Increase In Nitrogen Content Research Articles

A Spray Foliar Containing Methylobacterium symbioticum Did Not Increase Nitrogen Concentration in Leaves or Olive Yield Across Three Rainfed Olive Orchards

Biological nitrogen (N) fixation has been advocated in agricultural fields due to being considered a more sustainable way to introduce N into agrosystems than industrial N fertilizers. In this study, a foliar spray inoculant containing the microorganism Methylobacterium symbioticum was applied. This microorganism is known for fixing N in the phyllosphere, regardless of the cultivated species. This study was conducted in three rainfed olive orchards over three years. In two orchards managed according to European Union (EU) integrated production rules, the experiment was organized as a factorial design with inoculant (applied at two levels, yes and no) and N fertilization (applied to the soil at three levels, 0, 40, and 80 kg ha−1 of N). The third trial, managed according to EU organic farming rules, was organized in a completely randomized design with three treatments: with (yes) and without (no) inoculant and with a treatment involving a seaweed extract, also for foliar application. The microbiological inoculant did not consistently influence olive yield or N concentration in leaves across the three trials. Conversely, N application to the soil significantly influenced N concentration in leaves and olive yield. In one of the trials, in the third year of the study, soil N application (80 kg ha−1) resulted in an olive yield of ~eight times higher than the unfertilized control treatment. The seaweed extract also did not lead to significant differences in leaf mineral composition or olive yield compared with the other treatments. These findings from the on-farm research highlight the importance of accurately determining the conditions under which commercial products can deliver effective results. It is crucial to acknowledge that these products involve expenses not only in their acquisition but also in their application.

Adsorption of Tetracycline in Composite-polluted Water by Biochar from Industrial Production

Compared to the laboratory preparation of biochar, there is less research on the adsorption of antibiotics by industrial production of biochar in water. In this study, three types of industrial production biochar （peanut shell biochar, sludge biochar, and perishable waste biochar） were selected, and their adsorption performance for tetracycline in composite-polluted water was systematically studied. The results indicated that the Freundlich equation could well fit the adsorption isotherms of the three types of biochar for tetracycline. At medium to high concentrations （>10 mg·L-1）, the order of adsorption capacity of biochar for tetracycline was： perishable waste biochar > sludge biochar > peanut shell biochar. The aromaticity, hydrophobicity, and specific surface area of peanut shell biochar had important effects on its adsorption of tetracycline. The possible main adsorption mechanisms were π-π interaction, hydrophobicity, and pore filling. The specific surface area and pore volume of sludge biochar had a significant impact on its adsorption of tetracycline, and its possible main mechanisms included pore filling, surface complexation, and hydrogen bonding. The soluble organic carbon components and ash content of perishable waste biochar played a dominant role in its adsorption, with distribution being the main adsorption mechanism, followed by cation-π interaction and surface complexation. The effect of coexisting pollutants on the adsorption of tetracycline by biochar varied with the type of biochar. With the increase in ion strength and ammonia nitrogen concentration in the water, the adsorption capacity of peanut shell biochar for tetracycline showed a slight upward trend overall, whereas sludge biochar showed a slight downward trend. The adsorption of tetracycline on perishable waste biochar was not affected by ionic strength and ammonia nitrogen. Coexisting phosphates significantly reduced the adsorption efficiency of biochar for tetracycline, while coexisting aerobic organic compounds had no significant effect on the adsorption. The adsorption of tetracycline in water by sludge biochar and perishable waste biochar had good recyclable regeneration ability. The results of this study provide a reliable scientific basis and theoretical support for the engineering application of biochar in removing antibiotics from water.

