Nitrogen Content Research Articles

Scenarios for precision nitrogen management in potato: Impact on yield, tuber quality and post-harvest nitrate residues in the soil

Potato belongs to the category of the staple food playing an important role in global food security and nutrition. Because potato plants have a shallow root system and stop nitrogen uptake early in the growing season (between 20 and 60 days after emergence), potato fields are more prone to leaching of nitrate to lower soil layers and the groundwater than deep rooting crops, thus posing a higher risk for polluting the environment with nitrate. On the other hand, lowering fertilizer dosages could result in yield loss and reduced tuber quality. To balance the risk of yield and quality loss against the risk of nitrate leaching, the fertilization dose should be adapted to the local production potential, which can vary considerably within a field. However, there is no consensus on how to adapt the fertilization to this variability. Therefore, the objective of this study was to assess various N fertilization scenarios and their effect on the concentration of residual nitrate, total potato yield and tuber quality. Five potato fields located in Flanders with historical spatial variation in crop productivity were selected as potential candidates for implementing site-specific nitrogen management practice. The fields were divided into management zones based on variation visible in soil maps, maps of electrical conductivity, maps of vegetation indices and soil samples. Nitrogen was applied in three different dosages, including the conventional dose, and two reduced fertilization levels. Based on time series of vegetation indices, cumulative vegetation indices and pair-wise correlations between the vegetation index values obtained from Sentinel-2 satellite imagery (FAPAR, NDVI, FCOVER, LAI) only two fields of five showed temporal stability of the spatial management zones, while in three other fields the zone performance shifted depending on the weather conditions during the growing season. In the fields with stable zones, the lowest N fertilization levels in the areas with lower productivity potential resulted in a reduction of the concentration of leachable nitrates while total yield and potato tuber quality (dry matter and nitrogen content) did not change. For this type of fields with temporally stable zones, it was concluded to recommend reducing the nitrogen dosage in the zones with a lower productivity potential and high mineralization levels to limit nitrate leaching. In the fields where better performing zones change their location in wet and dry years, significant differences between treatments in the total potato yield, dry matter and nitrogen content in the tuber were also often detected. However, application of a low nitrogen dose during the first fertilization in one of the zones in such fields is not recommended as it is not yet known how the zones will behave the coming season, leading to a risk for underfertilization of these zones. Therefore, conventional fertilization remains the recommended practice in case the production potential of the zones depends on the weather during the growing season and is not yet known at the moment of fertilization. However, fertilizer fractions applied later during the growing season may be adapted to the crop development and actual weather conditions.

Enhancing crop yield and microbial diversity in saline-affected paddy soil through biochar amendment under aquaculture wastewater irrigation

Biochar is frequently employed to ameliorate saline-affected paddy soil. However, there are controversial research findings regarding the applicability of biochar for the enhancement of soil physicochemical properties and agricultural (crop) yield, particularly under conditions of wastewater irrigation in agricultural production. This study investigates the effects of controlled soil salinity levels (1 ‰ and 3 ‰), induced using sodium chloride, and the targeted application of biochar in a pot experiment. The study examines the impact on physicochemical characteristics of different soil layers, physicochemical properties, and physiological responses of rice plants irrigated with aquaculture wastewater. It also delves into soil microbial diversity and the predominant bacterial species. The research findings reveal that biochar exerts a significant influence on soil properties and nitrogen content in saline environments. The addition of biochar enhanced soil electrical conductivity (EC), modulated the distribution of organic carbon, and altered nitrogen transformation processes within the soil. Consequently, biochar application resulted in a 14.2 % and 6.81 % increase in rice yield at 1 ‰ and 3 ‰ salinity levels, respectively. Furthermore, biochar increased leaf area by 25.3 % and 45.9 % in 1 ‰ and 3 ‰ salinity stress separately and enhanced the nitrogen content (TN) in leaves by 28.6 % when the soil salinity is 1 g/kg, demonstrating a positive impact on nitrogen uptake. Additionally, biochar has shown potential in mitigating nitrous oxide (N2O) emissions. Its addition led to a reduction in the relative abundance of Actinobacteria while increasing the relative abundance of Firmicutes. These findings provide novel insights into the transformative potential of biochar in improving the characteristics of saline paddy soil and augmenting rice yield when used in conjunction with aquaculture wastewater irrigation.

