Wheat (Triticum aestivum L.) is a major cereal crop and a major source of energy and protein for a significant proportion of the world’s population.  Improvement of wheat production is crucial to address the increasing food demand due to population growth and food habits. Fertilisation, particularly nitrogen, is critical for the growth, development and yield of wheat (Jithendar et al., 2024). As a key macronutrient, nitrogen plays vital roles in physiological processes such as photosynthesis, protein synthesis and enzyme activity, thereby influencing crop growth and productivity (Kapri et al., 2025). Organic fertilisers, including farmyard manure (FYM) and poultry manure, play an important role in sustainable agricultural production by improving nutrient availability and contributing to soil fertility. These manures supply macro- and micronutrients and can enhance nutrient supply and retention (Kavinder et al., 2019; Natarajan, 2020). FYM is known to increase soil organic matter and water-holding capacity, where poultry manure tends to have a higher nutrient content and mineralisation is relatively fast, which may make the nutrients more readily available to growing crops (Kalappanavar and Gali, 2018; Kumar and Pareek, 2022).
       
Although conventional nitrogen fertilisers such as urea are commonly employed to enhance wheat productivity, nitrogen losses via volatilisation, leaching and denitrification can lower nitrogen-use efficiency (Jithendar et al., 2024). Nano-urea is a foliar nitrogen-management option that has been developed with the advancement of fertiliser technology and has the potential to increase NUE and can be used in combination with conventional nitrogen fertilisation (Tiwari, 2023). The use of organic manures and nitrogen fertilisers together can be complementary sources of nutrients and enhance nutrient availability, crop growth and yield (Rehim et al., 2020). This integrated nutrient management can help in the efficient utilisation of nutrients and sustainable crop production (Antil and Raj, 2020; Reddycherla et al., 2026).
       
Although the use of organic manures and nitrogenous fertilisers is known to be beneficial for wheat production, there is a lack of field-based information on the combined effects of various levels of farmyard manure (FYM) and poultry manure with conventional nitrogen and foliar nano-urea application under the agro-climatic conditions of Punjab. Specifically, the comparative effect of to various organic manure to wheat in conjunction with full or partial soil applied nitrogen and nano-urea sprays is poorly documented. Assessing these combinations is crucial for evaluating the possibility of reducing conventional nitrogen application while supplementing with foliar nano-urea under integrated nutrient management to sustain wheat growth and productivity. Hence, the present two-year field experiment was conducted to assess the effects of FYM and poultry manure along with various nitrogen-management practices on the  growth and productivity of wheat.
       
The specific objectives of the study were to (i) evaluate the effect of FYM and poultry manure on growth and productivity of wheat, (ii) assess the effect of various nitrogen management strategies on wheat growth and productivity using conventional recommended nitrogen and nano-urea as foliar supplements and (iii) determine the interaction between organic manure and nitrogen management on wheat growth and yield. The hypothesis was that the integrated application of organic manure with an appropriate nitrogen management strategy would improve wheat growth and productivity compared with the control,and that partial substitution of soil-applied nitrogen with foliar nano-urea would affect wheat productivity under reduced soil-applied nitrogen input.

Location and climate
 
The study was conducted for two years at the Research Farm of Lovely Professional University, School of Agriculture, Phagwara, Punjab, India, in the rabi seasons of 2023-2024 and 2024-2025. The research site is located in the Trans-Gangetic Plains at 31°14'36.11"N latitude and 75°04'49.89"E longitude at an altitude of 245 m above mean sea level. The area has a semi-arid subtropical climate with hot summers and cold winters and receives an average annual rainfall of 500-800 mm, most of it during the monsoon season (July-September). The experimental site soil was sandy loam in texture with initial pH of 7.60, organic carbon of 0.48%, available nitrogen, phosphorus (P₂O₅) and potassium (K₂O) of 183.63, 26.10 and 199.96 kg ha^-1, respectively.
 