High-concentration diamond nitrogen vacancy color center fabricated by microwave plasma chemical vapor deposition and its properties

Diamond nitrogen vacancy (NV) color centers have good stability at room temperature and long electron spin coherence time, and can be manipulated by lasers and microwaves, thereby becoming the most promising structure in the field of quantum detection. Within a certain range, the higher the concentration of NV color centers, the higher the sensitivity of detecting physical quantities is. Therefore, it is necessary to dope sufficient nitrogen atoms into diamond single crystals to form high-concentration NV color centers. In this study, diamond single crystals with different nitrogen content are prepared by microwave plasma chemical vapor deposition (MPCVD) to construct high-concentration NV color centers. By doping different amounts of nitrogen atoms into the precursor gas, many problems encountered during long-time growth of diamond single crystals under high nitrogen conditions are solved. Diamond single crystals with nitrogen content of about 0.205, 5, 8, 11, 15, 36, and 54 ppm (1ppm –10<sup>–6</sup>) are prepared. As the nitrogen content increases, the width of the step flow on the surface of the diamond single crystal gradually widens, eventually the step flow gradually disappears and the surface becomes smooth. Under the experimental conditions in this study, it is preliminarily determined that the average ratio of the nitrogen content in the precursor gas to the nitrogen atom content introduced into the diamond single crystal lattice is about 11. Fourier transform infrared spectroscopy shows that as the nitrogen content inside the CVD diamond single crystal increases, the density of vacancy defects also increases. Therefore, the color of CVD high nitrogen diamond single crystals ranges from light brown to brownish black. Compared with HPHT diamond single crystal, the CVD high nitrogen diamond single crystal has a weak intensity of absorption peak at 1130 cm<sup>–1</sup> and no absorption peak at 1280 cm<sup>–1</sup>. Three obvious nitrogen-related absorption peaks at 1371, 1353, and 1332 cm<sup>–1</sup> of the CVD diamond single crystal are displayed. Nitrogen atoms mainly exist in the form of aggregated nitrogen and single substitutional N<sup>+</sup> in diamond single crystals, rather than in the form of C-defect. The PL spectrum results show that defects such as vacancies inside the diamond single crystal with nitrogen content of 54 ppm are significantly increased after electron irradiation, leading to a remarkable increase in the concentration of NV color centers. The magnetic detection performance of the NV color center material after irradiation is verified, and the fluorescence intensity is uniformly distributed in the sample surface. The diamond single crystal with nitrogen content of 54 ppm has good microwave spin manipulation, and its longitudinal relaxation time is about 3.37 ms.

The Nitrogen Fixation Characteristics of Terrestrial Nitrogen-Fixing Cyanobacteria and Their Role in Promoting Rice Growth

Cyanobacteria, ubiquitous phototrophic prokaryotes, can enhance soil fertility and crop productivity by promoting biological nitrogen fixation, phosphate dissolution, and mineral release. In this study, five nitrogen-fixing cyanobacteria were isolated and purified from paddy soil in Jilin Province. The effects of nitrogen-fixing cyanobacteria on soil fertility and rice seedling growth were examined through a pot experiment to clarify their growth and nitrogen-fixing characteristics. The results showed that the application of nitrogen-fixing cyanobacteria led to a significant increase in soil nitrogen content. GD2 and GD8 have the highest nitrogenase activity, at 75.33 U·mg−1 and 50.34 U·mg−1, respectively. It also enhanced the activities of urease, sucrase, phosphatase, and catalase in rice soil. In addition, it significantly promoted root development and plant height in rice plants. The total number of microorganisms in rice soil increased by 133–366%. Remarkably, the Desmonostoc muscorum GD2 strain was found to exhibit higher growth state indicators, including the growth curve, chlorophyll content, carbon and nitrogen content, and biomass accumulation, compared to other algae strains. The total nitrogen content of rice leaves treated with GD2 increased by 48.73%, and the soluble protein content increased by 52.89%. GD2 has great potential as an excellent nitrogen-fixing cyanobacteria inoculant for rice, suitable for agricultural production. In conclusion, the application of these nitrogen-fixing cyanobacteria significantly increased soil nitrogen levels and activated key enzyme activities involved in plant nitrogen metabolism. Moreover, it improved nitrogen utilization rates and promoted plant growth.

