conditions. The impacts of manure-derived BSFL frass on soil properties and soil bacterial communities were characterised. The results indicated that a 0.6 % w/w application rate yielded the highest chilli plant biomass, with reduced growth observed at higher rates. The enhanced growth at optimal manure-derived BSFL frass application rates was due to increased nitrogen content, whereas reduced growth at higher rates was likely caused by phytotoxicity from not completely decomposed frass. Soil microbial biomass carbon and nitrogen also increased with manure-derived BSFL frass, implying microbial carbon and nitrogen immobilisation. Additionally, the changes in pH and nutrients due to manure-derived BSFL frass caused shifts in the bacterial community in the chilli plant rhizosphere, enriching the relative abundance of bacteria with potential growth-promoting properties. This study highlights the potential of integrating manure into black soldier fly waste management processes, demonstrating that manure-derived BSFL frass can be used as an organic fertiliser with circular economy benefits.

Effect of Fe2O3 addition on synthesis of diamond single crystal under high-pressure and high-temperature conditions

The influence of Fe2O3 addition on the growth characteristics of synthetic diamonds under high-temperature and high-pressure conditions was systematically investigated in this work. Utilizing Fe2O3 as an oxygen source within the Fe-Ni-C-O system, oxygen-containing diamond single crystals were synthesized. The role of the oxygen atoms during the growth of large-sized diamonds with the {111} face as the growth surface was also analyzed. In addition, the morphology, growth rate, internal nitrogen content, and crystal quality of the crystals were examined. From our analysis, it was demonstrated that an increase in Fe2O3 addition leads to a reduction in the size of the synthetic crystals and a gradual decrease in the growth rate. The diamonds with complete crystal forms exhibited no significant change in color, and all appeared yellow. When the addition exceeded a threshold, cracks appeared around the seed crystal at about 0.3 mm, resulting in a cracked crystal phenomenon. A further increase in the Fe2O3 addition resulted in the skeleton crystal, and the crystal color turned black. Fourier Transform Infrared Spectroscopy (FTIR) measurements were also conducted, indicating that the introduction of oxygen atoms increases the nitrogen content in the crystals, which in turn aggregates in the form of C-centered nitrogen. The Raman spectroscopy results showed that as Fe2O3 addition in the crystals increases, more impurities are introduced, leading to an increase in the diamond stress and a shift in the diamond Raman peak, along with an increase in the full width at half maximum. The photoluminescence (PL) characterization results indicated that with the increase of the Fe2O3 addition, the intensity of the photoluminescence peaks of NV− centers and W8 centers was enhanced, which is related to the increase in the internal C-centered nitrogen content of the crystals. From the acquired results, it was proven that Fe2O3 addition has a significant impact on the synthesis of diamond single crystals. Our work provides valuable pieces of experimental evidence for exploring the formation mechanism of natural diamonds.

Non-destructive determination of volatile compounds and prediction of amino acid nitrogen during sufu fermentation via electronic nose in combination with machine learning approaches

Electronic nose along with different machine learning approaches was tested as tool to predict degree of sufu fermentation, with amino acid nitrogen content as marker. Consistent increase in E-nose signal values and amino acid nitrogen content were noted with fermentation time. The number of volatile compounds in sufu increased from 19 to 61 upon fermentation, with 46 compounds identified as major aroma contributors. Among them, acetone, ethyl palmitate and indole demonstrated strong correlations with amino acid nitrogen content. Three prediction models, i.e., partial least-squares regression, support vector machine, and artificial neural network, were tested for abilities to predict amino acid nitrogen content. All models were capable of quantitatively predicting the content of amino acid nitrogen, with ANN-based model demonstrating the highest prediction accuracy (RP2 = 0.968, RMSE = 5.49 × 10−8). Electronic nose along with appropriate prediction model is noted as a promising tool for evaluating the degree of sufu fermentation.

