Baby maize (Zea mays L.) is a high-value horticultural crop widely cultivated due to its short growth cycle and strong market demand. However, intensive production systems often rely heavily on chemical fertilizers, leading to reduced nutrient use efficiency and potential soil degradation. The present study investigated the potential of the Priestia megaterium Thr45 to enhance soil fertility, improve crop performance, and optimize fertilizer management in baby maize cultivation. A field experiment was conducted using a three-factor factorial design consisting of bacterial inoculation, different urea application rates, and different KCl rates. Soil chemical properties, plant growth parameters, yield components, and nutrient composition of edible cobs were evaluated. The results showed that inoculation with P. megaterium Thr45 significantly increased available phosphorus and exchangeable potassium in soil compared with the non-inoculated control. Inoculated plants exhibited higher chlorophyll content, greater leaf development, and increased plant height during early growth stages. Bacterial inoculation also significantly improved yield components, including ear number, ear yield, edible cob yield, and plant biomass. Furthermore, the nutritional quality of baby corn was enhanced, as reflected by increased protein and mineral (N, P, and K) concentrations in edible cobs. Significant interactions between bacterial inoculation and fertilizer treatments indicated that the beneficial effects of P. megaterium Thr45 were closely associated with nutrient management practices. Notably, comparable yield and nutritional quality were achieved under reduced nitrogen and potassium fertilizer inputs when combined with bacterial inoculation. These findings highlight the novel potential of P. megaterium Thr45 as an effective biofertilizer for improving nutrient availability, maintaining high productivity, and supporting sustainable baby maize production with reduced chemical fertilizer inputs

Optimizing nitrogen fertilization and planting date is essential for improving forage maize productivity under semi-arid conditions. This study evaluated the effects of nitrogen application rates and planting dates on growth, forage yield, and quality of maize (Zea mays L.) in Upper Egypt. A two-year field experiment (2024–2025) was conducted at the Experimental Farm of Assiut University using a strip-plot design arranged in a randomized complete block design with three replications. Four planting dates (15 April, 15 May, 15 June, and 15 July) were assigned horizontally, while three nitrogen rates (167, 238, and 309 kg N ha−1) were applied vertically. Growth traits, fresh and dry forage yield, dry matter percentage, crude protein content, and protein yield were recorded at 60 days after sowing. Results showed that planting date, nitrogen rate, and their interaction significantly affected most measured traits in both seasons. Sowing in mid-May consistently produced the highest plant height, chlorophyll content, fresh and dry forage yield, and protein yield. Increasing nitrogen application enhanced biomass production and forage quality, with the highest values generally recorded at 309 kg N ha−1. The strongest yield response to nitrogen occurred when maize was sown at the optimal planting date, indicating that nitrogen utilization was closely linked to favorable environmental conditions. Phenotypic correlation and multivariate analyses revealed strong associations among vegetative growth traits and forage yield, with a single dominant factor explaining more than 91% of the variation in yield-related traits across seasons. Overall, the results demonstrate that synchronizing planting date with appropriate nitrogen fertilization is critical for maximizing maize forage yield and quality under semi-arid conditions. Mid-May sowing combined with adequate nitrogen supply represents an effective management strategy for forage maize production in Upper Egypt, while further research is needed to optimize nitrogen-use efficiency and long-term sustainability.

Estimating nitrogen (N) and the corresponding crude protein (CP) content in forage crops is essential for optimizing fertilization and livestock nutrition. However, standard methods such as the Dumas and Kjeldahl techniques are destructive, costly, and impractical for field use in certain regions of developing countries. This study evaluated four non-destructive approaches—morphometric measurements, Pantone® color scales, smartphone-based RGB analysis (ColorDetector app), and SPAD chlorophyll readings—for predicting N and CP in Megathyrsus maximus (Mombasa grass). A total of 120 samples were collected under three nitrogen fertilization levels and assessed using linear mixed-effects models with cross-validation. Morphometric variables showed poor performance (R2 < 0.01), indicating low correlation with nutrient content. Pantone-based RGB models provided slightly better predictions (R2 ≈ 0.30) but were limited by subjectivity and discrete data. SPAD-based models demonstrated moderate predictive accuracy (R2 ≈ 0.53; RMSE ≈ 0.46%). The highest accuracy was achieved with smartphone-derived RGB data, where full RGB models reached R2 = 0.60 and RMSE = 0.45%. Based on these results, a practical green color scale was developed from RGB values to support real-time, in-field nitrogen and crude protein assessment. This study highlights smartphone imaging as a scalable, low-cost, and accurate tool for non-destructive estimation of nitrogen and crude protein in tropical forages, offering an accessible alternative to laboratory methods for producers and field technicians.

