Nitrogen Use Research Articles

Exploring Nitrogen Use Efficiency in Cereals: Insight into Traits, Metabolism, and Management Strategies Under Climate Change Conditions – A Comprehensive Review

Exploring Nitrogen Use Efficiency in Cereals: Insight into Traits, Metabolism, and Management Strategies Under Climate Change Conditions – A Comprehensive Review

Closing economical and sustainability gaps for China's wheat, maize, and rice production: A county level energy analysis approach.

Closing economical and sustainability gaps for China's wheat, maize, and rice production: A county level energy analysis approach.

Nitrogen Supply Mitigates Temperature Stress Effects on Rice Photosynthetic Nitrogen Use Efficiency and Water Relations

Climate-change-induced temperature fluctuations pose significant threats to global rice production, particularly through their impact on photosynthetic efficiency. The differential mechanisms by which low and high temperatures affect leaf photosynthetic processes in rice remain poorly understood. Here, we investigate the effects of temperature stress (15 °C, 30 °C, 45 °C) on rice photosynthetic performance across a gradient of nitrogen supply levels: low nitrogen (LN), medium nitrogen (MN), and high nitrogen (HN). The low temperature exhibited stronger negative impacts on photosynthesis than the high temperature, primarily through increased mesophyll limitation and disrupted cellular CO2 diffusion, while the high temperature showed less pronounced effects, particularly under HN and MN conditions. While photosynthetic nitrogen use efficiency (PNUE) decreased with increasing nitrogen under the optimal temperature, moderate nitrogen supply maintained optimal PNUE under temperature stress, suggesting that a balanced nitrogen level is crucial for maximizing both photosynthetic capacity and nitrogen use efficiency. Plants with adequate nitrogen maintained higher intrinsic water use efficiency (iWUE) under both temperature extremes through improved coordination between CO2 uptake and water loss. Our findings reveal distinct mechanisms underlying low- and high-temperature stress effects on photosynthesis and highlight the importance of optimizing nitrogen management for enhancing crop resilience to temperature extremes under climate change.

Enhancing seed yield and nitrogen use efficiency of Brassica napus L. under low nitrogen by overexpression of G-proteins from Arabidopsis thaliana.

Heterotrimeric G-proteins, composed of Gα, Gβ, and Gγ subunits, are involved in the regulation of multiple signaling pathways in plants. OsDEP1 (Gγ subunit-encoded protein) of rice and TaNBP1 (Gβ subunit-encoded protein) of wheat are homologs of Arabidopsis AGG3 and AGB1, respectively, which are regulators of grain size and also involved in nitrogen responses. However, the function of Arabidopsis G-proteins in nitrogen utilization under different nitrogen conditions has not been fully investigated. In this study, to evaluate the role of Arabidopsis G-proteins towards yield and nitrogen use efficiency (NUE), overexpressing transgenic lines AtGPA1, AtAGB1 together with AtAGG1 (AGB1-AGG1), with AtAGG2 (AGB1-AGG2), and with AtAGG3 (AGB1-AGG3) were created in the "K407" Brassica napus (B. napus). Analysis of multiple transgenic B. napus lines showed that overexpression of GPA1, AGB1-AGG1, AGB1-AGG2, or AGB1-AGG3 increased the biomass of seedling plants including a well-developed root system and increased nitrogen uptake under low and high nitrogen conditions. The activity of glutamine synthetase (GS), a key nitrogen assimilating enzyme, as well as the expression levels of genes that are involved in nitrogen uptake and assimilation were significantly increased in overexpressing plants under low nitrogen conditions. These properties enabled overexpressing plants to increase the number of seeds per silique by 12%-27% only under low nitrogen condition, effectively improving yield per plant by 9%-69% and NUE by 7%-49%. These results reveal roles of G-proteins in regulating seed traits and NUE, and provide a strategy that can substantially improve crop yield and NUE.