Restoration of degraded seagrass meadows: Effects of plant growth-promoting rhizobacteria (PGPR) inoculation on Zostera marina growth, rhizosphere microbiome and ecosystem functionality

The utilization of plant growth-promoting rhizobacteria (PGPR) holds great promise for the restoration of damaged terrestrial plant ecosystems. However, there is a significant knowledge gap regarding the application of PGPR in rehabilitating aquatic ecosystems. In this study, we conducted a mesocosm experiment to investigate the effects of Raoultella ornithinolytica F65, Pantoea cypripedii G84, Klebsiella variicola G85, Novosphingobium profundi G86, and Klebsiella pneumoniae I109 on eelgrass (Zostera marina L.), which is a crucial marine angiosperm. The application of these strains resulted in a significant increase in the new leaf area of eelgrass, with improvements of 55.4%, 14.4%, 39.1%, 20.6%, and 55.7% observed, respectively. Moreover, PGPR inoculation enhanced shoot biomass, rhizome elongation, leaf carbon and nitrogen content, as well as photosynthetic pigments. Furthermore, it stimulated enzymatic activities within the rhizosphere soil and positively influenced its physicochemical properties. The Illumina Miseq sequencing results revealed a positive shift in the bacterial community, leading to an enrichment of functional groups associated with nitrogen fixation and degradation of aromatic compounds. These findings underscore the significant potential of PGPR as a transformative tool for enhancing seagrass growth and survival, offering innovative strategies for the restoration of degraded seagrass meadows. This research not only advances our understanding of microbial-plant interactions in aquatic ecosystems but contributes to the broader goals of ecosystem revitalization and biodiversity conservation.

Spatial-spectral feature mining in hyperspectral corn leaf venation structure and its application in nitrogen content estimation

The growth of corn plants requires a significant amount of nitrogen nutrient supply to ensure the yield. Meanwhile, overfertilization could result in adverse environmental impacts, making it crucial to monitor the nitrogen supply condition in corn plants precisely. Hyperspectral imaging (HSI) could be the solution to this challenge, as HSI plant phenotyping technology has been widely utilized to nondestructively identify plant traits, such as mineral nutrient deficiencies in corn plants. However, limitations persist where the conventional HSI nitrogen prediction models mainly relied on the overall colors of the plant tissue extracted from the spectral domain but rarely included the spatially distributed information on the leaf level. This study aimed to examine if including new information from the spatial domain could potentially improve the performance of HSI models. Because the venation structure plays a crucial role in the distribution of various nutrients across the leaf, a series of physiological responses caused by nitrogen deficiency could result in non-uniform color patterns related to the veins. The recent advancement of HSI techniques such as LeafSpec, whose imaging quality and spatial-spectral resolution have been significantly improved, made it possible to extract the venation structure together with high-resolution spatial-spectral features. In this study, the hypothesis was that utilizing high-resolution spatial-spectral features extracted based on the venation structure could yield a better-performed nitrogen content prediction model compared to the averaged spectrum of the corn leaf. First, a venation structure segmentation algorithm was developed using the Local Binary Patterns (LBP) method for hyperspectral corn leaf images scanned with LeafSpec. Second, for every hyperspectral leaf image, 131 spectral index heatmaps were generated, and 30 leaf regions were picked based on the venation structure, resulting in 3930 spatial-spectral features. Third, the features were picked using the Least Absolute Shrinkage and Selection Operator (LASSO) regression. As the results tested with a field assay involving two different corn genotypes and two nitrogen treatments, the Partial Least Square Regression (PLS-R) model built with selected spatial-spectral features outperformed the model built with the averaged leaf spectra in terms of the Root Mean Squared Error (RMSE) of predictions. The results provided encouraging proof and guidance for the potential benefit of using high-resolution spatial-spectral features derived from hyperspectral leaf images to improve the accuracy and robustness of the nitrogen content prediction models for corn plants.