Impact of Microbial Inoculants and Additives on Rice Straw Composting

Rice straw is a lignocellulosic waste, which is recalcitrant in nature and contains high lignin content. A recalcitrant property provides resistance from natural degradation thus, decomposition of lignocellulosic waste becomes a difficult task. Composting of rice straw is a sustainable practice that benefits environment, agriculture and economy by turning the agricultural waste into valuable resource that might otherwise be burnt or left to decompose inefficiently. This study investigated the effect of different additives on composting of rice straw with combination of microbial consortium (bacteria and fungi). The addition of organic supplements (i.e., biogas slurry, rock phosphate and green waste) significantly raised the initial temperature of compost treatments, and microbial consortium accelerated lignocellulose decomposition during composting. Organic carbon was found to decrease in all the treatments with the progression of decomposition and least i.e. 29.50% was observed in treatment T5 [rice straw + biogas slurry + rock phosphate + green waste (4:1:1:1) + microbial consortium] at the end of composting which had initial organic carbon of 44.80%. A comparative increase in nitrogen content was observed in all the treatments with the commencement of decomposition. After 90 days of composting, treatment T5 contained the highest total nitrogen (1.36%) ultimately led to decrease in C/N ratio. Among all the treatments, T5 showed noticeably increased degradation rate of cellulose, hemicellulose and lignin content. Moreover, humic acid in compost from T5 was also found to be highest (108 mg g-1). The use of additives seems to improve the stability of rice straw compost as well as use of microbial consortium was found to reduce the time of decomposition of substrates. The research findings will be helpful in optimizing the use of organic waste materials by turning them into nutrient rich compost more quickly and effectively.

The Combined Effects of Salt and Nitrogen Addition on the Chlorophyll Fluorescence, Antioxidant System, and Leaf Stoichiometry of Torreya grandis Sexes

Previous studies have shown that there are significant sexual differences in the physiological responses of Torreya grandis to environmental stress. However, little is known about its sex-specific differences in response to salt stress against the background of nitrogen (N) deposition. In this experiment, two-year-old male and female T. grandis seedlings were used as experimental materials and exposed to moderate salt conditions and different N levels to study the effects of nitrogen addition and salt stress on the chlorophyll content, chlorophyll fluorescence parameters, antioxidant system, and leaf stoichiometry of T. grandis seedlings. With the increase in nitrogen content, the contents of proline, malondialdehyde, superoxide anion, and H2O2 in the leaves of T. grandis seedlings under salt conditions gradually increased. The contents of these four metabolites in the leaves of male T. grandis seedlings were almost all higher than those of the female ones. Compared with the control group, the contents of enzymatic and non-enzymatic antioxidants increased under N addition treatments, especially for the low and moderate N addition groups. The results showed that moderate concentrations of N addition can mitigate the damage caused by salt, while high concentrations of nitrogen do not. Under conditions of salt and nitrogen addition, female T. grandis seedlings outperformed male ones, as evidenced by their higher photosynthetic pigment content, enhanced antioxidant enzyme activity, reduced accumulation of intracellular cytotoxic metabolites, and higher carbon and nitrogen content in their leaves compared to those of male seedlings. The findings of this research will contribute to our understanding and offer a theoretical foundation for the cultivation of T. grandis seedlings in environments with nitrogen deposition and salinization.

Growth, Quality, and Nitrogen Metabolism of Medicago sativa Under Continuous Light from Red-Blue-Green LEDs Responded Better to High Nitrogen Concentrations than Under Red-Blue LEDs.