Responses of cereals to nitrogen deficiency: Adaptations on morphological, physiological, biochemical, hormonal and genetic basis

Nitrogen (N) is a primary macronutrient essential for plant growth and development. Global nitrogen fertilizer consumption is approximately 120 million tons, with nitrogen use efficiency (NUE) ranging between 25 % and 50 %. Excessive use of nitrogen fertilizer poses significant risks to the envi ronment and living organisms, highlighting the need to reduce fertilizer ap plication, improve NUE, and sustain crop productivity. Sustainable agricul tural practices emphasize minimizing fertilizer usage. Therefore, developing high-NUE crop varieties capable of maintaining yields under reduced nitro gen input is critical for ensuring food security and protecting ecosystem. A promising strategy involves investigating plant responses to varying nitro gen levels, particularly under low-nitrogen conditions. This review explores the morphological, physiological, biochemical, hormonal, and genetic changes in cereals subjected to low-nitrogen conditions. Morphological adaptations include alterations in root and shoot architecture, while physi ological responses involve enhanced chlorophyll content, leaf nitrogen lev els, and photosynthetic efficiency. Biochemical changes are characterized by increased activity of nitrogen uptake and assimilation enzymes, accom panied by hormonal shifts such as elevated auxin levels in roots. These traits provide a foundation for developing nitrogen-efficient crop varieties. Future research should prioritize breeding crops with enhanced tolerance to low-nitrogen conditions to improve NUE, grain quality, and yield potential.

Evaluating the Adaptability and Sustainability of Different Straw Incorporation Strategies in Northeastern China: Impacts on Rice Yield Formation, Nitrogen Use Efficiency, and Temporal Soil Nutrient Dynamics

Straw incorporation effectively improves soil fertility and crop yield, and its adaptation to single-season rice production in cold temperate regions is a current research focus. This study conducted a two-year continuous in situ field experiment with four treatments: no straw incorporation (CK), straw incorporation with autumn rotary tillage (SC), straw incorporation with autumn plowing (SH), and straw incorporation with spring rotary tillage (ST). This study investigated the effects of straw incorporation on rice growth and the soil environment to understand the soil-crop interactions and their impact on rice yield. The results indicate that in the single-season rice production system of Northeast China, straw incorporation reduces the number of tillers, dry matter accumulation, and leaf area index in the early rice growth stage but promotes dry matter accumulation in the later stages. Straw incorporation over two consecutive years increased the rice yield by 2.07%, with the SC treatments showing optimal performance. This increased yield could lead to higher economic returns for the farmers. Additionally, straw incorporation potentially increases the total nitrogen and soil organic matter (SOM) content in the topsoil, thus providing environmental benefits by reducing the need for synthetic fertilizers. Factor analysis reveals that the SC treatments enhances dry matter accumulation by influencing soil nutrient levels in the later rice growth stages, thereby improving rice yield and nitrogen recovery efficiency. By altering soil nutrient availability at different growth stages, different straw incorporation regimes regulate the material production strategy of rice and the ‘source-sink’ relationship. This research provides a theoretical basis for enhancing soil fertility and rice yield in cold temperate regions through improved straw management strategies. These findings support policy initiatives that promote large-scale straw incorporation in commercial rice production for its potential economic and environmental benefits.

Nutrient balance and nutrient use efficiency in Japan

ABSTRACT This study aimed to evaluate the reactive nitrogen (Nr), phosphorus (P), and potassium (K) balance and use efficiency as the basics for crop fertilization management, soil fertility management, and indicator for potential of negative environmental impacts from 1980 to 2010. I categorized 70–100 crops listed in past statistics into seven crop categories (paddy rice, upland crops, vegetables, orchards, tea, forage, fodder). Individual documents from a national survey of farmland soil management, conducted six times from 1979 to 2012 by the Ministry of Agriculture, Forestry and Fisheries, Japan, were used to estimate Nr, P, and K application for the seven crop categories as chemical fertilizer and livestock manure. Production of Nr, P, and K were estimated from agricultural statistics and the Food Nutrition Standard. The balance of NrPK was defined as the application less production for the seven crops. Use efficiency of NrPK was defined as the application divided by the production for the seven crops. In general, vegetables and tea received significantly higher NrPK application than paddy rice, forage, and fodder. Forage and fodder NrPK production was significantly higher than for paddy rice and orchard crops. The balance of NrP was larger in vegetables, orchards, and tea than in paddy rice, upland crops, forage, and fodder, although the K balance was not significantly different between the seven crops because of the large variation in the K balance. The use efficiency of NrP was higher in paddy rice, upland crops, forage, and fodder than in vegetables, orchards, and tea because of the lower application and relatively higher NrP production, especially in forage and fodder. Use efficiency of K was higher in upland crops, vegetables, tea, forage, and fodder than in paddy rice and orchards because of the small K production of these crops. Lower application of NrPK would be a simple and easy strategy for crop production and soil fertility management; however, it would be more effective to incorporate crop physiology, nutrient demand, crop quality, soil NrPK condition, and prevention of excess intake of nutrients by crops. These practices would increase crop and soil health and would result in better soil security.