Isolation and identification of thermophilic cyanobacterium inhabiting Shiv Kund (Sohna hot spring), India through polyphasic approach: Bioprospecting in varying nitrogen environment for biotechnological interest particularly for biofuel potential

Identifying a potential candidate having optimal growth characteristics and high-value biotechnological attributes, especially biofuel profile in the era of high rising renewable energy demands is necessary for a sustainable algal-biorefinery perspective. Thermophilic cyanobacteria are scarcely investigated for their industrial potential. In this regard, a preliminary study was performed to isolate a thermophilic cyanobacterium from Shiv Kund, Sohna hot spring, Gurugram, India. The polyphasic approach with molecular identification through 16SrRNA and phylogenetic analysis identified the isolated thermophilic cyanobacterium as Fischerella thermalis PCC 7521 based on the 99.15 % similarity in the NCBI-BLASTn results. Further, the phenotypic visualization under light microscopy and Scanning Electron Microscope (SEM) confirms the true-branching filamentous nitrogen fixing cyanobacterium. To examine its potential for a biotechnological perspective, the effect of different nitrogen concentrations in the growth medium on the biochemical profiling was studied. The highest biomass production and biomass productivity per day obtained was 1041.6 mg/L and 42.33 ± 1.52 ⁎⁎(p < 0.01) in 0.1875 g/L (N/8) and 1.5 g/L (N) sodium nitrate concentration respectively. The effect of the growth phase on the biochemical profiling was also prominent and this helps in the cost-effective production of the required product. Surprisingly, nitrogen starvation has resulted in the increased production of pigments (chlorophyll, phycocyanin and carotenoids), proteins and lipids. The maximum carbohydrate production observed was under complete nitrogen availability (N) in the growth medium with 37.4 % more production in N than complete nitrogen starvation (N0) on 15th day of the growth cycle. Interestingly, the total lipid production observed was 457.41 ± 18.3 μg/mg ⁎(p ≤ 0.05) in N0 condition and 519.28 ± 21.3 μg/mg ⁎⁎(p < 0.01) in N/8 condition on 15th and 20th day of the growth cycle respectively. The effect of nitrogen concentrations on the C/N ratio and different functional groups were also examined. Overall, the results indicated F. thermalis PCC 7521 is a promising candidate for different biotechnological fields, especially biofuel production.

Promoting role of nitrogen-fixing bacteria and biochar on nitrogen retention and degradation of PBAT plastics during composting.

Since the increasing number of polybutylene adipate terephthalate (PBAT)-based plastics entering the environment, the search for sustainable treatment methods has become a primary focus of contemporary research. Composting offers a novel approach for managing biodegradable plastics. However, a significant challenge in the composting process is how to control nitrogen loss and enhance plastic degradation. In this context, the effect of various additives on nitrogen retention, PBAT plastics degradation, and microbial community dynamics during composting was investigated. The findings revealed that the addition of nitrogen-fixing bacteria Azotobacter vinelandii and biochar (AzBC) significantly improved nitrogen retention and accelerated PBAT rupture within 40 days of composting. Specifically, the PBAT degradation rate in the AzBC group reached 29.6%, which increased by 12.14% (P<0.05) compared to the control group. In addition, the total nitrogen (TN) content increased by 6.20% (P<0.05), and the Nitrogen-fixing enzyme (NIT) content increased by 190 IU/L (P<0.05). Further analysis of GC-MS confirmed the presence of low molecular weight fragmentation products, such as 6-(4-hydroxybutoxy)-6-oxohexanoic acid. The AzBC treatment promoted the proliferation of Klebsiella at the genus level that could enhance nitrogen retention and the bacteria that have the ability to degrade PBAT, such as Proteobacteria and Firmicutes at the phyla level, and Pseudoxanthomonas, Pseudomonas, and Flavobacterium genera at the genera level (P<0.05). Correlation analysis indicated that the degradation of PBAT is positively correlated with Temperature (T), NIT, and TN, but negatively correlated with the organic matter (OM) content and germination index (GI). In conclusion, the co-application of biochar and Azotobacter vinelandii offers promising sustainable prospects for enhancing PBAT plastic degradation and reducing nitrogen loss during composting.