Alfalfa is a widely grown forage with a high crude protein content. Clarifying the interactions between light quality and nitrogen level on yield and nitrogen metabolism can purposely improve alfalfa productivity in plant factories with artificial light (PFAL). In this study, the growth, quality, and nitrogen metabolism of alfalfa grown in PFAL were investigated using three nitrate-nitrogen concentrations (10, 15, and 20 mM, labeled as N10, N15, and N20) and continuous light (CL) with two light qualities (red-blue and red-blue-green light, labeled as RB-C and RBG-C). The results showed that the adaptation performance of alfalfa to nitrogen concentrations differed under red-blue and red-blue-green CL. Plant height, stem diameter, leaf area, yield, Chl a + b, Chl a, Chl b, crude protein contents, and NiR activity under the RB-CN15 treatment were significantly higher than RB-CN10 and RB-CN20 treatments. The RB-CN20 treatment showed morphological damage, such as plant dwarfing and leaf chlorosis, and physiological damage, including the accumulation of proline, H2O2, and MDA. However, the difference was that under red-blue-green CL, the leaf area, yield, and Chl a + b, carotenoid, nitrate, and glutamate contents under RBG-CN20 treatment were significantly higher than in the RBG-CN10 and RBG-CN15 treatments. Meanwhile, the contents of soluble sugar, starch, and cysteine were significantly lower. However, the crude protein content reached 21.15 mg·g-1. The fresh yield, dry yield, stomatal conductance, leaf area, plant height, stem diameter, crude protein, GS, and free amino acids of alfalfa were positively correlated with increased green light. In addition, with the increase in nitrogen concentration, photosynthetic capacity, NiR, and GOGAT activities increased, promoting growth and improving feeding value. The growth, yield, photosynthetic pigments, carbon, nitrogen substances, and enzyme activities of alfalfa were significantly affected by the interaction between nitrogen concentration and light quality, whereas leaf/stem ratio and DPPH had no effect. In conclusion, RB-CN15 and RBG-CN20 are suitable for the production of alfalfa in PFAL, and green light can increase the threshold for the nitrogen concentration adaptation of alfalfa.

Prediction of CO2 adsorption of biochar under KOH activation via machine learning

To effectively increase the CO2 adsorption capacity of biochar, the activation process is often an indispensable link. However, the introduction of an activation process poses challenges in clarifying the relationship between the characterization parameters of biochar, adsorption parameters, and CO2 adsorption capacity. Herein, a comprehensive dataset encompassing the CO2 adsorption data of KOH-activated biochar using a “two-sep method” was compiled. Subsequently, ridge regression, multi-layer perceptron, and random forest models were employed to predict its CO2 adsorption performance. To comprehensively explore the effects of activation conditions, physicochemical properties and adsorption parameters on CO2 adsorption capacities, partial dependence via Shapley additive explanation (SHAP) values analysis was conducted. The results demonstrate that the multilayer perceptron model exhibits the highest prediction accuracy with a test R2 value of 0.961. Additionally, it was found that the CO2 adsorption capacity of activated biochar is primarily determined by micropores and nitrogen-containing groups rather than total pore volume at low adsorption pressure (< 0.3 bar). Moreover, it increases significantly with decreasing average pore size, increasing pore volume, and increasing nitrogen content at low adsorption temperatures (< 20 °C). When the ratio of KOH to biochar is in the range of 1–2 and the activation temperature is ∼ 700 °C, activated biochar with high CO2 adsorption performance can be obtained. This study may provide valuable insights for the application of activated biochar in CO2 adsorption.

Effects of biochar-loaded microbial agent in regulating nitrogen transformation and integration into humification for straw composting

Exogenous additives can impact organic matter transformation in composting, but their effects on nitrogen conversion and humification in straw composting require clarification. This study investigated how rice husk biochar-loaded microbial agent (RM) affects nitrogen transformation and humification during straw composting. Results showed that the addition of RM enhanced ammonia oxidation and assimilation during composting, leading to a 10.32%–22.27% increase in total nitrogen content. Furthermore, the RM treatment enriched nitrogen-converting microbes such as Longispora and Coprinopsis, enhancing synergistic relationships among microbes, facilitating the accumulation of pivotal nitrogenous humus precursors (amino acid nitrogen), and promoting humus formation. This research not only guides reducing nitrogen loss during composting and elucidating the relationship between nitrogen transformation and humification but also contributes to enhancing bioconversion efficiency of agricultural waste to explore new ways of straw waste management.