Effects of Long-Term Input of Controlled-Release Urea on Maize Growth Monitored by UAV-RGB Imaging

Maize is a critical crop for global food security, yet excessive nitrogen (N) application, while sustaining yields, leads to reduced nitrogen use efficiency (NUE), and the application of controlled-release fertilizer (CRF) is one of the effective options to achieve sustainable maize production while improving NUE. This study evaluated the long-term effects of CRF with varying N input rates on maize growth using low-cost UAV-RGB imaging. UAV-RGB images were captured in different growth stages, and the non-canopy background was removed using the maximum between-class algorithm (OTSU). Eleven vegetation indices were constructed from the images to analyze maize growth under different N treatments. The results indicated that a single application of CRF with an equivalent N input rate to conventional treatment yielded significantly better outcomes. The optimal controlled-release N ratio was 40% of the total N input, increasing maize yield by 6.73% and NUE by 15%. Indices such as NRI, NBI, ARVI, RGBVI, ExR, ExG, and ExGR effectively reflected plant N status, with R2 values exceeding 0.856 for yield estimation across growth stages. UAV-RGB imaging proved to be a viable method for rapid N status monitoring, aiding in the optimization of N management in maize production.

Optimizing nitrogen delivery: Controlled release of fertilizer using mesoporous silica for sustainable agriculture

This study investigates the potential of mesoporous silica as a controlled-release medium for nitrogen fertilizers. Mesoporous silica was synthesized using the sol-gel method with cetyltrimethylammonium bromide (CTAB) as a template, followed by surface modification and calcination to obtain silica gel, surface-coated silica, and calcined silica. Structural analysis using FTIR confirmed that calcined silica exhibited a highly condensed network with minimal surface hydroxylation, while surface-coated samples retained organic groups. Nitrogen adsorption–desorption studies revealed that silica gel had the highest adsorption capacity (35%) but also a relatively high desorption rate (1.75%), leading to faster nutrient release. Surface-coated silicas exhibited lower adsorption efficiencies (20% and 25%) with desorption rates of 2% and 1.5%, respectively. Calcined silica had the lowest adsorption (15%) but also the lowest desorption (<1%), indicating a more controlled release. Nitrogen release testing confirmed this trend, with calcined silica showing the slowest release rate, reaching only 396.8 ppm by Day 6. These findings highlight calcined mesoporous silica as a promising material for enhancing nitrogen use efficiency in agriculture while minimizing environmental losses.

Characterization of N variations in different organs of winter wheat and mapping NUE using low altitude UAV-based remote sensing

Although unmanned aerial vehicle (UAV) remote sensing is widely used for high-throughput crop monitoring, few attempts have been made to assess nitrogen content (NC) at the organ level and its association with nitrogen use efficiency (NUE). Also, little is known about the performance of UAV-based image texture features of different spectral bands in monitoring crop nitrogen and NUE. In this study, multi-spectral images were collected throughout different stages of winter wheat in two independent field trials - a single-variety field trial and a multi-variety trial in 2021 and 2022, respectively in China and Germany. Forty-three multispectral vegetation indices (VIs) and forty texture features (TFs) were calculated from images and fed into the partial least squares regression (PLSR) and random forest (RF) regression models for predicting nitrogen-related indicators. Our main objectives were to (1) assess the potential of UAV-based multispectral imagery for predicting NC in different organs of winter wheat, (2) explore the transferability of different image features (VI and TF) and trained machine learning models in predicting NC, and (3) propose a technical workflow for mapping NUE using UAV imagery. The results showed that the correlation between different features (VIs and TFs) and NC in different organs varied between the pre-anthesis and post-anthesis stages. PLSR latent variables extracted from those VIs and TFs could be a great predictor for nitrogen agronomic efficiency (NAE). While adding TFs to VI-based models enhanced the model performance in predicting NC, inconsistency arose when applying the TF-based models trained based on one dataset to the other independent dataset that involved different varieties, UAVs, and cameras. Unsurprisingly, models trained with the multi-variety dataset show better transferability than the models trained with the single-variety dataset. This study not only demonstrates the promise of applying UAV-based imaging to estimate NC in different organs and map NUE in winter wheat but also highlights the importance of conducting model evaluations based on independent datasets.

Sphingobium yanoikuyae 41R9 Enhances Nitrogen Uptake by Modulating Transporter Genes and Root Development in Rapeseed.