Vermicomposting organic waste with Eisenia fetida using a continuous flow-through reactor: Investigating five distinct waste mixtures

In this study, the vermicomposting of source-separated organic solid waste was investigated using Eisenia fetida in a continuous flow-through reactor. This novel approach is capable of simulating the complex interactions and dynamics of a full-scale vermicomposting system, offering valuable insights into the optimization of organic waste management. The primary objective of the research was to evaluate the quality of vermicompost produced in the reactor and determine its compliance with regulatory standards. For this purpose, food waste, yard waste, and pruning waste were mixed in different proportions to create five waste mixtures, which were then subjected to an 8-week pre-composting process. Subsequently, vermicompost was produced from the pre-composted waste mixtures using a continuous flow-through reactor that allows for long-term operation without disturbing the worms. While the total Kjeldahl nitrogen (TKN) content of the vermicomposts ranged from 2.04% to 2.48%, the total organic carbon (TOC) content of the vermicomposts was between 25.68% and 32.64%. Therefore, the carbon/nitrogen (C/N) ratio was calculated to be between 12.60 and 13.66. The quality of the final compost product showed that it met the limitations suggested in the European Fertilizer Regulation for the main physico-chemical parameters and heavy metals. It is concluded that vermicomposting in a continuous flow-through system reactor would be applicable to different organic waste streams.

Preparation and optimization of sulfur ferrous inorganic carbon composite filler for autotrophic denitrification nitrogen and phosphorus removal

Sulfur autotrophic denitrification (SAD) occurs without organic carbon sources, offering advantages in removing nitrogen pollutants from water with low carbon to nitrogen ratio. However, ensuring nitrate–reducing sulfide–oxidizing bacteria ability to access the necessary sulfur and inorganic carbon sources is a challenge. Therefore, this study investigated the feasibility of utilizing a SAD composite filler to mitigate nitrogen and phosphorus pollutants concentrations in secondary effluent of wastewater treatment plants (WWTPs) and reduce eutrophication risk in the receiving water. The use of paraffin optimized composite filler with a satisfying 3.70 % break rate and wear rate without dramatically deteriorating contaminant removal performance. The process achieved 94.26 % total nitrogen (TN) and 90.91 % PO43--P removal rates in treating synthetic wastewater; and 2.72±1.92 and 0.29±0.06 mg/L of TN and PO43--P discharge in treating WWTPs secondary effluent, respectively. The results indicated that denitrification performance of the filler was primarily influenced by variations in NH4+-N resulting from SAD and dissimilatory nitrate reduction to ammonia caused by differences in filler composition and preparation factors. Based on the performance difference in SAD, Fex+ leached by H+ in the filler changed, affecting phosphorus removal performance. The change in mechanical properties of the filler was primarily dependent on the surface characteristics of the filler and the content/type of the binder. This study demonstrates the feasibility of using SAD for advanced nitrogen and phosphorus removal from wastewater and applying sulfur/siderite integrated composite filler as a pilot, thereby offering insights for the preparation of SAD fillers.

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.