Experimental details
 
The wheat cultivar PBW 824 (Punjab Agricultural University, Ludhiana) was used in the present study. Wheat was cultivated during rabi crop season using normal agronomic practices. The field was harrowed twice using a cross harrow and levelled to create a fine seedbed. The recommended seed rate of 100 kg ha^-1 was used for  sowing by hand in rows 20 cm apart. Five organic manure levels (Control, FYM 10 t ha^-1, FYM 15 t ha^-1, poultry manure 5 t ha^-1 and poultry manure 7.5 t ha^-1) were allotted to the main plots and three nitrogen levels [N₁: 100% RDN (125 kg N ha^-1); N₂: 50% RDN (62.5 kg N ha^-1) + two nano-urea foliar sprays at the tillering and booting stages; N₃: 75% RDN (93.75 kg N ha^-1) + one nano-urea foliar spray at the booting stage] were allotted to the sub-plots in a split-plot design with three replications, giving 15 treatment combinations and 45 plots in total. The size of each plot was 5 m × 3 m (15 m²) with 0.5 m bunds and 1.0 m irrigation channels between the plots.
 
Fertiliser and nano-urea management
 
Urea was used as the source of conventional nitrogen. Phosphorus and potassium were applied uniformly to all treatments at 62 kg P₂O₅ ha^-1 as single superphosphate (SSP) and 30 kg K₂O ha^-1 as muriate of potash (MOP). The main plots were fertilised with farmyard manure (FYM) containing 0.5% N, 0.5% P₂O₅  and 0.5% K₂O and poultry manure containing 3.63% N, 2.73% P₂O₅  and 1.4% K₂O according to the treatments. The nutrient content of FYM was reported on a dry matter basis, with nutrient concentrations being a percentage of dry matter, as recommended for organic manure characterization. FYM was incorporated three weeks before sowing, while poultry manure was incorporated two weeks before sowing. Nano-urea was sprayed as a foliar spray at 4% concentration with 500 L water ha^-1. N₂ received two applications of nano-urea at tillering and booting stages, while N₃ received one application at the booting stage. The crop received a pre-sowing irrigation followed by six irrigations at the crown root initiation, tillering, jointing, booting, flowering and dough stages.
 
Data acquisition and evaluation
 
Growth parameters
 
Plant height was measured at 90 DAS on five randomly tagged plants per plot, from the soil surface to the tip of the flag leaf during the vegetative phase and to the tip of the spike after spike emergence. Dry matter accumulation was determined at 60 DAS by destructive sampling, oven-drying and weighing of tagged plants. Leaf area index was measured at 60 DAS on a sample of leaves using a leaf area meter, following Watson (1947) formula:

 
Grain output and biomass yield
 
The entire gross plot (5 m × 3 m, 15 m²) was harvested for each treatment; the grains of each plot were threshed, cleaned and weighed and the values were converted to q ha^-1. The straw yield was determined as the difference between the total biological yield and grain yield (Singh and Stoskopf, 1971) and all yields were reported in q ha^-1. The biomass of each plot was air-dried under natural sunlight and weighed using a spring balance to obtain the biological yield, which was also converted to q ha^-1.
 
Statistical analysis
 
The data obtained in the two years were analysed using analysis of variance (ANOVA) for a split-plot design (Gomez and Gomez, 1984) at 5% level of significance using the OPSTAT computer program. The homogeneity of the error variances of the two years’ data was tested and the pooled data of the two years are presented as the error variances were found homogeneous. The critical difference (CD) and standard error of the mean (SEm ±) were used to determine treatment effects. The split-plot ANOVA allowed the assessment of the main effects of organic manures (main-plot factor) and nitrogen management (sub-plot factor, 100% RDN or reduced RDN with nano-urea foliar sprays) and their interaction (M × N) on growth characters, yield components and grain and straw yield. A split-plot design with three replications was used for the experiment. The main plots were treated with organic manures and the subplots with nitrogen treatments. Thus, organic manure (M) was tested against the main-plot error, whereas nitrogen (N) was tested against the subplot error. Analysis was carried out using the proper error structure of the split-plot design. Data for each year were analysed separately and the treatment ranking was similar for both years for all yield parameters. No attempt was made to formally test the year and year × treatment effects over the two years combined and no claim of significance or non-significance is made for year × treatment interactions in this manuscript.