Plant growth-promoting rhizobacteria (PGPR) are widely recognized for enhancing the absorption of mineral nutrients by crops. While Sphingobium species have been reported as PGPRs, their capacity to improve nitrogen use efficiency (NUE) and the underlying regulatory mechanisms are not yet fully understood. Here, a strain 41R9, isolated from the rhizosphere of N-deficient rapeseed, was found to significantly enhance the growth performance of rapeseed under both low and normal N conditions. Genomic analysis revealed that strain 41R9 was closely related to Sphingobium yanoikuyae. 15N isotope tracer experiments confirmed that inoculation with strain 41R9 significantly boosted N uptake and translocation in rapeseed roots. Transcriptome profiling demonstrated that strain 41R9 directly upregulated N transporter genes (NRT2.5and SLAH1/3), facilitating efficient N acquisition. Furthermore, strain 41R9 maintained jasmonic acid (JA) homoeostasis via JAZ-mediated negative feedback, balancing defense responses and root development, thereby improving the plant's N acquisition capacity in the roots. Metabolomic and in vitro assays further demonstrated that strain 41R9 displayed strong chemotaxis towards kaempferol, a N-deficiency-induced root exudate, suggesting kaempferol might as a chemical effector for S. yanoikuyae recruitment. These findings advance our understanding of PGPR-driven mechanisms in enhancing crop NUE and highlight the potential of harnessing PGPRs for sustainable agriculture.

Rice Yield and Nitrogen Use Efficiency Under Climate Change: Unraveling Key Drivers with Least Absolute Shrinkage and Selection Operator Regression

Rice (Oryza sativa L.), a staple crop vital to global food security, faces escalating threats from climate change and inefficient nitrogen management. This study employed least absolute shrinkage and selection operator (LASSO) regression to analyze the stage-specific impacts of nitrogen application, temperature, and rainfall on rice yield and nitrogen use efficiency (NUE) across three growing seasons (2020–2022) in Jiangsu Province, China. The key findings revealed the following: (1) the reproductive stages (flowering and filling stages) exhibited extreme thermal sensitivity, with high temperatures (&gt;35 °C) causing substantial yield losses (33.1% average) and reducing nitrogen recovery efficiency (NRE: 22.4–60.5% loss) and the nitrogen translocation ratio (NTR: 26.3–61.6% loss); (2) the vegetative stages (tillering and jointing and booting stages) were highly rainfall-sensitive, with rainfall during tillering (2.1–9.7 mm/day) influencing 50% of the traits, including four NUE types; (3) appropriate nitrogen management (250–350 kgN·ha−1) mitigated the heat-induced losses, increasing physiological nitrogen use efficiency (PNUE) by 30.0–41.8% under extreme heat and alleviating the losses of yield. This study further verified the generalizability of LASSO. Compared with the traditional models, LASSO overcomes the issue of multicollinearity and can more effectively identify the key factors driving climate change across different spatial gradients. These findings provide actionable insights for optimizing nitrogen application timing, improving climate-resilient breeding, and developing stage-specific adaptation strategies to safeguard rice productivity under global warming.

Enhancing nitrogen use efficiency in agriculture by integrating agronomic practices and genetic advances

Nitrogen is a critical nutrient for plant growth and productivity, but inefficiencies in its use in agriculture present both economic and environmental challenges. Enhancing nitrogen use efficiency (NUE) is essential for promoting sustainable crop production and mitigating the negative impacts of nitrogen loss, such as water pollution and greenhouse gas emissions. This review discusses various strategies aimed at improving NUE, with a focus on agronomic practices, genetic advancements, and integrated management approaches. Traditional agronomic methods, including split nitrogen application and the use of controlled-release fertilizers, are explored alongside precision agriculture techniques, which enable real-time adjustments to nitrogen application based on crop and soil conditions. Advances in genetics and biotechnology, such as conventional breeding, genetic modification, and genome editing, have contributed to the development of crop varieties with improved nitrogen uptake and assimilation. Additionally, the role of beneficial microbes, including nitrogen-fixing bacteria and mycorrhizal fungi, is highlighted as a natural means of enhancing nitrogen availability and reducing reliance on synthetic fertilizers. The review further emphasizes sustainable practices such as legume-based crop rotations, continuous cover cropping, and organic fertilization, which contribute to soil nitrogen enrichment and overall soil health. By combining these agronomic, genetic, and microbial strategies, a holistic nitrogen management approach can be achieved, maximizing crop yields while minimizing environmental impacts. This integrated strategy supports the development of resilient and sustainable agricultural systems, promoting long-term soil fertility and productivity.

