Reduced Nitrogen Content Research Articles

Stress signaling, response, and adaptive mechanisms in submerged macrophytes under PFASs and warming exposure.

Heat stress disturbs cellular homeostasis and alters the fitness of individual organisms. However, it is unclear whether thermal perturbations exacerbate the toxic effects of per- and polyfluorinated alkyl substances (PFASs) on trophic endpoints in freshwater ecosystems. We conducted a mesocosm experiment to investigate the impact of warming and PFASs on the widespread submerged macrophytes (Hydrilla verticillata) at a molecular level. Quantitative and air flow-assisted ionization mass spectrometry imaging results showed that warming significantly increased the accumulation of PFOS (3.53L/kg) in the submerged leaf tissues. Accumulation of PFASs altered H. verticillata intracellular scavenging enzymes, an effect that may be exacerbated by 4°C warming. Warming and PFASs influenced photosynthesis, biological rhythms, and ecological stoichiometry, causing a decrease in metabolites linked to the tricarboxylic acid cycle and amino acid metabolism, which compromised nitrogen use efficiency (9.9%-30.4% reduction in nitrogen content, 0.8%-22.8% increase in C:N ratios). Additionally, metabolites are linked to the antioxidant system or cell wall components, with linoleic acid decreasing by 17.1%-82.8% and carbohydrate-related compounds dropping by 52.2%-89.0%. Our modeling analyses revealed that H. verticillata enriched with PFASs could pose secondary risks when consumed by herbivorous fish (Ctenopharyngodon idellus) under warming, potentially affecting food chain dynamics.

Numerical Simulation Study on the Stable Combustion of a 660 MW Supercritical Unit Boiler at Ultra-Low Load

To investigate the safe, stable, and economically viable operation of a boiler under ultra-low-load conditions during the deep peaking process of coal-fired units, a numerical simulation study was conducted on a 660 MW front- and rear-wall hedge cyclone burner boiler. The current research on low load conditions is limited to achieving stable combustion by adjusting the operating parameters, and few effective boiler operating parameter predictions are given for very low-load conditions, i.e., below 20%. Various burner operation modes under ultra-low load conditions were analyzed using computational fluid dynamics (CFDs) methods; this operation was successfully tested with six types of pulverized coal combustion in this paper, and fitting models for outlet flue gas temperature and NOx emissions were derived based on the combustion characteristics of different types of pulverized coal. The results indicate that under 20% ultra-low-load conditions, the use of lower burners leads to a uniform temperature distribution within the furnace, achieving a minimum NOx emission of 112 ppm and a flue gas temperature of 743 K. Coal type 3, with the highest carbon content and a calorific value of 22,440 kJ/kg, has the highest average section temperature of 1435.76 K. In contrast, coal type 1 has a higher nitrogen content, with a maximum cross-sectional average NOx concentration of 865.90 ppm and an exit NOx emission concentration of 800 ppm. The overall lower NOx emissions of coal type 3 are primarily attributed to its reduced nitrogen content and increased oxygen content, which enhance pulverized coal combustion and suppress NOx formation. The fitting models accurately capture the influence of pulverized coal composition on outlet flue gas temperature and NOx emissions. This control strategy can be extended to the stable combustion of many kinds of coal. For validation, the fitting error bar for the predicted outlet flue gas temperature based on the elemental composition of coal type 6 was 8.09%, whereas the fitting error bar for the outlet NOx emissions was only 1.45%.