Growth parameters
 
Plant height (cm)
 
The tallest plants were recorded at 90 DAS (Table 1) with M5 (7.5 t ha^-1 poultry manure; 94.61 cm) which was not significantly different from M₃ (15 t ha^-1 FYM; 93.98 cm). M₅  resulted in 19.57% higher plant height than the control (79.13 cm). M₄ (5 t ha^-1 poultry manure) and M₂ (10 t ha^-1 FYM) recorded 89.07 and 88.28 cm, respectively. Better plant growth with organic manure application may be due to improved nutrient availability and better soil conditions, which support plant growth. Katyar et al., (2024), Kavinder et al., (2019) and Bindia et al., (2019) reported similar findings. Among nitrogen treatments, N₁ (100% RDN) recorded the highest plant height (90.38 cm), followed by N₃ (75% RDN + one nano-urea spray; 88.93 cm) and N₂  (50% RDN + two nano-urea sprays; 87.74 cm). The plant height in N₃ and N₂ was 1.60 and 2.92% lower than that in N₁. The increased plant height at 100% RDN suggests that sufficient nitrogen facilitated better vegetative growth. Ojha et al., (2023) and Singh et al., (2023) reported similar results.


 
Dry matter accumulation (g m^-1 row length)
 
M₅ (7.5 t ha^-1 poultry manure) had the highest dry matter accumulation (74.50 g m^-1 row length), followed by M₃ (15 t ha^-1 FYM; 74.04 g m^-1 row length) and the two were statistically at par at 60 DAS (Table 1). The control had 57.79 g m^-1 row length, 28.91% less than M₅. The intermediate values were recorded for M₄ (5 t ha^-1 poultry manure; 68.30 g m^-1 row length) and M₂ (10 t ha^-1 FYM; 67.55 g m^-1 row length) which were significantly higher than the control. The higher dry matter accumulation with organic manure application may be due to better nutrient availability and improved soil conditions, which promoted plant growth. Similar findings were reported by Khan et al., (2023), Sharma et al., (2024) and Yadav et al., (2026). N₁ (100% RDN) had the highest dry matter accumulation (70.86 g m^-1 row length) followed by N₃ (68.37 g m^-1 row length) and N₂ (66.07 g m^-1 row length) which were 3.51 and 6.76% lower than N₁, respectively. The higher dry matter under N₁ may be attributed to the sufficient availability of nitrogen which favoured vegetative growth and biomass production. Zalavadiya et al., (2024) and Singh et al., (2023) reported similar results.
 
Leaf area index
 
At 60 DAS (Table 1), M₅  (7.5 t ha^-1 poultry manure) recorded the highest LAI (2.52), followed by M₃ (15 t ha^-1 FYM; 2.46). The LAI of the control was 1.88, 34.04% lower than that of M₅. The intermediate values were recorded by M₄ (5 t ha^-1 poultry manure; 2.31) and M₂ (10 t ha^-1 FYM; 2.23), which were significantly higher than that of the control. The higher LAI with organic manure application may be due to better nutrient availability, which promoted leaf growth and canopy development. These results are in line with those of Katyar et al., (2024) and Kumar et al., (2020). Among nitrogen treatments, N₁ (100% RDN) recorded the highest LAI (2.39), followed by N₃ (75% RDN + one nano-urea spray; 2.28) and N₂ (50% RDN + two nano-urea sprays; 2.16), which were 4.60 and 9.62% lower than N₁, respectively. This increased LAI under N₁ could be attributed to the sufficient nitrogen supply that promoted the development of leaves and canopy. Kumar et al., (2024) and Singh et al., (2023) reported similar results.
 
Yield parameters
 
Grain yield (q ha^-1)
 
Grain yield was significantly influenced by different organic manure treatments, as shown in Fig 1, which varied from 41.52 q ha^-1 in M₁ (control) to 55.67 q ha^-1 in M₅ (7.5 t ha^-1 poultry manure). M₅ resulted in 34.08% higher grain yield than the control and was not significantly different from M₃  (15 t ha^-1 FYM; 55.09 q ha^-1). The intermediate yields were recorded by M₄ (5 t ha^-1 poultry manure; 48.77 q ha^-1) and M₂ (10 t ha^-1 FYM; 48.20 q ha^-1), which were significantly higher than the control. This higher grain yield with organic manure application could be attributed to better nutrient availability and better crop growth that helped in better yield formation. Kavinder et al., (2019), Katyar et al., (2024), Sharma et al., (2024) and Khatua et al., (2025) reported similar results. Among nitrogen treatments, N₁ (100% RDN) recorded the highest grain yield (51.59 q ha_-1), followed by N₃ (75% RDN + one nano-urea spray; 49.98 q ha^-1) and N₂ (50% RDN + two nano-urea sprays; 47.98 q ha^-1), which were 3.12 and 7.00% lower than N₁, respectively. The increased grain yield under N₁ might be attributed to sufficient nitrogen supply during the crop growth period, leading to improved growth and yield development. Similar results were reported by Mushtaq (2023), Rani et al., (2024) and Maravi et al., (2025).