Waste wood tar based porous carbon electrodes for supercapacitors with excellent performances through condensation cross-linking modification

Wood tar is an unavoidable by-product during a slow-pyrolysis process of biomass, which is usually discarded as a waste and results in environment pollution. Recently, wood tar has been used as a starting material for carbon electrodes because of its thermoplasticity and high carbon content. However, wood tar is mainly composed of various light phenolic molecules, which usually leads to a low carbonization yield after carbonization and an inferior electrochemical performance after activation. In this work, in order to improve the carbonization rate and electrochemical performance of these materials, wood tar was first condensed and crosslinked with formaldehyde and urea via a condensation reaction to produce condensed macromolecular resins, which were then carbonized at 550°C and activated with KOH at 800°C to prepare high-performance nitrogen-doped carbon electrodes for supercapacitors. The samples possess high carbonization yield, large specific surface area (3515.1 m2g-1) and moderate nitrogen content (1.11%). The high-performance carbon electrodes fabricated by this method achieves a high capacitance of 437.8Fg-1 (6M KOH electrolyte) at 1A/g-1. The assembled supercapacitor has an energy density of 13.41Whkg-1 at a power density of 124.93Wkg-1. And the capacitance retention was essentially 100% after 10000 cycles at 5Ag-1. The study presents an innovative strategy for the production of porous carbon for supercapacitors using wood tar and improves carbonization yield via condensation cross-linking modification.

Strawberry Grown in an Indoor Vertical Farm Responds to Increased Photosynthetic Photon Flux Density When Calcium Is Supplied at Higher Concentrations

Indoor vertical farms can optimize light, temperature, humidity, and nutrient use, thus potentially maximizing crop growth and yield. However, the reported potential for enhanced crop growth and yield within these systems needs to be tempered against the understanding of the effects of this “forced growth”/optimal growth environment on “actual” plant performance to fully reap the benefits of these innovative vertical farming systems. We investigated the effect of calcium (Ca) on the production of strawberries in an indoor vertical farm system with varying photosynthetic photon flux density (PPFD). Fruit yield of plants fed with high Ca (9 meq·L−1) increased by 42.3% when the PPFD was 422 µmol·m−2·s−1; however, a subsequent increase to 572 µmol·m−2·s−1 resulted in a decline in fruit production. Plants treated with low Ca (5 meq·L−1) had a reduced yield and demonstrated no response to the PPFD. The observed increase in yield was associated with increased fruit production and total soluble solids. Plants exhibited 21.5% and 57.8% increases in the total dry weight when exposed to 422 and 572 µmol·m−2·s−1, respectively; however, Ca did not have any impact on this response. Independent of the Ca concentration, the photosynthesis rate increased by 16.1% and 22.2% when the PPFD increased to 422 and 572 µmol·m−2·s−1, respectively; however, the highest photosynthesis rate was recorded with 422 µmol·m−2·s−1 when the Ca level was 9 meq·L−1. High Ca-fed plants exhibited a reduction in Ca (−17.1%) content in their fruits when exposed to 572 µmol·m−2·s−1, which was likely caused by a dilution effect attributable to increased fruit biomass. In contrast, shoot Ca increased when plants were given high Ca when the PPFDs were 422 and 572 µmol·m−2·s−1. The Ca concentration in shoots correlated with the increasing yield, and a higher Ca concentration was associated with the increasing transpiration rate and stomatic conductance. Shoot phosphorus declined when plants were exposed to increased PPFD, and phosphorus was lower when plants were provided with 9 meq·L−1 of Ca; however, plants watered with low Ca solutions had more potassium. The shoot nitrogen content and micronutrient contents were unchanged regardless of the variations in PPFD or Ca. In summary, the favorable conditions for the cultivation of strawberry under controlled environments resulted in greater growth and fruit yield as long as Ca was provided at higher concentrations in the irrigation solutions (from 5 to 9 meq·L−1). We suggest that the higher demand of Ca that is necessary to satisfy the enhanced plant development observed in indoor farming systems may be connected to the role of Ca in the formation of new tissues, cell walls, and cell membranes.