The increasing demand for sustainable agriculture requires innovative strategies to enhance nitrogen use efficiency while minimizing environmental losses associated with conventional fertilizers. This study aimed to develop and compare ammonium chloride- and ammonium nitrate-modified nanobiochar as controlled-release nitrogen carriers and to elucidate their effects on nitrogen retention, soil properties, and physiological nitrogen utilization in spinach (Spinacia oleracea L.). Nitrogen-modified nanobiochar was synthesized using ammonium chloride (NB-AC) and ammonium nitrate (NB-AN) at three nitrogen rates (0.03, 0.06, and 0.12 g N g−1 NB) and applied to soil at 1% (w/w). Soil properties, nutrient dynamics, and plant growth and physiological traits were analyzed after 15 and 30 days. Nitrogen modification significantly improved soil nitrogen retention and nutrient availability compared with unmodified nanobiochar. The highest nitrogen loading treatments (NB-AC3 and NB-AN3) notably improved spinach growth, photosynthetic efficiency, pigment content, nitrogen metabolism enzymatic activities, and accumulation of key metabolites (soluble sugars, flavonoids). Nitrogen-release assessments indicated a pronounced controlled-release with reduced nitrogen leaching and greater retention, particularly under NB-AN3. Overall, this study demonstrates that nitrogen-modified nanobiochar functions as an effective nitrogen carrier that enhances nitrogen utilization and growth. These findings provide mechanistic insights into its potential as a sustainable alternative to conventional nitrogen fertilizers.

Water deficit is a major constraint limiting the growth and yield of faba bean (Vicia faba L.). A pot experiment was conducted under controlled conditions to evaluate the effect of inoculation with Rhizobium leguminosarum bv. viciae BIHB 1148 (strain F14) and Pseudomonas alkylphenolica PF9 (strain L13) on faba bean drought resilience. Two irrigation regimes were applied: well-watered (80% of field capacity) versus water-stressed (40% of field capacity). Strain F14 was used to ensure effective biological nitrogen fixation, while strain L13 was applied in co-inoculation to evaluate its biostimulatory effects. The control plants received nitrogen in its chemical form. Results indicated that water deficit significantly (p < 0.001) reduced plant growth, nodulation, and photosynthesis-related parameters, and increased hydrogen peroxide (H2O2) and malondialdehyde (MDA) levels, which are key markers of oxidative stress. However, co-inoculation with strains F14 and L13 significantly enhanced shoot and root biomass, as well as most agro-morphological traits. It also stimulated (p < 0.05) the antioxidant activities of superoxide dismutase (3-fold), guaiacol peroxidase (12%), and catalase (104%), and increased proline content (119%), which led to lower levels of MDA (54% decrease) and H2O2 (55% decrease), improved membrane stability, water status, and enhanced photosynthesis. Overall, co-inoculation of faba bean with Rhizobium leguminosarum bv. viciae BIHB 1148 and Pseudomonas alkylphenolica PF9 offers a promising and sustainable approach to improve plant resilience under water deficit.

Burgeoning air pollution is a pressing public health concern. However, due to the scarcity and sparsity of ground-based monitoring, its impact remains uncertain. This work demonstrates how satellite-derived NO2 observations can identify persistent pollution hotspots and seasonal patterns in a data-scarce urban region. This work leveraged TROPOMI satellite data and Google Earth Engine to evaluate tropospheric NO2 hotspot patterns in the Greater Accra Region of Ghana from 2019 to 2023. TROPOMI data revealed persistent NO2 hotspots in urban and industrial areas, with overall peak concentrations reaching up to 3.3 × 1015 mol cm−2. Seasonal analysis showed elevated NO2 levels during the dry season, with a mean concentration of 2.3 × 1015 mol cm−2, while lower levels were observed during the rainy season. Increased emissions and reduced dispersion influence this pattern due to stable atmospheric conditions. Google Earth imagery confirmed that the highest NO2 concentrations were associated with the Heavy Industrial Area, highlighting the presence of extensive industrial facilities such as refineries, factories, and quarries. This integration of satellite observations with high-resolution geospatial tools provides a robust methodology for NO2 source attribution, emphasizing the need for targeted emission control measures in industrial zones to mitigate air pollution and associated health risks.

The identification of forage species with Biological Nitrification Inhibition (BNI) capacity is a promising strategy to inhibit soil nitrification and reduce nitrogen (N) losses. This study evaluated the BNI capacity of five Urochloa genotypes (Camello, Cayman, Marandú, Mulato II, Talismán) and their impact on biomass yield and nitrogen uptake (NU). The BNI capacity, biomass yield, N content, and NU of five Urochloa genotypes were compared. Significant differences in BNI capacity were observed between genotypes (p < 0.009). Cayman and Marandú presented the highest BNI values (87.41 and 87.21%, respectively), higher than those of Mulato II, Talismán and Camello (78.20, 81.77 and 82.63%, respectively). Regarding biomass yield, Cayman and Marandú stood out with 3093.5 and 2911.7 kg DM ha−1, respectively. Talismán and Camello showed higher N concentrations in the biomass (1.64 and 1.63%). In terms of NU, Cayman recorded the highest efficiency (47.32 kg N ha−1), surpassing Marandú, Camello, Talisman and Mulato II (42.83, 42.77, 41.53 and 37.23 kg N ha−1, respectively; p < 0.0001). BNI capacity influences biomass yield and nitrogen uptake. The Cayman genotype is positioned as a promising forage alternative for the development of more efficient and sustainable livestock systems by promoting more efficient N use.