C:N stoichiometry and the fate of organic carbon in ecosystems of the northwest Pacific Ocean

Phytoplankton elemental composition regulates the efficiency of energy and material transfer in the interface between phytoplankton and their consumers. The ratio of particulate organic carbon to particulate organic nitrogen (POC:PON) shows considerable regional deviations from the canonical Redfield ratio in the global surface ocean. However, in certain oceanic regions such as the northwest Pacific Ocean (NWPO) POC:PON distribution and its ecological significance remain uncertain. We investigated surface ocean POC:PON distributions at 66 stations in the NWPO, and quantified the correlations between POC:PON and multiple biotic and abiotic factors including sea surface temperature (SST), nutrient concentrations and multiple lipid biomarkers (fatty acids and sterols), by combining correlation analyses and generalized additive models. POC:PON (range: 3.53–14.18 M ratios; median: 6.89) was overall higher in the (sub)tropical biome than that in the high-latitude biome. In the entire study region, SST, nutrient concentration and lipid-derived phytoplankton community structure explained 41 %, 33 % and 26 % of the variance in POC:PON, respectively, while the respective importance of each factor differed between the (sub)tropical and high-latitude biomes. Furthermore, we calculated the percentage of primary production consumed by herbivores (PPC; 54–156 %), showing a higher mean value (117 %) in the high-latitude biome and a lower one (92 %) in the (sub)tropical biome. The spatial distribution pattern of PPC can be attributed to multiple factors, with PPC correlating negatively with SST and positively with lipid-based indicators of phytoplankton food quality and POC concentrations. The increase in SST may be associated with a reduced nitrogen content, resulting in lower PPC in the (sub)tropical biome. This study highlights the significance of SST and elemental and biochemical composition of phytoplankton in regulating the transfer of organic carbon to herbivores in the NWPO.

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.

Impact of low-temperature and low-pressure mild oxidation after plasma solidification on electrical properties and reliability in ultra-thin SiON MOSFETs

The impact of different SiON manufacturing processes on performance and reliability behaviors has been investigated for the MOSFETs. The performance of devices composed of an ultrathin SiON film fabricated by the novel low-temperature and low-pressure mild oxidation after the plasma solidification (LLMOPS) method can be enhanced compared to conventional processes, which is attributed to the increased mobility. It is observed from secondary ion mass spectrometry analysis that the distribution of nitrogen with the LLMOPS process moves toward the upper surface of SiON. As a result, the p-MOSFET manufactured by the LLMOPS process exhibits lower electrical performance degradation during the NBTI stress, indicating that a reduction in nitrogen concentration at the Si/SiO2 interface contributes to improving NBTI behavior. It is also demonstrated that the inhibition of NBTI phenomena enhances the frequency stability on the ring oscillator with circuit simulation. Thus, the LLMOPS process is a promising approach to improve the performance and reliability of MOSFETs in mass production.

Unraveling catalytic conversion of spent coffee grounds through alkaline and alkaline earth metal phosphates in hydrothermal carbonization

Hydrothermal carbonization (HTC) offers a promising pathway for sustainable energy production, with spent coffee grounds (CG) emerging as an eco-friendly feedstock for hydrochar generation. However, the potential applications of alkaline and alkaline earth metal phosphates as catalysts for novel carbonaceous materials remain largely unexplored. This study investigates the impact of alkaline types on the characteristics, morphology, and heating value of hydrochar derived from CG. Incorporating Mg3(PO4)2, K3PO4, and Na3PO4 into HTC processes resulted in significant reductions in carbon content, leading to decreased hydrochar yield, higher heating value (HHV), and energy yield (EY). Notably, HHV reduction ranged from 2 % to 15 %, depending on catalyst type and temperature. The catalysts contributed to increasing ash content in hydrochar due to their inorganic nature. The presence of catalysts minimally impacted the hydrochar surface functional groups, with a more amorphous structure observed at 200 °C across all samples. A higher abundance of microspheres was observed in hydrochar catalyzed by K3PO4 and Na3PO4 at 200 °C compared to Mg3(PO4)2. Interestingly, K3PO4 and Na3PO4 reduced nitrogen content of the hydrochar rather than Mg3(PO4)2. The proposed catalytic mechanism involved metal phosphate catalyzing hydrolysis reactions, thereby reducing hydrochar yields while augmenting volatile fatty acid (VFA) and furan contents in the process water. Alkaline and alkaline earth metal phosphates catalysts exhibited trade-offs between hydrochar properties and hydrolysis byproducts in the HTC of CG.

