Optimizing nitrogen management with foliar spray for enhanced productivity and profitability of summer mungbean (Vigna radiata L.)

Introduction

Mungbean (Vigna radiata L.) is an important pulse crop in India, contributing significantly to the dietary protein of the population. In Gujarat, it is grown extensively, but productivity remains low due to nutrient stress and imbalanced fertilization. Nano urea, developed by IFFCO, is a liquid fertilizer containing 4% nitrogen in nanoscale form, which enhances nutrient use efficiency up to 80% compared to 30-50% in conventional urea. Foliar application of nano urea at critical stages may reduce dependence on soil-applied urea, improving sustainability and soil health. Mungbean (Vigna radiata L. Wilczek), popularly referred to as moong, mung, or green gram, is an important pulse crop belonging to the family Fabaceae. Owing to its good digestibility, it is widely regarded as a relatively light and easily digestible pulse. Besides its use as a food legume, mungbean has diverse applications in crop and livestock production. Its immature green pods are consumed as a vegetable, whereas the haulm serves as a valuable source of feed for livestock. The crop is also grown as a cover and soil-conserving crop, and its rapidly decomposing biomass makes it suitable for incorporation into the soil as green manure. Mungbean seeds possess considerable nutritional value, with reported protein and moisture contents ranging from 22.5-27.94% and 5.26-9.95%, respectively. The concentrations of fat, crude fibre, ash, and carbohydrates have been reported to vary from 0.12-2.31%, 2.90-17.04%, 2.91-4.26%, and 32.14-66.33%, respectively. Furthermore, mungbean provides a range of nutritionally important mineral elements, including calcium, magnesium, phosphorus, potassium, and sodium among the major minerals, along with manganese, iron, copper, and zinc as trace elements. (Sudhakaran and Bukkan, 2021) [15] . The advancement of crop productivity and nutritional quality is closely associated with adequate nutrient management, particularly following the development of high-yielding cultivars with greater responsiveness to fertilizer application. Among the essential nutrients required by plants, nitrogen (N) has a prominent role in determining crop growth and productivity. Adequate nitrogen availability encourages vigorous vegetative development and contributes to the synthesis of several vital cellular components, including amino acids and proteins, enzymes, and chlorophyll pigments. However, significant amounts of nitrogen are lost to the atmosphere through volatilization, denitrification, leaching and runoff. Despite these concerns, studies show that crops utilize just 45-50% of applied nitrogen in current high-input, profit-oriented agricultural systems.

Materials and Methods

The experiment was conducted at College Farm, N. M. College of Agriculture, Navsari Agricultural University, Navsari (20°57′N, 72°54′E, 10 m AMSL) during summer 2024. The soil was clayey, low in nitrogen (235.72 kg ha⁻¹), medium in organic carbon (0.56%) and available P 2 O 5 (45.32 kg ha⁻¹), high in available K 2 O (581.92 kg ha⁻¹) with a pH of 7.32. The experiment was laid out in a Randomized Block Design with eight treatments and three replications. The treatments were:

100% RDF (20:40:00 NPK kg ha⁻¹) T3 80% RDF + Spray of nano urea @ 4.0 ml/litre at 30 DAS T4 80% RDF + Spray of nano urea @ 4.0 ml/litre at 45 DAS T5 80% RDF + Spray of urea @ 2% at 30 DAS T6 80% RDF + Spray of urea @ 2% at 45 DAS T7 60% RDF + Spray of nano urea @ 4.0 ml/litre at 30 DAS + 45 DAS T8 60% RDF + Spray of urea @ 2% at 30 DAS + 45 DAS Observations were recorded on growth, yield attributes, yield, protein content and economics of summer mungbean.

Gross plot size 3.60 m x 4.00 m Net plot size 2.70 m x 3.60 m Spacing 45 cm x 10 cm Recommended dose of fertilizers (kg ha -1 ) 20:40:00 NPK Nitrogen (N) and phosphorus (P₂O₅) were supplied through urea and diammonium phosphate (DAP), respectively. The recommended quantities of both fertilizers were applied as a basal dose at the time of sowing of green gram. IFFCO Nano Urea was employed as the source of nano-nitrogen. Foliar application of Nano Urea was carried out at 30 and 45 days after sowing (DAS) according to the respective treatment schedules.

Results and Discussion

Growth parameter

Treatment T 2 (100% RDF) recorded significantly higher growth parameters in mungbean, including plant height (48.53 cm), dry matter production plant⁻¹ (24.89 g) and number of branches plant - 1 (7.80) in Table 1. However, it was statistically at par with treatments T 5 (80% RDF + spray of urea @ 2% at 30 DAS) and T 6 (80% RDF + spray of urea @ 2% at 45 DAS), while treatment T 3 (80% RDF + spray of nano urea @ 4.0 ml/litre at 30 DAS), T 4 (80% RDF + spray of nano urea @ 4.0 ml/litre at 45 DAS) and T 8 (60% RDF + spray of urea @ 2% at 30 DAS + 45 DAS) also remained at par in case of number of branches plant [10] , Sharma et al. (2022) [12] , Kaushik et al. (2023) [5] , Subramani et al. (2023) [14] , Kumar et al. (2023) [6] , Singh et al. (2023) [13] , Pal et al. (2023) [7] and Rani et al. (2024) [9] .