 
Straw yield (q ha^-1)
 
The organic manure treatments significantly influenced straw yield (Fig 1) which varied between 60.31 q ha^-1 (M₁-control) and 73.65 q ha^-1 (M5-7.5 t ha^-1 poultry manure). M₅  produced 22.12% more straw than the control and was not significantly different from M₃ (15 t ha^-1 FYM; 73.27 q ha^-1). The straw yield of M₄  (5 t ha^-1 poultry manure; 67.22 q ha^-1) and M₂ (10 t ha^-1 FYM; 66.88 q ha^-1) were also significantly higher than the control. The increased straw yield in the organic manure application may be attributed to the increased nutrient availability and plant growth, leading to increased biomass production. Sharma et al., (2024) and Katyar et al., (2024) reported similar results. Among nitrogen treatments, N₁ (100% RDN) recorded the highest straw yield (69.83 q ha^-1), followed by N₃ (75% RDN + one nano-urea spray; 68.47 q ha^-1) and N₂ (50% RDN + two nano-urea sprays; 66.50 q ha^-1). The straw yield of N₃ and N₂ was 1.95% and 4.77% lower than N₁, respectively. The increased straw production under N₁ might be attributed to sufficient nitrogen supply that facilitated vegetative growth and biomass production. Similar results were reported by Singh et al., (2024) and Ojha et al., (2023).
 
Biological yield (q ha^-1)
 
The biological yield (Fig 1) ranged from 101.61 q ha^-1 in M₁ (control) to 129.32 q ha^-1 in M₅ (7.5 t ha^-1 poultry manure) and was significantly affected by the organic manure treatments. M₅ had 27.27% more biological yield than the control and was not significantly different from M₃ (15 t ha^-1 FYM; 128.36 q ha^-1). The intermediate biological yields were recorded with M₄ (5 t ha^-1 poultry manure; 115.99 q ha^-1) and M₂ (10 t ha^-1 FYM; 115.01 q ha^-1). Among nitrogen treatments, N₁ (100% RDN) recorded the highest biological yield (121.42 q ha^-1), followed by N₃ (75% RDN + one nano-urea spray; 118.43 q ha^-1) and N₂ (50% RDN + two nano-urea sprays; 114.33 q ha^-1). The increased biological yield under N₁ could be explained by the availability of sufficient amounts of nitrogen, which favored vegetative growth and biomass production. Sharma et al., (2024) and Katyar et al., (2024) reported similar results. Among nitrogen treatments, N₁ (100% RDN) recorded the highest straw yield (69.83 q ha^-1), followed by N₃ (75% RDN + one nano-urea spray; 68.47 q ha^-1) and N₂  (50% RDN + two nano-urea sprays; 66.50 q ha^-1). The straw yield of N₃ and N₂ was 1.95% and 4.77% lower than N₁, respectively. The increased straw production under N₁ might be attributed to sufficient nitrogen supply that facilitated vegetative growth and biomass production. Similar results were reported by Singh et al., (2024) and Ojha et al., (2023).
 