Innovative Cultivation Practices for Reducing Nitrate Content in Baby Leaf Lettuce Grown in a Vertical Farm

The aim of this research is to introduce innovative cultivation practices that result in reduced nitrate levels in baby leaf lettuce grown under vertical farming conditions while maintaining high productivity. For this reason, three experiments were conducted. The first experiment focused on the impact of two “white” light spectra with a blue:green:red:far-red ratio of 14:32:43:10 (BlowRhigh) and 21:34:36:7 (BhighRlow). The second experiment assessed the effects of two nitrogen supply conditions: sufficient total nitrogen (N15) and limited total nitrogen (N5), and foliar biostimulant application. In the third experiment, the impact of replacing the nutrient solution in the N15 treatment with tap water for an additional 24 h (TW24) on leaf nitrate content was examined. Results from the lighting experiment revealed no significant effects on agronomical parameters or nitrate content between the two light spectra. Reducing nitrogen content in the nutrient solution reduced leaf nitrate content but negatively influenced agronomical characteristics. Biostimulant application and replacing the nutrient solution with water reduced leaf nitrate content compared to the control and positively affected growth. The most favorable outcomes were observed in plants supplied with sufficient nitrogen and foliar biostimulant but also cultivated for an additional 24 h with tap water (Sp-N15-TW24).

Synthesis of castor oil/PEG as textile softener

New castor oil/polyethylene glycol (CAO/PEG) hybrids were synthesized by reacting of CAO with PEG 300, 600, 1000, 2000 or 4000, in presence of ammonium per sulfate (APS) as an initiator. The optimum conditions to synthesis such hybrids are: PEG/CAO weight ratio, 35%; APS/PEG weight ratio, 15%; reaction temperature, 80 °C; and reaction time, 60 min. Only the hybrids based on PEG 1000 and 2000 formed oil in water stable emulsions. Treating cotton fabric samples with easy care finishing formulation containing 40 g/L of the synthesized hybrids emulsions results in an enhancement in softness, tensile strength, whiteness index, and stiffness along with a reduction in nitrogen content, wrinkle recovery angle, and wettability properties of treated fabric, compared to that sample finished in absence of that emulsions. The chemical structure of the synthesized CAO/PEG1000 hybrid was confirmed via the FTIR and 1HNMRanalysis whereas the TEM analysis showed that the particles size of that hybrid emulsion is in the range of 27–105 nm. Moreover, such hybrid emulsion treated fabric surface was characterized via SEM and EDX analysis. Furthermore, treating dyed samples with the nominated hybrid emulsion improves the color strength of that samples but keeps the washing fastness, wet rubbing fastness as well as alkaline perspiration fastness of the dyed/finished samples unchanged. The wet rubbing fastness and alkaline perspiration fastness of all the dyed/finished samples were enhanced while the light fastness of such samples decreased.

Role of income and policy in reducing water pollution: Evidence from the Mississippi River Basin Healthy Watersheds Initiative

AbstractWe study the effectiveness of the Mississippi River Basin Healthy Watersheds Initiative (MRBI) in reducing nitrogen pollution in surface water bodies. We use a Kitagawa‐Oaxaca‐Blinder (KOB) counterfactual decomposition method to quantify the role of income and policy in reducing nitrogen pollution in waterbodies. Our results show that the MRBI policy for the 2012 cohort of implemented watersheds across five states (Arkansas, Indiana, Iowa, Kentucky, and Tennessee) experienced a 43% reduction in nitrogen concentrations when comparing the 2009–2011 pre‐treatment period to the 2012–2018 post‐treatment period. Decomposition results show that 79% of the improvement in water quality from policy treatment is derived from an endowment effect, driven mainly by location‐fixed effects that include cross‐sectional mean differences in income, among other characteristics. Results also show that 21% of differences are derived from the coefficient effect or differences in the response of policy‐treated watersheds compared to a set of control watersheds.