Nitrogen deficiency is a major constraint on maize (Zea mays L.) productivity in Afghanistan, where poor soil fertility limits yields. This study investigated the effect of urea fertilizer on maize growth, physiology, and yield under semi-arid conditions in Balkh Province with a Calcisols soil type, focusing on maize cultivated for grain production. A field experiment was conducted in 2019 using a randomized complete block design with three replications and four nitrogen levels: 0 (control), 38.4, 76.8, and 115.2 kg ha−1. The region consists of fertile alluvial plains suitable for crop cultivation, though maize productivity is constrained by soil nutrient limitations, especially nitrogen deficiency. The soil at the experimental site is silty loam in texture, moderately fertile with alkaline pH (8.1), low organic matter (0.5%), and limited available nitrogen (15 mg kg−1). Growth traits (plant height, leaf number, leaf area, SPAD value), physiological parameters (leaf area index, crop growth rate, biomass), and yield components (cob length, cob diameter, seed number, 100-seed weight, biological yield, and Brix content) were recorded. Results showed that nitrogen application significantly improved all traits compared to the control. The highest values for plant height (260.2 cm), cob length (31.67 cm), biological yield (216.6 t ha−1), and Brix content (8.6%) were observed at 115.2 kg ha−1, although 76.8 kg ha−1 produced nearly similar results. Correlation analysis revealed strong positive associations between SPAD values, vegetative traits, and yield. The findings indicate that 115.2 kg ha−1 urea is an efficient and practical nitrogen rate for enhancing maize productivity under Afghan conditions.

Nitrogen is an essential element required for bacterial homeostasis. It serves as a building block for the biosynthesis of macromolecules and provides precursors for secondary metabolites. Actinomycetes have developed the ability to use various nitrogen sources to ensure their survival in ecological niches with fluctuating nutrient availability. A complex nitrogen metabolism of Actinobacteria allows the utilization of various compounds as N sources, including ammonium, nitrate, urea, amino acids, amino sugars, and amines. One such adaptation is the ability to acquire nitrogen from alternative amine sources like monoamines or polyamines putrescine, cadaverine, spermidine, and spermine, ensuring both nutrient availability (C and N sources) and resistance against high polyamine concentrations. Actinobacterial nitrogen degradation, including the catabolism of amines, is not only important under low nitrogen availability, but also required to survive under high concentrations of these compounds. The purpose of this review is to summarize the knowledge on nitrogen degradation and, more specifically, catabolism of amines in Actinobacterial survival and its role in nitrogen metabolism. Applying critical analysis of the recent available literature and sequencing data, this work aims to explore strategies of pathogenic and non-pathogenic Actinobacteria to survive in the presence of different nitrogen sources, and their impact on primary and secondary metabolism. The knowledge about nitrogen degradation pathways in Actinobacteria including mono- and polyamine catabolism collected in the scope of this review paper is brought in connection with possibilities to combat pathogens by using their capability to metabolize polyamines as an antibiotic drug target. This might offer new directions for target-based drug design to combat Actinobacterial infections.

The increasing biogeochemical imbalance of nitrogen (N) heightens the importance of studying rhizosphere bacteria, which aid crop nutrient uptake, and their responses to N deficiency. The aim of the study was to assess variety-specific responses of the tomatoes and their associated rhizobacteriome to low N availability. Three determinant varieties of Solanum lycopersicum L. were cultivated in pot-scale experiment during 10 weeks on low-fertility substrate (sod-podzolic soil:peat:clay:sand, 1:1:1:2, v/v), half of which were supplemented with ammonium nitrate (60 mg N kg−1 in total). A comprehensive methodology was employed, including 16S rRNA metagenomic Nanopore sequencing, quantitative assessment of N-cycling bacteria, and analysis of plant growth, photosynthetic pigments, total N in biomass, and fine root architecture. Results demonstrated that N deficiency significantly reduced plant biomass and photosynthetic pigments. The rhizosphere contained a diverse community of N-transforming bacteria (38 identified genera), whose composition and relative abundance were strongly influenced by both tomato variety and N fertilization. Nitrogen application increased the abundance of N-fixers and altered alpha-diversity in a variety-dependent manner. Significant correlations were found between the abundance of key bacterial genera (e.g., Stenotrophomonas, Rhizobium) and N parameters in plants and substrates. The study concludes that the response of the tomato rhizobacteriome to N availability is variety-specific, which is important for the development of microbiome management strategies for enhancing N use efficiency.