Growth of Diamond on Si, SiC, Mo and Diamond Substrates for Heat Spreader, Optical Window, and Surface Graphitized Devices

Introduction Diamond, owing to its exceptional impact resistance, high thermal conductivity, broad-spectrum optical transparency, elevated breakdown field strength, and superior carrier mobility, finds widespread application in diverse fields such as high-power laser windows, efficient heat spreader, and high-performance semiconductor devices. Experimental 1. Heteroepitaxial Growth of Polycrystalline Diamond on Si, SiC, and Mo Substrates:In this part, substrates employed include double-side polished 4H-polytype SiC, (100) single-side polished single-crystal Si wafers, and Mo substrates. Ultrasonic grinding of substrates using diamond powder ethanol suspension to promote the dispersion of nucleation seeds, followed by sequential ultrasonic cleaning in acetone, ethanol, and deionized water.Subsequently, MPCVD was used for diamond growth, using hydrogen, methane, oxygen, and a mixture of hydrogen and nitrogen as reaction gases. Using different processes to produce efficient heat sinks and high-power laser windows. 2. Homoepitaxial Growth of Single-Crystal Diamond on Diamond Substrates:In the homoepitaxial growth process, (100) double-side polished single-crystal diamond substrates are utilized. No need for ultrasonic grinding steps, cleaning steps are the same as above. Then use MPCVD for homogeneous epitaxial growth of single-crystal diamond. 3. Investigation of Graphitized Surface Devices on Diamond:This study also investigated the graphitization devices on diamond surfaces. A high-temperature metal-catalyzed method is employed to promote surface graphitization of diamond. Firstly, polish and clean the diamond. Subsequently, a 300 nm thick nickel layer is deposited on the diamond surface. Rapid thermal annealing is then performed at 1300°C to form a highly conductive graphite layer. This process successfully prepares capacitor samples with a graphite-diamond-graphite three-layer structure. Results and Discussion 1. High-Power Laser Window Plates:The fabricated laser window plates utilize Si, SiC and Mo substrates, employing an ultra-low nitrogen growth process with a growth rate of approximately 3.7 µm/h. After double-sided polishing, the thickness reaches 1 mm. At room temperature, the transmittance at 10.6 µm wavelength approaches the theoretical maximum, reaching 67.9%. The overall thermal conductivity exceeds 1950 W/mK, approximating that of single-crystal diamond.Raman spectroscopy and XRD results indicate that the primary component is polycrystalline diamond with a (110) crystallographic orientation. Laser testing results demonstrate that these window plates possess a high laser-induced damage threshold with a peak energy of 60 J/cm2 and a peak power of 12 MW/mm2, capable of withstanding high-power CO2 laser output. 2. Heat Spreader:This study involves depositing diamond on Si and SiC substrates, forming diamond-based composite materials. This significantly improves the heat dissipation efficiency of the devices, bringing their performance closer to theoretical limits. The deposition process employs a low-nitrogen technique to balance growth rate and defect density, achieving a growth rate of approximately 5 µm/h.Raman spectroscopy and XRD results indicate that the primary component is polycrystalline diamond with a (110) crystallographic orientation. Although the increased nitrogen content results in lower optical transmittance compared to optical window plates, the grain size can be increased from 124 nm to 22 μm through production process adjustments, thereby enhancing thermal conductivity.Test results demonstrate that the thermal conductivity of the Si-diamond composite material reaches 450 W/mK,3 times that of single-crystal Si. The SiC-diamond composite material achieves a thermal conductivity of 500 W/mK,3.5 times that of SiC. 3. Single-Crystal Diamond:The transmittance and thermal conductivity of single-crystal diamond grown by homoepitaxial growth are superior to those of polycrystalline diamond. However, limitations in size and growth conditions restrict its large-scale application in heat spreaders and optical windows. Single-crystal diamond is more suitable for manufacturing semiconductor devices such as diamond capacitors, Schottky diodes, and hydrogen-terminated MOSFETs.The author has conducted research on doping of single-crystal diamond. Characterization through Raman spectroscopy, XRD, and TEM confirms that the primary component is single-crystal diamond with a (100) crystallographic orientation. The dislocation density is below 103/cm2, meeting the stringent requirements for semiconductor devices. 4. Graphite-Diamond-Graphite Capacitors:Utilizing prepared diamond, graphite-diamond-graphite capacitors were fabricated. Measurements using a semiconductor parameter analyzer revealed a high capacitance value of 4 nF. TCAD simulation indicated a breakdown voltage as high as 1100 V. This research explores a novel method for diamond capacitor fabrication. Conclusions Diamond heteroepitaxial grown on Si, SiC, and Mo substrates has prepared high-power laser windows with 67.9% optical transmittance at 10.6 μm wavelength, and composite materials with thermal conductivity enhanced to 3-3.5 times that of the original materials. Homoepitaxially grown diamond on single-crystal diamond substrates exhibits a dislocation density below 10³/cm², meeting the requirements for semiconductor device substrates. Furthermore, this research has developed a novel diamond capacitor fabrication technique, yielding capacitors with a capacitance of 4 nF and a breakdown voltage of 1100 V.