Calcium-enriched biochar shifts negative effects of fluoride on the properties of arid sandy soil.

This study sheds light on the influence of fluoride on the changes in the properties of alkaline sandy soils and the efficiency of calcium-enriched biochar application. The investigation involved an incubation experiment with soil contaminated with varying NaF concentrations (0, 400, 800, and 1200 mg NaF kg-1 soil) and biochar (1% w/w). The data revealed that adding NaF to the soil resulted in significant increases in soil pH and decreases in total nitrogen (TN) content. Short-term fluoride pollution did not affect the microbial abundance due to certain factors such as increased soil pH and decreased microbial metabolism promoting the survival of cells under fluoride stress. However, a shift from bacterial to fungal-dominated microbial communities was observed at the highest NaF concentration. The nitrogen functional gene amoA was found to be highly sensitive to fluoride toxicity. The decrease in the abundance of amoA gene and the increase in soil pH can explain reduced nitrogen concentration. On the other hand, our findings indicated a significant decrease in enzyme activity in soil contaminated with mild to severe levels of NaF. This reduction in enzyme activity can be attributed to increased soil pH, decreased TN content, and the inhibition of microbial metabolism due to fluoride toxicity. Furthermore, the addition of calcium-rich biochar reduced fluoride solubility and adjusted pH, mitigating the negative effects of fluoride toxicity on soil properties. The use of biochar was also found to inhibit the accumulation of soil fluoride-resistant microbial genes.

Suaeda australis and its associated rhizosphere microbiota: a comparison of the nutrient removal potential between different shrimp farm sediments in New Caledonia.

Shrimp rearing generate organic waste that is trapped in the pond sediment. In excess, these wastes may impair aquaculture ecosystem and shrimps' health. To promote the biological oxidation of accumulated organic waste, the pond is drained and dried at the end of each production cycle. However, this practice is not always conducive to maintaining microbial decomposition activities in sediments. Shrimp production in New Caledonia is no exception to this problem of pollution of pond bottoms. One promising way of treating this waste would be bioremediation, using a native halophyte plant and its microbiota. Thus, this study explored the nutrient removal potential of Suaeda australis and its microbiota on sediments from four shrimp farms. Suaeda australis was grown in an experimental greenhouse for 6 months. In order to mimic the drying out of the sediments, pots containing only sediments were left to dry in the open air without halophytes. An analysis of the chemical composition and active microbiota was carried out initially and after 6 months in the sediments of the halophyte cultures and in the dry sediments for each farm, respectively. In the initial state, the chemical parameters and the microbial diversity of the sediment varied considerably from one farm to another. Growing Suaeda australis reduced the nitrogen, phosphorus and sulfur content in all type of sediment. However, this reduction varied significantly from one sediment to another. The rhizosphere of Suaeda australis is mainly composed of micro-organisms belonging to the Alphaproteobacteria class. However, the families recruited from this class vary depending on the farm in question. Depending on the sediment, the variation in microbiota leads to different putative biochemical functions. For two of the farms, a similar reduction in nitrogen concentration was observed in both dry and cultivated sediments. This suggests that certain initial chemical characteristics of the sediments influence the nutrient removal efficiency of Suaeda australis. Our study therefore highlights the need to control the pH of sediments before cultivation or in dry sediments in order to ensure optimal microbial decomposition of organic waste and nutrient cycling.

Growth, Physiology and Nutritional Quality of C4 Halophyte Portulaca oleracea L. Grown Aeroponically in Different Percentages of Artificial Seawater under Different Light-Emitting Diode Spectral Qualities.