Supplementation of lysophospholipids in calf starter: effects on growth performance, blood metabolites, health, and ruminal ammonia nitrogen concentration

The aim of the current study was to evaluate the effects of a commercial mixture of Lysophospholipids (LPL) in calf starter on performance, blood metabolites, antioxidant capacity, liver enzymes concentration, and health status of pre-weaning dairy calves. Forty-eight newborn female Holstein calves (37.5 ± 2.9kg of body weight) were randomly assigned to four treatments (12 replicates), which included the control (CON, without additive) and a commercial blend of LPL at 0.5, 1, and 1.5g/kg of starter feed. The body weight of the calves was measured using a digital scale on days 15, 30, 45, and d 63 of the experimental period to calculate the average daily gain (ADG). The individual starter intake and fecal score were measured daily. Blood samples were collected at 30 and 63 days, while fecal samples were collected for four consecutive days after weaning to measure nutrient digestibility. The treatments did not significantly afffect the total dry matter and starter intake. However, the supplementation of LPL resulted in an increase in the ADG and improved feed efficiency (FE, from1-63 d) compared to the CON group. The addition of LPL did not have any significant impact on the apparent digestibility of dry matter (DM), and organic matter (OM). Eether extract (EE) digestibility tended to increase with the addition of LPL. Calves that received starter feed containing 0.5g/kg of LPL had higher superoxide dismutase activity at 30 d of age compared to the intake.CON group. Additionally, the average fecal score significantly decreased in calves fed 0.5 and 1.5g/kg LPL compared with the CON group. These findings suggest that the inclusion of LPL at an average dose of 1g/kg of calf starter can improve the performance of pre-weaning Holstein dairy calves.

Alkaline hydrothermal cracking effect and substance transformation characteristics of caprolactam-containing sludge

Caprolactam is a crucial chemical intermediate, but its wastewater treatment process generates a significant amount of caprolactam-containing sludge. This study represented the first exploration of the effects of alkaline hydrothermal technology on the cracking and transformation of substances in this sludge. The cracking effect of caprolactam-containing sludge during hydrothermal treatment increased with rising reaction temperature and longer reaction time. With NaOH dosage in hydrothermal treatment increasing from 0 to 2 wt%, the volatile suspended solids (VSS) removal rate of the sludge increased from 44.5% to 74.8%, soluble chemical oxygen demand (SCOD) in the cracking liquid increased from 12772 mg/L to 22976 mg/L, and ammonia nitrogen concentration increased from 398.0 mg/L to 851.2 mg/L. However, the addition of Ca(OH)2 did not significantly affect the changes of sludge suspended solids, VSS and SCOD concentration, but increased the leaching of ammonia nitrogen (up to 745.0 mg/L). This was due to the secondary flocculation of Ca2+, which rebound with dissolved non-proteinaceous organic matter. Increasing temperature, reaction time, and alkaline dosage all enhanced the fluorescence intensity of dissolved organic matter (DOM). Moreover, higher reaction temperature and alkaline dosage reduced the proportion of proteinaceous products in DOM while increasing the proportions of fulvic acids, soluble microbial metabolites, and humic acid-like substances. The study provided crucial theoretical support for engineering application of this technology.

A diet containing mango peel silage impacts upon feed intake, energy supply and growth performances of male dairy calves

