Wheat (Triticum aestivum L.) is one of the most widely cultivated cereal crops worldwide and serves as a principal staple food for a substantial proportion of the global population. It is a self-pollinated, hexaploid species (2n = 42) belonging to the family Poaceae and is well adapted to diverse agro-climatic conditions as an annual long-day C₃ crop. Wheat contributes nearly 20% of the total dietary calories and protein intake globally, underscoring its critical role in food and nutritional security (Alkhader, 2023; Choudhary et al., 2023). According to the Food and Agriculture Organization (FAO, 2025), global wheat production is projected to reach 809.7 million tonnes, while India’s wheat production is estimated at a record 117.5 million tonnes during 2025-26, reflecting gains achieved through improved cultivars and agronomic management (FAO GIEWS, 2025).
       
Despite these advances, sustaining wheat productivity remains challenging due to declining soil fertility and low nutrient-use efficiency of conventional fertilizers. Typically, only 30-50% of applied nitrogen and 10-25% of phosphorus is utilized by crops, with substantial losses through leaching, volatilization and fixation, leading to environmental pollution and soil degradation (Syed et al., 2024; El-Sorady et al., 2022). Balanced nutrition involving nitrogen, phosphorus, potassium and micronutrients such as zinc and iron is essential for optimal wheat growth, photosynthesis and grain quality; however, inefficiencies in fertilizer delivery often limit their effective utilization (Pandey et al., 2020; Shri et al., 2024).
       
Nano-fertilizers have emerged as a promising alternative to conventional fertilizers owing to their small particle size, higher surface area and controlled nutrient release, which enhance nutrient availability, uptake efficiency and crop performance while minimizing losses (Singh et al., 2023; Babu et al., 2024). When used in combination with conventional fertilizers, nano-fertilizers have been reported to improve plant growth, nutrient uptake and yield, while reducing environmental hazards associated with excessive fertilizer use (Fatima et al., 2021). Among different application methods, foliar application of nano-fertilizers is particularly effective, as it allows direct nutrient absorption through leaves and ensures rapid physiological response by plants (Marzouk et al., 2019).
       
In addition to nano-fertilizers, biofertilizers such as Azotobacter play a crucial role in sustainable nutrient management. Azotobacter is a free-living nitrogen-fixing bacterium that enhances nitrogen availability, synthesizes plant growth-promoting substances and improves soil organic carbon, thereby contributing to improved crop growth, yield and soil fertility (Kantwa et al., 2025; Pandove et al., 2025; Saikia et al., 2018). Previous studies have shown that integrated use of nano-phosphatic fertilizers and organic or biological inputs can enhance nutrient-use efficiency, grain protein content and mineral composition in wheat (Patil et al., 2020; Pandey et al., 2025).
       
Although the individual effects of nano-fertilizers and Azotobacter on wheat productivity have been reported, systematic information on their combined influence on nutrient content, uptake, grain quality and post-harvest soil fertility under semi-arid conditions is limited. In particular, their potential to reduce chemical fertilizer requirements without compromising productivity under the agro-climatic conditions of southern Haryana remains insufficiently explored.
       
Therefore, the present study was undertaken to evaluate the combined effect of nano-fertilizers and Azotobacter on nutrient content and uptake, grain quality parameters and soil fertility status of wheat (Triticum aestivum L.) under southern Haryana conditions.

A field experiment was conducted during the Rabi season 2023-24 at the Agronomy Research Farm, SGT University, Gurugram, Haryana. The cropping season experienced favourable weather conditions for wheat cultivation with a total rainfall of 156.1 mm, primarily during the 6^th, 13^th and 14^th meteorological weeks. The temperature ranged from 3.0°C to 38.4°C (Visual Crossing, 2023). The randomized block design (RBD) with three replications ensured statistical reliability and minimized experimental error. The study comprised seven treatment combinations: T₁ Control (No fertilizer application), T₂ (100% Recommended Dose of Fertilizers, 120:60:40 kg ha^-1), T₃ (100% RDF + Azotobacter), T₄ (75% RDF + Azotobacter + FS of Nano Urea at CRI and flowering stage + FS of Nano DAP at booting and flowering stage), T₅ (50% RDF + ST (Nano Urea + Nano DAP) + FS of Nano Urea at CRI stage + FS of Nano DAP at pre flowering stage), T₆ (50% RDF + ST (Nano-Urea + Nano DAP) + FS of Nano Urea at CRI stage and flowering stage + FS of Nano DAP at CRI and flowering stage), T₇ ( ST (Nano-Urea + Nano DAP) + FS of Nano Urea at flowering stage + FS of Nano DAP at CRI and flowering stage). Wheat seeds of variety HD 2967 were treated with Nano Urea and Nano DAP (4 ml kg^-1 each) and Azotobacter (5 ml kg^-1), shade-dried for 30-45 minutes and sown on November 13, 2023, at a seed rate of 100 kg ha^-1 with 22.5 cm row spacing. Foliar sprays (4 ml L^-1) were applied at tillering, booting, pre-flowering and flowering stages. Each 3 × 3 m plot followed all recommended agronomic and plant protection practices.
       