Edible halophyte Portulaca oleracea L., known as purslane, was grown in two percentages of artificial seawater (ASW) under two combined red (R) and blue (B) LED spectra. High salinity (40% ASW) negatively affected shoot productivity and leaf growth of purslane compared to those grown in 10% ASW. Photosynthetic pigment and total reduced nitrogen concentrations were significantly higher in purslane grown in 10% ASW than in 40% ASW. However, LED spectral quality did not markedly influence these parameters. Grown in 10% ASW under R/B 2.2, purslane had the highest maximum nitrate reductase activity, while those in 40% ASW under R/B 2.2 had the highest activation state. Under both light qualities, purslane had a sevenfold increase in proline concentration in 40% ASW than in 10% ASW. Total phenolic compounds' concentration was the highest in 10% ASW under R/B 0.9, while there were no significant differences in the accumulation of total soluble sugars and ascorbic acids among all plants. Antioxidant enzymes activities were lower in 40% ASW under R/B 2.2 compared to the other conditions. In conclusion, salinity affected the yield, physiology and nutritional quality of purslane. The impacts of LED spectral quality on purslane were only reflected by certain physiological and nutritional parameters.

Reducing total nitrogen and dimethyl sulfide content of dry malt extract powder via spray-freeze drying method

Abstract Dry malt extract (DME) is powder prepared by dehydrating the wort, which is mainly produced by spray drying on the market. In addition, the beer industry has problems with the nitrogen content of wort, which is not easily controlled, and with the undesired volatile dimethyl sulfide (DMS), which is caused unpleasant odors in beer. In this study, DME was prepared using spray-freeze drying (SFD) technology by comparing with freeze dried DME and spray dried DME. The results show that SFD can be used as a novel engineering technique to improve the physical properties of DME having a narrow particle size distribution as well as high solubility and flowability. The freezing process was found to migrate proteins to the droplet surface by elemental analysis, and the drying process partially modified the surface protein and SFD powder fragility characteristics to achieve the purpose of reducing nitrogen content in DME.

Optimising mechanical separation of anaerobic digestate for total solids and nutrient removal

Mechanical separation of anaerobic digestate has been identified as a method to reduce pollution risk to waterways by partitioning phosphorus in the solid fraction and reducing its application to land. Separators have adjustable parameters which affect separation efficiency, and hence the degree of phosphorous partitioning, but information on how these parameters affect separation performance is limited in the literature. Two well known technologies were investigated, decanter centrifuge and screw press, to determine the most efficient method of separation. Counterweight load and the use of an oscillator were adjusted for the screw press, while bowl speed, auger differential speed, feed rate and polymer addition were modified for the decanter centrifuge. Separation efficiency was determined for total solids, phosphorus, nitrogen, potassium, and carbon, and the total solids content of resulting fractions was measured. The decanter centrifuge had higher separation efficiency for phosphorus in all cases, ranging from 51% to 71.5%, while the screw press had a phosphorus separation efficiency ranging from 8.5% to 10.9% for digestate of ∼5% solids (slurry/grass silage mix). Separation by decanter centrifuge partitioned up to 56% of nitrogen in the solid fraction leaving a reduced nitrogen content in the liquid fraction available for land spreading; this nitrogen would most likely need to be replaced by chemical fertiliser which would add to the cost of the system. The decanter centrifuge is better suited to cases where phosphorus recovery is the most important factor, while the screw press could be advantageous in cases where cost is a limiting factor.

The Yield and Quality Formation of Wheat Induced by Exogenous Strigolactones in Drought Condition

Drought is one of the major disasters affecting wheat. The change of wheat yield and quality directly affects the global population diet health. In this study, Strigolactones (SL) were sprayed on the leaf surface to study the relationship between wheat photosynthesis, nitrogen transport and yield and quality formation, further clarifying the influence of Sl on the synergic formation of yield and quality. The results showed that Sl could promote the accumulation of photosynthetic pigments in leaves, reduce nitrogen content in aging leaves and improve nitrogen transport level, then promote the improvement of grain yield and quality, so as to provide a reference for the application of Sl in wheat stress-resistant cultivation.