MiRNA-seq analysis revealed a potential strategy underlying poplar root responses to low nitrogen stress.

87 miRNAs responding to low nitrogen stress in poplar roots were identified by miRNA-seq, and their target genes were predicted. Additionally, several key miRNA-mRNA modules were summarized. Nitrogen (N) is an essential nutrient for plants, and low nitrogen (LN) availability can constrain plant growth and development. MicroRNAs (miRNAs) play an important role in plant response to nutrient stress as a regulatory factor. However, studies on the function of poplar miRNAs under LN stress are limited. In this study, we investigated the potential role of miRNA in poplar roots under LN stress using miRNA-seq. 305 conserved miRNAs belonging to 48 miRNA families were identified, and 15 novel miRNAs were predicted. Among these, 83 known miRNAs from 21 families and 4 novel miRNAs were confirmed as differential expressed miRNAs (DEMs) following LN stress treatment at 6, 9, 24, 72, 240, and 504h compared to 0h. Functional annotation analysis indicated that an array of miRNAs, including miR160, miR172, and miR166, should be involved in LN stress. TargetFinder and psRobot predicted that 52 of these miRNAs target 248 genes, resulting in 319 miRNA targeting pairs. Degradome sequencing further revealed that these 52 miRNAs targeted 457 genes, with 358 miRNA-target pairs. Gene annotation of target genes indicated that AP2, ARF, HD-ZIP, and other genes might respond to LN stress by regulating root growth and development. These findings provide valuable insights into miRNA functions and establish a framework for further investigating miRNA-mediated N signal transduction networks under LN stress. This research may offer new perspectives for genetic engineering to enhance nitrogen use efficiency in forest trees.

Influence of Inoculant Application Methods on the Physiological Quality of Common Bean Seeds

Common bean (Phaseolus vulgaris L.) is one of Brazil&amp;rsquo;s main crops, however, its productivity remains low. Biological nitrogen fixation (BNF) is a sustainable alternative to mineral nitrogen fertilization, reducing costs and environmental impacts. This study aimed to evaluate the physiological quality of BRS Estilo bean seeds under different inoculation strategies with Rhizobium tropici. The experiment was conducted during the 2022/2023 growing season in An&amp;aacute;polis-GO, using six treatments: seed inoculation, furrow inoculation, topdressing reinoculation at the V4 stage, their combinations, as well as a mineral nitrogen fertilization treatment and a control without nitrogen. The harvested seeds were subjected to germination, vigor, accelerated aging, seedling length, and dry mass tests. The results indicated that furrow inoculation combined with topdressing reinoculation at the V4 stage produced higher-quality seeds, with germination and vigor comparable to those of mineral nitrogen fertilization. Conversely, single seed inoculation was insufficient to ensure high quality seeds. It was concluded that furrow inoculation followed by topdressing reinoculation can partially or fully replace mineral nitrogen fertilization, improving nitrogen use efficiency in common bean and contributing to a more sustainable production system.

Impact of Irrigation Regimes and Nitrogen Fertilizer on Grain Yield, Water and Nitrogen Use Efficiencies of Winter Wheat Varieties Released Between 1950 and 2020

Impact of Irrigation Regimes and Nitrogen Fertilizer on Grain Yield, Water and Nitrogen Use Efficiencies of Winter Wheat Varieties Released Between 1950 and 2020

Nitrous Oxide Production and Mitigation Through Nitrification Inhibitors in Agricultural Soils: A Mechanistic Understanding and Comprehensive Evaluation of Influencing Factors

Nitrous oxide (N2O) is a potent greenhouse gas, and agriculture represents more than fifty percent of total anthropogenic emissions. The production of N2O in soil is biogenic through nitrification, denitrification, chemonitrification, nitrifier denitrification, etc., which are processes influenced by the soil pH, temperature, moisture, oxygen concentration, organic carbon, and soil nitrogen. Higher N2O emissions from the soil result in lower nitrogen use efficiency and higher environmental pollution in terms of global warming. Therefore, an understanding of different pathways for N2O production in soil and the affecting factors is essential to mitigate N2O emissions from soil to the atmosphere. Nitrification inhibitor application has been reported in many studies, but the impact of nitrification inhibitors in different perennials (orchards) and biennials (rice, wheat, maize, etc.) is not lacking. In this study, we develop an understanding of different N2O production pathways and different influencing factors. The role of the different nitrification inhibitors was also developed to achieve low N2O emissions from soils to the atmosphere.