Soil samples collected from the 0-15 cm depth were analysed for soil fertility. Soil pH (1:2 suspension) was measured following (Piper, 1996; Jackson, 1973), electrical conductivity (EC) using a conductivity bridge (Richards, 1954) and organic carbon (%) by the Walkley and Black wet oxidation method (Jackson, 1973). Available nitrogen was determined by the alkaline permanganate method (Subbiah and Asija, 1956), available phosphorus by Olsen’s method (Olsen et al., 1954) and available potassium using a flame photometer (Jackson, 1973). The nitrogen content in grains and straw was analysed by the Nessler’s reagent method (Jackson, 1973) and protein content was calculated by multiplying nitrogen percentage by 6.25 (Prasad et al., 2006). Phosphorus content was estimated using the vanado-molybdate yellow colour method and potassium content by flame photometry (Jackson, 1973). Nutrient uptake, expressed in kg ha^-1, represents the total N, P and K absorbed by wheat (grains and straw) and is calculated as (Rathore et al., 2023).

Wheat grain purity (%) was determined from a 100g sample by separating bold, thin and infested grains using a 2.0 mm sieve, with infested grains visually identified and weighed (ISTA, 2015; Agrawal, 1995).

Nutrient content and uptake in wheat
 
Different nutrient management treatments significantly influenced nitrogen, phosphorus and potassium content and their uptake in wheat grain and straw (Table 1). Nitrogen content in grain was highest under T₃, whereas straw nitrogen content and total nitrogen uptake were maximized under T₃ (100% RDF + Azotobacter). The enhanced nitrogen availability under Azotobacter inoculation can be attributed to biological nitrogen fixation and improved root growth, which enhanced nutrient absorption. These findings corroborate earlier reports (Kannoj et al., 2022; Upadhyay et al., 2023; Obour et al., 2023).


       
Phosphorus and potassium contents in both grain and straw, as well as their total uptake, were significantly higher under T₃, followed closely by T₄. The superior performance of integrated treatments may be attributed to improved nutrient solubilization by Azotobacter and enhanced nutrient absorption efficiency through nano-fertilizer application. Similar trends have been reported by (Bhukya et al., 2024; Kannoj et al., 2022; Gawdiya et al., 2025; Abisankar et al., 2024).
       
Importantly, T₄ (75% RDF + Azotobacter + FS of Nano Urea at CRI and flowering stage + FS of Nano DAP at booting and flowering stage recorded nutrient uptake values statistically comparable to T₃, indicating that a 25% reduction in chemical fertilizer application did not compromise nutrient acquisition.
 
Grain quality parameters
 
Grain quality parameters were significantly influenced by nutrient management practices (Table 2). The highest proportion of bold grains and absence of infested grains were observed under T₃ and T₄, reflecting improved assimilate translocation and grain filling under integrated nutrient management. Treatments receiving Azotobacter and nano-fertilizers recorded lower proportions of thin and infested grains compared to the control. These results are consistent with earlier findings reported by (Khalid et al., 2023; El-Sorady et al., 2022).


 
Protein content
 
Protein content ranged from 9.00% in the control to 10.95% under T₃. Although differences among treatments were statistically non-significant, higher protein content under integrated treatments can be attributed to improved nitrogen availability during grain development. Similar observations were reported by (Kannoj et al., 2022; Singh, 2017).
 
Soil fertility status
 
Soil physico-chemical properties were moderately influenced by different treatments (Table 3). Soil pH and EC remained within permissible limits, indicating no adverse effect of nano-fertilizers or Azotobacter application. Organic carbon content was significantly higher under T₄, both at 30 DAS and after harvest, suggesting improved microbial activity and carbon sequestration under integrated nutrient management.


       
Available nitrogen, phosphorus and potassium were consistently higher under treatments receiving Azotobacter and nano-fertilizers, particularly T₃ and T₄. Enhanced nutrient availability may be attributed to biological nitrogen fixation, improved nutrient solubilization and reduced nutrient losses. These findings are in agreement with earlier studies (Gajraj et al., 2023; Kantwa et al., 2025; Ramya et al., 2022).

The present study demonstrated that integrated application of nano-fertilizers and Azotobacter significantly improved nutrient content, nutrient uptake, grain quality and soil fertility in wheat under the semi-arid conditions of southern Haryana. The treatment comprising 100% RDF + Azotobacter recorded the highest values for nutrient uptake and quality parameters. However, 75% RDF combined with Azotobacter and nano-fertilizer foliar application performed comparably, indicating that chemical fertilizer use can be reduced by 25% without compromising crop productivity or quality. Enhanced soil organic carbon and nutrient availability further confirm the sustainability of this approach. Therefore, integration of nano-fertilizers with Azotobacter represents an eco-friendly and efficient nutrient management strategy for sustainable wheat production.

I sincerely thank Dr. Sucheta Dahiya for her guidance and support and express my gratitude to the Dean, faculty, staff, friends and my family for their constant encouragement throughout my research journey.
 
Disclaimer
 
The views and conclusions are solely those of the authors, not the affiliated institutions. Although accuracy is ensured, the authors bear no responsibility for consequences arising from the use or interpretation of this material.
 
Informed consent
 
All procedures followed institutional ethical standards with required consents and approvals obtained. No human or animal subjects were harmed, ensuring full compliance with ethical and regulatory guidelines.

The authors declare no financial or personal conflicts of interest. The research was conducted independently without external funding and all aspects were completed under the sole responsibility of the authors.