Nannochloris sp. Microalgae Strain for Treatment of Dairy Wastewaters.

This paper focuses on a process for dairy wastewater treatment by mixotrophic cultivation of microalgae Nannochloris sp., using cheese whey obtained as a side flow from cheese production as an organic carbon source. The microalgae samples were prepared by adding to the standard growth medium increasing amounts of cheese whey, calculated to ensure a lactose concentration between 0 and 10 g/L. The samples were incubated at a constant temperature of 28 °C and 175 rpm stirring speed for a total time of seven days. Two LED (Light Emitting Diode) illumination schemes were applied in order to assess the effect of this parameter on microalgae development and bioactive compound accumulation: continuous illumination (light stress) versus alternative cycles of 12 h light-12 h dark (day-night cycle). The growth medium was analyzed before and after microalgae cultivation in order to determine the reduction of carbon, nitrogen, and phosphorus. The results obtained for this process, after a seven-day cultivation period, were as follows: reduction of 99-100% of lactose from the growth medium, up to 96% reduction in chemical oxygen demand, up to 91% reduction in nitrogen content, and up to 70% reduction in phosphorus content.

The efficiency of boric acid as an alternate to NaCl for the preservation of cattle hides.

The fresh buffalo hides (n = 6) were cut into two equal parts and categorized into three equal groups. The first group was treated with 50% NaCl; the second group hides were treated with 5% of boric acid (BA), and the third group hides were with NaCl + BA (10:1). Hair loss was seen at the sample margins of hides treated with 50% NaCl, with a slight odor. In the second group, there was neither hair loss nor a pungent smell was felt. The nitrogen content of the preserved hide was measured at different durations during the experimental period, i.e., 0h, 24h on day 7th, and day 14th. The nitrogen level reduced significantly (P < 0.05) from 0h to day 14th of the experiment in hides treated with 50% of NaCl and 5% of boric acid, while this trend was found non-significant (P > 0.05) in hides treated with the combination of NaCl + BA. At 0h, the moisture content for 50% of NaCl-treated hides was 64.82 ± 0.38% moisture content for 5% of boric acid was 63.89 ± 0.59, while for the NaCl + BA combination 61.69 ± 1.09 was observed. Moisture content for 50% of NaCl on day 14th was 38.87 ± 0.42; for boric acid, it was 37.76 ± 1.12, and for the combination of both, the moisture content was 34.56 ± 0.41%. A similar decreasing trend of moisture contents was found in hides treated with different preservatives. After 14days of treatment, the bacterial count for 50% of NaCl was 2 × 109; for boric acid, it was 1 × 109, and for the combination of both, the bacterial count was 3 × 109. The lowest pollution load was observed hides treated with the combination of NaCl + BA (10:1). Total solids (TS) were 21.69 ± 0.57 while total dissolved solids (TDS) were 21.10 ± 0.57, and total suspended solids were 0.60 ± 0.57mg/l. It is concluded from the present study that boric acid alone or in combination with NaCl efficiently reduced nitrogen content and bacterial count and can reduce water pollution in tannery and hence could be used as a preservative for the hide in the tannery industry.

A hybrid optimization approach towards energy recovery from torrefied waste blends

The bottleneck of urban forest waste (UFW) as biofuel relies on surpassing its logistical management, feedstock quantity and supply, heterogeneity, and property drawbacks. This article proposes a hybrid approach based on multicriteria decision methods (MCDM) and response surface methodology (RSM) to optimize the definition of UFW blends and their torrefaction (temperature and process time). First, proximate, ultimate, and calorific analysis of UFWs (S1.Mangifera indica, S2.Ficus benjamina, S3.Pelthophorum dubium, S4.Persea americana, S5.Anadenanthera colubrina, and S6.Tapirira guianensis) were assessed. Then, understanding that UFW relies on species that do not always show promising characteristics as biofuels, the MCDM was applied to feedstock properties defining an optimum blend (OB) composed of 73%, 12.5%, and 14.5% of S1, S5, and S6, respectively. Next, the OB torrefaction was optimized using a central composite design (RSM-CCD), providing prediction models, the optimum torrefaction condition (273.3 °C and 40 min), and a torrefied optimum blend (TOB). Finally, the approach was validated by assessing TOB's properties, combustion behavior, and gaseous emissions. The methodology supplied a TOB with lower ash (2.67%), an HHV of 20.87 MJ kg−1, reduced nitrogen content (up to 39.65%), and more stable combustion resulting in a superior solid biofuel with a lower potential of NO-emissions in further applications.