Disentangling the contributions of anthropogenic nutrient input and physical forcing to long-term deoxygenation off the Pearl River Estuary, China

Deoxygenation in estuarine and coastal waters worldwide has been largely attributed to the increasing anthropogenic nutrient input, whereas the contribution by long-term (decadal) changes in physical forcing is less investigated. This study aims to disentangle the impacts of three-decade changes in summer river nutrient concentration and physical forcing on the deoxygenation off a large eutrophic estuary, the Pearl River Estuary (PRE) in China. Using a coupled physical-biogeochemical model, we reproduce the observed summer oxygen conditions under the historical (the 1990s) and present (the 2020s) status of river nutrient concentration, freshwater discharge, and wind forcing. We show that the bottom hypoxic (dissolved oxygen < 2 mg/L) area off the PRE in the 2020s has increased by 73 % relative to the 1990s. The expansion is a result of the increased bottom water oxygen consumption outweighing the enhanced vertical oxygen supply, with the former driven by the sharp increase in inorganic nitrogen and phosphorus concentrations (160 %) and the latter caused by the decadal decline in both freshwater discharge (38 %) and wind speed (12.5 %) in summer. Model experiments suggest that if the observed changes in physical forcing had not occurred, the dramatic increase in anthropogenic nutrient concentrations from the 1990s to 2020s could have led to a much greater expansion of hypoxic area (249 %). On the contrary, the decadal decrease in summer freshwater discharge alone (while keeping the nutrient loading the same as in the 1990s) almost eliminates hypoxia off the PRE by weakening water column stratification and limiting the offshore spread of nutrients and organic matter, whereas the declined wind speed increases the hypoxic area by 247 % mainly through enhancing water column stability. Our results reveal that long-term changes in physical forcing are confounding the effects of anthropogenic nutrient input on deoxygenation, underlining the need to consider regional forcing changes in nutrient management to meet water quality goals.

Companion interference and symbiotic matching phenomenon occurred in saline-alkali habitats

Salinization has emerged as a worldwide concern hampering the progression of agriculture and husbandry. Arbuscular mycorrhizal (AM) fungi, which abundantly distributed in the Songnen Plain, was considered to possess great potential for combating salinity. To elucidate the relationship between AM fungal community and saline-alkali ecological remediation, a 70-days pot experiment, with the soil in the late succession stage of Songnen saline-alkali habitat was taken as substrate, the dominant plant in the latter as research object, and the rhizosphere soil from three stages as inoculants, was conducted. Simultaneously, Chloris virgate was cultivated to ascertain the accompanying role on mycorrhizal effects and soil improvement. The results revealed that AM fungi effectively regulated the botanical morphogenesis, photosynthesis, osmotic concentration, and antioxidant enzymatic activity under saline-alkali conditions. Specifically, the net photosynthetic rate increased by 1.11–2.44 μmol·(m2)−1·s−1, and the total root length grew by 41.15–148.98 cm after inoculation. Furthermore, the soil salinization and nutrient sequestration were modulated by AM fungi, and that leaded to a notable reduction in soil pH by 0.3 %-1.64 % and an increase in nitrogen content by 52.17 %-118.84 %. In a comprehensive assessment, the utmost ecological advantage appeared in the group inoculated AM fungi procured from the identical stage as the host, with a peak mycorrhizal dependency of 2.93. Additionally, despite enhancing salinization restoration compared to the non-companion group, the associated plants reduced the mycorrhizal dependency of neighbour by a range of 27.04–51.46 %, and significantly decreased the dry weight by 0.09–0.28 g. These results confirmed the occurrence of symbiotic matching phenomenon in saline-alkali habitats and suggested that the mechanism should be considered as utilizing AM fungi for ecological restoration. However, the introduction of companion should be cautious due to their complex effects.

The Use of Compost and Arbuscular Mycorrhizal Fungi and Their Combination to Improve Tomato Tolerance to Salt Stress.

Salinity poses a significant challenge to tomato plant development and metabolism. This study explores the use of biostimulants as eco-friendly strategies to enhance tomato plant tolerance to salinity. Conducted in a greenhouse, the research focuses on the Solanum lycopersicum L. behavior under saline conditions. Tomato seeds were treated with arbuscular mycorrhizal fungi (AMF), compost, and their combination under both non-saline and saline conditions (0 and 150 mM NaCl). Plant height, number of flowers and fruits, shoot fresh weight, and root dry weight were negatively impacted by salt stress. The supplementation with compost affected the colonization of AMF, but the application of stress had no effect on this trait. However, the use of compost and AMF separately or in combination showed positive effects on the measured parameters. At the physiological level, compost played a beneficial role in increasing photosynthetic efficiency, whether or not plants were subjected to salinity. In addition, the application of these biostimulants led to an increase in nitrogen content in the plants, irrespective of the stress conditions. AMF and compost, applied alone or in combination, showed positive effects on photosynthetic pigment concentrations and protein content. Under salt stress, characterized by an increase in lipid peroxidation and H2O2 content, the application of these biostimulants succeeded in reducing both these parameters in affected plants through exhibiting an increase in antioxidant enzyme activity. In conclusion, incorporating compost, AMF, or their combined application emerges as a promising approach to alleviate the detrimental impacts of salt stress on both plant performances. These findings indicate optimistic possibilities for advancing sustainable and resilient agricultural practices.