The major challenges for disposal of waste from fruit processing factories are high transportation costs, limited landfill availability and environmental pollution. Therefore, developing efficient waste management techniques to reduce transportation costs and environment pollution is important. In 2021, global mango production was estimated to be at 57 million tons and mango peel (MP) represents 7–24% of the whole fruit weight. MP has been considered for use as ruminant feed in the form of fresh, dried, or silage. Fresh MP was abundant during the mango season and high in fermentable carbohydrate, which can easily breakdown and pollute the environment if a proper waste management method is not implemented. Thus, in this study, fresh MP was ensiled after sun-drying for one day and then fed to male dairy calves as a roughage source to evaluate its effect on feed intake, digestibility, energy balance, BW gain, feed efficiency and blood metabolites. Eight growing crossbred weaned male dairy calves (Holstein Friesians × Zebu) were allocated into two groups [Control (n = 4) and mango peel silage (MPS, n = 4)]. This experiment lasted for 12 weeks and calves were housed in 3.0 × 1.5 meters individual pen with concrete floor. Before feeding times, the weights of feed ingredients were weighed and mixed for 15 min. Calves were then given their respective diets ad libitum twice a day, at 0800 and 1600 h. Daily feed offered and refusals were recorded to determine the daily feed intake. A digestion trial was performed over the last five days of the experiment. BW and measurements were recorded every two weeks to determine the weight gain and body physical changes. Blood was collected at the end of experiment to analyze serum biochemical parameters. Ensiling improved the energy and protein content and decreased fiber content of MP, thereby improving the forage quality. Feeding a diet containing MPS at 30% of DM weight, compared to an isonitrogenous Control diet increased (P < 0.05) feed intake, energy supply and energy balance, changes in body measurements, weight gain, feed efficiency, and glucose concentration, as well as lowered (P < 0.05) the blood urea nitrogen concentration of male dairy calves. Ensiling fresh MP after sun-drying for one day led to stable, high-DM silage. Therefore, ensiling fresh MP could improve the feed supply for ruminant production and be an effective waste management strategy for fruit processing businesses.

Genotypic variation in nitrogen fixation characteristics in faba bean (Vicia faba L.) under contrasting phosphorus fertilizer regimes

AbstractAssessment of the genetic variability is an important step in improving nitrogen (N2) fixation potential of faba bean (Vicia faba L.) genotypes. The study was conducted to evaluate the genotypic variation for symbiotic N2 fixation traits of faba bean under contrasting phosphorus (P) fertilizer regimes. Twenty and 12 genotypes in the field and greenhouse, respectively, were planted under two P fertilizer regimes (P− and P+ corresponding to 0 and 46 kg/ha) using a randomized complete block design with three replications. Analysis of variance indicated highly significant (p &lt; 0.01) variation among genotypes for all N2 fixation traits under both P regimes, indicating the availability of genotypic variation. Genotypes Obse, Dosha, Didea, Gebelcho, Gora, Moti, and Hachalu had better performance for N2 fixation traits and higher grain yield (GY) across all study conditions. Performances of all N2 fixation traits, except nitrogen harvest index, were better under P+ than under P−. P fertilizer application in the field resulted in 12.3, 12.9%, 18.9%, and 24.2% increase in the number of nodules per plant, nodule dry weight per plant (NDWP), N2 yield (NY), and the amount of N2 fixed (NF), respectively. In the greenhouse, 18.9%, 22.5%, and 27.2% increment was obtained for NDWP, NY, and NF, respectively, due to fertilizer application. Biplot analysis revealed that NF, NY, percentage of nitrogen derived from atmosphere (%Ndfa), shoot nitrogen concentration (ShN), and GY were the traits responsible for large genetic variation for N2 fixation. NF had higher heritability and formed a significant positive correlation with most nitrogen fixation traits, suggesting the potential of the trait to be improved through breeding.

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%.

The linear relationship between true protein and nitrogen contents of feed and food ingredients: calculating true protein from a new conversion factor

The linear relationship between true protein and nitrogen contents of feed and food ingredients: calculating true protein from a new conversion factor

Economic Analysis, Yield Optimization, and Competition Dynamics of Groundnut/Cereal Fodder Intercropping Systems in Pakistan's Semi Arid Tropics