Melting simulations of high-entropy carbonitrides by deep learning potentials

The melting temperature is a crucial property of materials that determines their potential applications in different industrial fields. In this study, we used a deep neural network potential to describe the structure of high-entropy (TiZrTaHfNb)CxN1−x carbonitrides (HECN) in both solid and liquid states. This approach allows us to predict heating and cooling temperatures depending on the nitrogen content to determine the melting temperature and analyze structure changes from atomistic point of view. A steady increase in nitrogen content leads to increasing melting temperature, with a maximum approaching for 25% of nitrogen in the HECN. A careful analysis of pair correlations, together with calculations of entropy in the considered liquid phases of HECNs allows us to explain the origin of the nonlinear enhancement of the melting temperature with increasing nitrogen content. The maximum melting temperature of 3580 ± 30 K belongs to (TiZrTaHfNb)C0.75N0.25 composition. The improved melting behavior of high-entropy compounds by the addition of nitrogen provides a promising way towards modification of thermal properties of functional and constructional materials.

Boosting the catalytic performance of carbon nitrides for overall water splitting by tuning the C/N ratio: A theoretical investigation

We systematically study the catalytic activity of carbon nitride materials by controlling the carbon-to-nitrogen ratio and engineering their morphological structure. The electrocatalytic activities of five types of carbon nitrides with different C/N ratios— C4N, C3N, C2N, CN, and C3N4 — toward the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) are theoretically evaluated. The results show that the OER overpotential decreases as the nitrogen content increases, reaching its lowest value in CN. Our results highlight CN as a bifunctional electrocatalyst with acceptable performance with overpotentials of 0.76 and 0.05 V for OER and HER, respectively.

A two-pronged strategy to boost the capacitive deionization performance of nitrogen-doped porous carbon nanofiber membranes

Carbon-based capacitive deionization (CDI) systems are universally subject to the limited desalination capacity, due to the electrosorption characteristics and undesirable pore structures. Herein, a two-pronged strategy is proposed to boost the desalination performance of the electrospun carbon nanofibers (CNFs), where silicalite-1 nanoparticles as the internal porogen create mesopores and macropores, and layered zeolitic imidazolate framework (ZIF-L) leaves as the external carbon source provide micropores and mesopores. This combination results in the large surface area, well-developed graded pore structure, and increased nitrogen content of the core-shell polyacrylonitrile/silicalite-1@ZIF-L-derived CNFs (defined as PCNFs-SZ) electrode, which delivers a superior specific capacitance of 145.4 F g−1 in a neutral electrolyte. The symmetric CDI cell assembled by the self-supporting PCNFs-SZ membrane electrodes holds a prominent desalination capacity of 37.09 mg g−1 and a rapid salt removal rate of 10.36 mg g−1 min−1 at 1.2 V (initial NaCl concentration: 500 mg L−1), and demonstrates significant potential for real-world applications in the desalination and purification of reclaimed water. Furthermore, theory calculations confirm the enhanced Na+-capture capability of PCNFs-SZ. The present work highlights an effective and viable approach to enhance the desalination performance of carbon-based CDI cells.