Interaction effect of organic manures and nitrogen levels (M × N) on grain yield
 
The M × N interaction was significant for grain yield (Table 2). Reducing soil-applied nitrogen from N₁ (100% RDN) to N₂ (50% RDN + two nano-urea sprays) reduced grain yield under all organic manure treatments. The reduction was highest in the control (M₁), where grain yield decreased from 45.33 to 36.73 q ha^-1 (8.60 q ha^-1), while smaller reductions were observed in M₂  (1.82 q ha^-1), M₃  (3.02 q ha^-1), M₄ (1.75 q ha_-1) and M₅  (2.88 q ha^-1). The advantage of organic manure over the control was greater at the lower nitrogen level. For example, the difference between M₁  and M₂ increased from 3.79 q ha^-1 at N₁ to 10.57 q ha^-1 at N₂  and then decreased to 5.68 q ha^-1 at N₃. M₃ and M₅  remained statistically at par at all three nitrogen levels, with differences of 0.58, 0.72 and 0.43 q ha^-1  at N₁, N₂ and N₃, respectively, which were lower than the M × N CD (1.73 q ha^-1). This indicates that 15 t ha^-1 FYM and 7.5 t ha^-1 poultry manure produced similar grain yields under different nitrogen-management treatments. The better performance of organic manure at reduced nitrogen levels may be due to the additional nutrient supply and improved soil conditions provided by the manures, which helped maintain crop growth and yield. A similar interaction between organic manure and nitrogen management in wheat was reported by Bindia et al., (2019).


 
Interaction effect of organic manures and nitrogen levels (M × N) on straw yield
 
The same trend was observed for straw yield (Table 3). In the control (M₁), straw yield decreased from 64.34 q ha^-1 at N₁ to 55.32 q ha^-1 at N₂, a reduction of 9.02 q ha^-1. The reduction was smaller in M₂ (1.44 q ha^-1) and M₄ (1.46 q ha^-1) and was non-significant compared with the M × N CD (1.75 q ha^-1). The reduction was 2.59 q ha^-1 in M₃ and 2.14 q ha^-1 in M₅. Similar to grain yield, the benefit of organic manure over the control was higher at the lower N level. The difference between M₁ and M₂ increased from 3.21 q ha^-1 at N₁  to 10.79 q ha^-1 at N1 and then decreased to 5.69 q ha^-1 at N₃; all these differences were greater than the M × N CD (1.75 q ha^-1). There were no significant differences between M₃ and M₅ or between M₂ and M₄ at the various levels of nitrogen. The better performance of organic manure at reduced nitrogen levels may be due to the gradual release of nutrients from the manures, which helped maintain plant growth and straw production. This effect was more pronounced in the unmanured control, where the decrease in soil applied nitrogen resulted in a higher decrease in straw yield. Similar interactions between organic and inorganic nitrogen sources in wheat were reported by Reddycherla et al., (2026).


 
Interaction effect of organic manures and nitrogen levels (M × N) on biological yield
 
The interaction between M × N was also significant for biological yield (Table 4) and exhibited a similar trend to that of grain and straw yield. In the control (M₁), biological yield decreased from 109.67 q ha^-1 at N₁ to 91.38 q ha^-1 at N₂, a reduction of 18.29 q ha^-1. The reduction was much less in the manured treatments, varying from 3.21 q ha^-1 in M₄ to 5.62 q ha^-1 in M₃. The difference between M₁ and M₂  increased from 6.98 q ha^-1 at N₁ to 21.94 q ha^-1 at N₂, both of which were greater than the M × N CD (3.43 q ha^-1). This suggests that organic manure contributed to mitigating the impact of lower soil applied N on total biological yield. Organic manures provide a slow release of nutrients, which may have helped the crop to grow and produce biomass at lower nitrogen levels. Maravi et al., (2025) reported similar results for integrated nitrogen management in wheat.

Based on the two-year field experiment conducted under the agro-climatic conditions of Central Punjab, the application of 7.5 t ha^-1 poultry manure or 15 t ha^-1 FYM together with 100% RDN resulted in the highest growth and yield of wheat; 15 t ha^-1 FYM was statistically at par with 7.5 t ha^-1 poultry manure for most parameters. The reduced soil applied nitrogen with nano-urea foliar sprays (75% RDN + one spray or 50% RDN + two sprays) did not fully match the 100% RDN, suggesting that the foliar nano-urea supplementation did not fully replace the full recommended soil applied nitrogen under the conditions of this study. This recommendation should not be expanded to other agro-ecological regions without further multi-location studies.

The authors are thankful to the Department of Agronomy, School of Agriculture, Lovely Professional University, Phagwara, Punjab, for providing the research farm facilities and support required to conduct this study.

The authors declare no conflict of interest.