LiNO3-Based Deep Eutectic Mixtures Comprising Organic Additives As Promising Electrolytes for Stable Li-Metal Batteries

Deep eutectic electrolytes have emerged as a novel energy storage solution, presenting distinct advantages over traditional ionic liquid electrolytes. These advantages include a high ion concentration, cost-effective, wide electrochemical window, and inherent safety.In this study LiNO3, which is valuable additive but difficult to melt in carbonate electrolytes, was used as the lithium salt for a deep eutectic solvent (DES) electrolyte. LiNO3 demonstrated its capability to form deep eutectic solutions with N-methyl acetamide (N-MAc) and Methyl carbamate (MCB) in a 1:4 molar ratio. An suitable additives was introduced to study the effect on electrochemical behaviors.Li//Cu asymmetric cells was utilized to evaluate the coulombic efficiency (CE) of lithium plating/stripping with various electrolytes. The lithium plating/stripping stability is investigated by evaluating the cycle life of Li//Li symmetric cells. The electrochemical window is determined by the Li//Pt asymmetric cells underwent linear sweep voltammetry (LSV). A commercial LiMn2O4 (LMO) is used as cathode to assemble the Li//LMO lithium-metal cells to evaluate cycle stability, rate capabilities, and AC impedance. The physical properties of the electrolytes underwent systematic analysis using Fourier Transform Infrared Spectroscopy (FT-IR), Raman spectroscopy, Differential Scanning Calorimetry (DSC), conductivity, and viscosity measurements. Post-analysis of Li//Cu asymmetric cells revealed additive-induced differences. SEM and EDS analyses unveiled elemental variations on copper foil, and X-ray Photoelectron Spectroscopy (XPS) provided surface insights.For the first system, the LiNO3 and N-MAc electrolyte exhibited an extended plating/stripping cycle life of reaching 450 hours with the addition of 10 wt% VC in Li//Li symmetrical cell. Addition VC as additive significantly improved conductivity and viscosity. Surprisingly, in Li//Cu asymmetrical cells, 5 wt% VC demonstrated better stability. The Li//Pt asymmetrical cells shows the electrolyte decomposition is occurs at 5V, which is high compared to organic electrolyte. In Li//LMO lithium-metal cells, an impressive 2000 cycles were achieved, with a remarkable 80% capacity retention in rate capabilities testing at high current density and sustained cycling up to 1000 cycles at lower current density. Raman and FT-IR analysis revealed blue shifts in characteristic peaks of C=O and N-H, indicating lithium ions from LiNO3 indeed interact with N-MAc. SEM and EDS testing confirmed that the presence or absence of VC influenced lithium-ion deposition. In the presence of VC, there was a notable increase in oxygen, nitrogen, and carbon content, imply that the enhanced lithium-ion deposition and dissolution capabilities.For the second system, the LiNO3 and MCB electrolyte system, 8 wt% FEC addition in Li//Li symmetrical cells resulted in a cycle life of only 60 hours. Li//Cu asymmetrical cells showed improved lithium-ion deposition and dissolution with FEC for 12 cycled. Li//Pt asymmetrical cells displayed a decomposition at 4.6V. Li//LMO lithium-metal cells with 5 wt% FEC exhibited stability, cycling up to 120 cycles. Raman and FT-IR analysis indicated blue shifts in the characteristic peaks of C=O and N-H stretching vibrations, signifying deep eutectic interactions between LiNO3 and MCB. Red shifts were observed in N-H bending vibrations. FEC addition improved conductivity and viscosity. SEM and EDS testing demonstrated that the presence or absence of FEC affected lithium-ion deposition. In the presence of FEC, components such as oxygen, nitrogen, carbon, and fluorine were detected, with fluorine constituting a significant 26.70%, indicating improved lithium-ion deposition and dissolution capabilities. XPS peaks corresponding to Li 1s, F 1s, and N 1s, affirming the efficacy of FEC in promoting lithium-ion deposition.In conclusion, the deep eutectic electrolyte formed by LiNO3 and N-MAc in a 1:4 molar ratio demonstrated superior stability. Additives proved effective in improving electrolyte properties without compromising coordination. Both electrolytes exhibited comparable cycle life, emphasizing their suitability for positive electrode materials like LMO. Moreover, sustained high current density in rate capabilities testing further highlighted their potential for practical applications. Figure 1