This research focuses on the intercropping management options including aspects of yield performance, nitrogen contribution to groundnut and economical considerations through the usage of intercrop Maize, Sorghum and Pearl Millet under varying cuttings treatments. Intercropping is effective in increasing land productivity and efficiency in nutrient use and provides economic returns yet the best combinations have not been well explored. Randomised complete block design was used to assess the growth characteristics of plant height, modulation and nitrogen in sole cropping and intercropping treatments in which they make cuts. For sole crop, both, maize and pearl millet produced the highest green fodder yields of 13.40 t ha⁻¹ and 19.10 t ha⁻¹, respectively, and intercropping reduced the productivity for both crops but it was statistically significant, yield recorded in Maize (one cut) groundnut = 3.10 t ha⁻¹. Both nodulation and nitrogen content were maximum in sole groundnut, but they were lower when groundnut was grown in association with other crops. Among all competitive indices, the LER was the highest on maize (LER=1.72), pearl millet and sorghum indicated that intercropping enhances land use efficiency. This was facilitated by the Monetary Advantage Index (MAI) that provided much support to maize-groundnut intercrop, which was easily identified as the most appropriate option for inter-crop revenue generation with an MAI of Rs. 17,800. These results provide evidence for the suitability of maize as the best intercrop for the enhancement of productivity and profitability in groundnut based intercropping systems. This study adds valuable input to sustainable agriculture, particularly in that it expresses the yields and profits from distinct intercrop associations as numeral digits deemed useful by both the scientific and agricultural communities.

Effects of Rice Root Development and Rhizosphere Soil on Methane Emission in Paddy Fields

Paddy fields are important anthropogenic emission sources of methane (CH4). However, it is not clear how rice root development and rhizosphere soil properties affect CH4 emissions. Therefore, we selected rice varieties with similar growth periods but different root traits in the local area. We measured CH4 emission fluxes, cumulative CH4 emissions, root dry weight, root length, and the dissolved organic carbon (DOC), microbial biomass carbon (MBC), redox potential (Eh), ammonium nitrogen (NH4+–N), and nitrate nitrogen (NO3−–N) contents in rhizosphere soil. Methanogens and methanotrophs are crucial factors influencing CH4 emissions; thus, their abundance and community composition were also assessed. The result showed that CH4 fluxes of each rice variety reached the peak at tillering stage and jointing-booting stage. The CH4 emissions in tillering stage were the largest in each growth period. CH4 emissions had negative correlations with root length, root dry weight, Eh NO3−–N, methanotroph abundance, and the pmoA/mcrA ratio, and positive correlations with NH4+–N, MBC, DOC, and methanogen abundance. Path analysis confirmed methanogens and methanotrophs as direct influences on CH4 emissions. Root development and rhizosphere soil properties affect CH4 emissions indirectly through these microbes. This study suggests that choosing rice varieties with good root systems and managing the rhizosphere soil can effectively reduce CH4 emissions.

Response of soil biochemical properties and ecosystem function to microplastics pollution.

Microplastics (MPs)-induced changes in soil nutrient cycling and microbial activity may pose a potential risk to soil ecosystem. Although some studies have explored these topics, there is still a large space for exploration and a relative lack of research on the mechanism by which soil health and its functions are affected by these changes. Thus, this study investigated the effects of polyethylene (PE) MPs with two particle sizes (13μm and 130μm) at five concentrations (0%, 1%, 3%, 6% and 10%, w/w) on soil biochemical properties and ecosystem function. The findings revealed that the exposure to 13μm MPs significantly reduced soil respiration (Res) rate, β-glucosidase (Glu) and catalase (CAT) activity, which accompanied with enhanced urease activity and decreased soil pH, available phosphorus (AP), dissolved reactive phosphorus (DRP), dissolved organic carbon (DOC) and available potassium (AK) content in most cases. However, 130μm MPs exerted negligible influence on the DOC and DRP content, Glu and CAT activity. High concentrations of 130μm MPs significantly reduced soil pH, total dissolved nitrogen (TDN), AP and AK content, but significantly increased soil Res rate. Overall, soil ecosystem function was significantly reduced by the addition of MPs. The Res rate, soil AP and DRP content and Glu activity were the most important predictors of soil ecosystem function. We found that the risk posed by MPs to soil ecosystem function was dose-dependent and size-dependent. These findings underscore that MPs can alter soil functions related to soil nutrient cycling and provide further insights into MPs behavior in agroecosystems.