Large root cortical cells and reduced cortical cell files improve growth under suboptimal nitrogen in silico.

Suboptimal nitrogen availability is a primary constraint to plant growth. We used OpenSimRoot, a functional-structural plant/soil model, to test the hypothesis that larger root cortical cell size (CCS), reduced cortical cell file number (CCFN), and their interactions with root cortical aerenchyma (RCA) and lateral root branching density (LRBD) are useful adaptations to suboptimal soil nitrogen availability in maize (Zea mays). Reduced CCFN increased shoot dry weight over 80%. Reduced respiration, reduced nitrogen content, and reduced root diameter accounted for 23%, 20%, and 33% of increased shoot biomass, respectively. Large CCS increased shoot biomass by 24% compared with small CCS. When simulated independently, reduced respiration and reduced nutrient content increased the shoot biomass by 14% and 3%, respectively. However, increased root diameter resulting from large CCS decreased shoot biomass by 4% due to an increase in root metabolic cost. Under moderate N stress, integrated phenotypes with reduced CCFN, large CCS, and high RCA improved shoot biomass in silt loam and loamy sand soils. In contrast, integrated phenotypes composed of reduced CCFN, large CCS, and reduced LRBD had the greatest growth in silt loam, while phenotypes with reduced CCFN, large CCS, and high LRBD were the best performers in loamy sands. Our results support the hypothesis that larger CCS, reduced CCFN, and their interactions with RCA and LRBD could increase nitrogen acquisition by reducing root respiration and root nutrient demand. Phene synergisms may exist between CCS, CCFN, and LRBD. CCS and CCFN merit consideration for breeding cereal crops with improved nitrogen acquisition, which is critical for global food security.

Speciation and transformation of nitrogen for sewage sludge hydrothermal carbonization-influence of temperature and carbonization time

Hydrothermal carbonization (HTC) is an effective means of energizing high-water-content biomass that can be used to convert sewage sludge (SS) into hydrochar and reduce nitrogen content. To further reduce the emission of NOx during the combustion of hydrochar and seek proper disposal method of liquid product, the mechanism of nitrogen conversion was studied in the range of 180–320 °C and 30–90 min. At 180–220 °C, 42.15–52.91% of the nitrogen in SS was transferred to liquid by hydrolysis of proteins and inorganic salts. At 240–280 °C, the nitrogen in hydrochar was mainly in the form of heterocyclic -N (quaternary-N, pyrrole-N, and pyridine-N). The concentration of NH4+-N increased from 6.82 mg/L (180 °C) to 26.58 mg/L (280 °C) due to the enhancement of the deamination reaction. At 300–320 °C, pyrrole-N (from 15.92% to 9.38%) and pyridine-N (from 5.52% to 3.73%) in the hydrochar were converted to the more stable quaternary-N (from 0.31% to 4.28%). Meanwhile, the NH4+-N and amino-N in the liquid decomposed into NH3. Prolonging the carbonization time promoted the hydrolysis of proteins, the conversion of heterocyclic -N, and the production of NH3. Under optimal reaction conditions (280 °C and 60 min), the nitrogen in the SS is converted to stable forms and the energy balance meets the requirements of circular-economy. The results show that temperature determines the nitrogen form and the carbonization time affects the nitrogen distribution. So HTC has the potential to reduce NOx emissions from SS energy utilization processes.