Genome-wide identification of invertase genes in sweetpotato and its response to nitrogen and planting densities

BackgroundInvertases (INVs) included CWIN, CIN and VIN, are key enzymes in sucrose hydrolysis into glucose and fructose and essential for plant root development. Yet the effects of nitrogen and planting density on IbINVs expression remains unexplored in sweetpotato.ResultsThis study identified 22 invertase (IbINV) genes in the sweetpotato genome and conducted comprehensive analyses of their subcellular localization, gene structure, and conserved motifs and domains. Gene Ontology functional and protein interaction network analysis suggested that IbCWIN1/2/5/6 potentially interact with HKL1/3, HXK2/3/4, and other proteins, significantly influencing carbohydrate metabolic functions and biological processes in sweetpotato. Transcriptome data revealed that IbCIN2 and IbVIN3 were highly expressed in fibrous root (FR) and potential storage root (PSR), while IbVIN4 exhibited high expression levels in storage roots (SR), and IbCWIN2 was highly expressed in both FR and SR. Moreover, the field experiments demonstrated that, compared with EN (180 kg N ha-1) combined with LD (50,000 plant ha− 1), MN (120 kg N ha− 1) combined with MD (62,500 plant ha− 1) enhanced storage roots number and weight. Notably, compared with LDEN treatment, IbCIN2, IbCWIN2, IbVIN3 and IbVIN4 under MDMN treatment were significantly upregulated, extremely significant differences at 15DAP, of which IbCIN2 showed a maximum of 23.24-fold change, showing a positive correlation with increased INV enzyme activity, glucose (GLc), and fructose (FRc) content. Additionally, screening of homologous genes showed that IbCIN2 is homologous to AtA/N-INVI and AtA/N-INVG, IbCWIN2, IbVIN3 and IbVIN4 are homologous to VACUOLAR, INVERTASE1 and BFRUCT4, with similar functions, further supporting their involvement in storage root formation and development.ConclusionThese observations underscore the expansion of IbINVs in sweetpotato and provide a theoretical basis for optimizing the interaction between nitrogen application and planting density in sweetpotato, allowing for more efficient nitrogen use and improved growth.

Sexual Dimorphism in Nitrogen Allocation Patterns of Fraxinus velutina Torr. Across Developmental Stages

This study investigates the effects of gender and developmental stage on photosynthetic nitrogen allocation in 10-year-old Fraxinus velutina Torr. focusing on photosynthetic nitrogen and leaf nitrogen. The results reveal significant differences in photosynthetic nitrogen allocation patterns between genders and developmental stages (p &lt; 0.05 for gender, p &lt; 0.01 for developmental stages). Male trees generally exhibit higher photosynthetic nitrogen use efficiency (PNUE) and photosynthetic rate (Pphot) than female trees. However, female trees allocate more nitrogen to photosynthetic processes (Rubisco and bioenergetics) during fruit expansion to compensate for reproductive costs. This study highlights that gender and developmental stage influence leaf nitrogen partitioning and PNUE, with distinct nitrogen requirements for males and females across developmental stages.

Rhizosphere-associated bacterial and fungal communities of two maize hybrids under increased nitrogen fertilization.

The selection and application of nitrogen-efficient maize hybrids have significantly bolstered contemporary food security. Nevertheless, the effects of heightened nitrogen fertilizer demand of these crops on the composition and assembly of soil microbial communities in agricultural production require further elucidation. In this study, the effects of four nitrogen fertilizer managements on rhizosphere bacterial and fungal community assembly, co-occurrence network and function of two maize hybrids (LD981 and DH605) were compared. Findings revealed that the bacterial community was primarily shaped by deterministic processes, while stochastic processes played a pivotal role in fungal community assembly. N-efficient hybrid DH605 had a more stable microbial network than N-inefficient hybrid LD981. At N3 (130 g N/m2) rate, the bacterial and fungal community networks were the most complex but unstable, followed by N2 (87 g N/m2), N0 (0 g N/m2), and N1 (43 g N/m2) rates. Excessive nitrogen rate (N3) increased the relative abundance of denitrification genes nirK and norB by enriching nitrogen-related genus such as Nitrolancea and Nitrosospira. It led to an increase in the relative abundance of pathways such as cysteine and methionine metabolism and pyruvate metabolism. The effects of management practices (i.e. maize hybrids and N rates) on microbial communities were ultimately directly or indirectly reflected in microbial functions. Our findings illustrate the relationship between the appropriate selection of crop hybrids and management measures in optimizing rhizosphere microbial community assembly and promoting nitrogen use, which is necessary for sustainable food security.