Corrosion Properties of Weld Metal in 304 Stainless Steel for Food Grade Using GTAW with Various Types of Backing Gas

This study investigated the impact from nitrogen content in backing gases on the microstructure and corrosion resistance of food grade stainless steel weld metal. Three types of backing gases were employed: 100%Ar, 85%Ar+15%N2, and 100%N2. Statistical analysis using ANOVA revealed a significant effect from nitrogen content on the ferrite phase fraction within the weld metal microstructures (p-value = 3.5E-05), indicating a reduction in the ferrite phase with increasing nitrogen content. Moreover, increasing nitrogen content positively shifted the pitting corrosion potential, indicating enhanced corrosion resistance. Optical microscopy confirmed lower pit density in samples with nitrogen backing gas as compared with samples with argon backing gas. These findings underscore the crucial role of nitrogen content in backing gases at influencing microstructure and corrosion resistance in stainless steel weld metal, with higher nitrogen levels correlated with improved corrosion resistance.

Unravelling Coupled Hydrological and Geochemical Controls on Long-Term Nitrogen Enrichment in a Large River Basin.

Many groundwater and surface water bodies around the world show a puzzling and often steady increase in nitrogen (N) concentrations, despite a significant decline of agricultural N inputs. This study uses a combination of long-term hydrogeochemical and hydraulic monitoring, molecular characterization of dissolved organic matter (DOM), column experiment, and reactive transport modeling to unravel the processes controlling N-reactive transport and mass budgets under the impacts of dynamic hydrologic conditions at a field site in the central Yangtze River Basin. Our analysis shows that the desorption of ammonium (NH4+) from sediments via cation exchange reactions dominates N mobilization and aqueous N concentrations, while the mineralization of organic N compounds plays only a minor role. The reactive transport modeling results illustrate the important role of cation exchange reactions that are induced by temporary NH4+ input and cation concentration changes under the impact of both seasonal and long-term hydrologic variations. Historically, cation exchangers have acted as efficient storage devices and mitigated the impacts of high levels of NH4+ input. The NH4+ residing on cation exchanger sites later acts as a long-term N source to waters with the delayed desorption of sediment-bound NH4+ induced by the change of hydrologic conditions. Our results highlight the complex linkages between highly variable hydrologic conditions and NH4+ partitioning in near-surface, river-derived sediments.

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.

The first results of the study of large diamonds from industrial deposits of Yakutia

A representative amount of diamonds larger than 10,8 carats extracted from deposits of Yakutia during the separate ore processing of each kimberlite pipe has been studied for the first time. It is shown that according to such typomorphic characteristics of a diamond as habitus, nitrogen content and aggregation, hydrogen concentration in a diamond, it is possible to carry out a preliminary evaluation of the deposit to predict the presence of large and giant diamonds. It has been established that large diamonds from the deposits of the Daldyn-Alakitsky area have a wide variations of nitrogen impurity and its aggregations in comparison with diamonds from the Malobotuobinsky, Srednemarkhinsky areas. It is determined that the content of large diamonds in the pipes of Yakutia is inversely proportional to the number of rounded dodecahedroids. The most promising deposits for finding of large diamonds are those in which the majority of diamonds belong to one population – average nitrogen low-aggregated diamonds that were formed at a temperature of ~1100оC. According to the study of geological collections of diamonds, it is shown that in kimberlite pipes with an increased nitrogen content in diamonds, a raising in the proportion of large diamonds in the deposit is noted. On the contrary, according to the aggregation of nitrogen in diamonds, as a parameter of the post-growth history, there is a negative correlation with the content of large diamonds. Increased value concentrations of hydrogen in diamonds not only negatively affect the total diamond content of the deposit, but also generally control the decrease in the content of large diamonds.

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.

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 20 N steel and 150 N 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 20 N steel and 150 N steel annealed at different annealing temperatures are composed of ferrite and cementite distributed in chains. At the same annealing temperature, the recrystallization degree of 20 N 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 20 N steel, the yield strength and tensile strength of the 150 N 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.