Yield Attributes and Yield Performance

Significant differences were observed among treatments with respect to yield-attributing characters and yield of mungbean. The maximum number of pods plant⁻¹ (32.00) was recorded under 100% RDF (T 2 ), which could be attributed to the balanced and adequate supply of essential nutrients that enhanced vegetative growth, flowering and pod setting. This was statistically at par with T 6 (28.93), while the lowest number of pods plant⁻¹ (18.33) was observed in the absolute control (T 1 ). Similarly, significantly higher pod length (9.14 cm) was obtained with T 2 but remaining at par with treatments T 6 (8.79 cm), T 5 (8.73 cm), and T 3 (8.48 cm), whereas the lowest value (6.85 cm) was recorded under T 1 .

Number of seeds pod⁻¹ was significantly higher under treatment T 2 (12.27) and remained at par with treatments T 6 and T 5 . These results are in close agreement with the findings of Singh and Singh (2014) [13] , Saitheja et al. (2022) [11] , Chandar et al. (2023) [1] and Nandhakumar et al. (2025) [6] . With respect to yield, treatment T 2 (100% RDF) recorded the significantly higher seed yield (1420 kg ha⁻¹) and haulm yield (2627 kg ha⁻¹). Seed yield under treatment T 2 was at par with T 5 , while haulm yield was statistically comparable with treatments T 3 , T 4 , T 5 and T 6 . Higher haulm yield under these treatments was directly associated with improved growth attributes such as plant height, number of branches and dry matter accumulation, supported by continuous nutrient supply through basal application and foliar sprays, which also enhanced nutrient uptake during the crop growth period. The harvest index was also significantly higher under T 2 (35.12%), which remained at par with all treatments except T 1 , where the lowest harvest index of 28.46% was recorded. These findings corroborate the results of Saitheja et al. (2022) [11] , Chandar et al.

(2023) [1] , Hossain et al. (2023) [3] and Chavan et al. (2024) [2] .

Quality parameter

Significant variation in protein content and protein yield of mungbean was observed due to different treatments. Significantly higher protein content (23.56%) was recorded with treatment T 2 (100% RDF) which was at par with treatments T 5 (80% RDF + spray of urea @ 2% at 30 DAS), T 6 (80% RDF + spray of urea @ 2% at 45 DAS), T 3 (80% RDF + spray of nano urea @ 4.0 ml/litre at 30 DAS), T 4 (80% RDF + spray of nano urea @ 4.0 ml/litre at 45 DAS) and T 7 (60% RDF + spray of nano urea @ 4.0 ml/litre at 30 DAS + 45 DAS). Similarly, significantly higher protein yield (334.20 kg ha⁻¹) was also recorded under treatment T 2 (100% RDF) but it remained statistically at par with T 5 (80% RDF + spray of urea @ 2% at 30 DAS). The increase in protein yield under T 2 was mainly due to the combined effect of higher seed yield and enhanced protein content. The improvement in protein traits can be directly attributed to higher nitrogen availability, as nitrogen is a vital constituent of amino acids, the building blocks of protein. Adequate nitrogen supply thus enhanced nitrogen accumulation in seeds, resulting in higher protein content and yield. In contrast, the lowest protein content (18.90%) and protein yield (139.95 kg ha⁻¹) were recorded under absolute control (T 1 ). These findings are in close agreement with the reports of Tomar et al. (2022) [17] and Islam et al. (2023) [4] .

Economics

Treatment T 7 (60% RDF + foliar spray of nano urea @ 4.0 ml/litre at 30 and 45 DAS) incurred the highest cost of cultivation (47,096 ₹ ha -1 ). However, the maximum gross return (1,20,398 ₹ ha -1 ), net return (76,123 ₹ ha -1 ) and benefit-cost (B:C) ratio (1.72) were observed under treatment T 2 (100% RDF). In contrast, the control treatment (T 1 ) recorded the lowest economic returns, with gross return of 66,804 ₹ ha -1 , net return of 25,967 ₹ ha -1 and B:C ratio of 0.64. The higher income might be due to higher yield and lower cost of cultivation under this treatment. The results were similar to the findings of Patel et al. (2021) [8] and Tejaswini et al. (2022) [16] .

Conclusion

Application of 100% RDF (20:40:00 NPK kg ha⁻¹) proved most effective for growth, yield, nutrient uptake and profitability of summer mungbean under south Gujarat condition. However, 80% RDF with foliar spray of nano urea at flowering or pod formation stage can serve as a fertilizer-saving alternative without significant yield reduction.

References

1. Chandar AD, Manuel RI, Joseph PA, Kumar KU, Kumar PD. Effect of integrated nutrient management in black gram for its yield and quality in Coimbatore, Tamil Nadu, India. International Journal of Environment and Climate Change. 2023;13(11):3877-3887.
2. Chavan YS, Bodake PS, Thorat TN, Kasture MC, Dalvi SG, Rajemahadik VA, et al. Nutrient management in green gram (Vigna radiata L. Wilczek) and its effect on growth and yield. International Journal of Advanced Biochemistry Research. 2024;8(8):437-441.
3. Hossain ME, Begum S, Hoque MM, Islam MM, Shahed M. Foliar application of nano urea on growth and yield of binamash-3 (Vigna mungo L.). Journal of Agroforestry and Environment. 2023;16(2):131-133.
4. Islam MZA, Alim SMA, Hoque MM, Islam MM, Adhikary S. Effect of nano urea foliar spray on yield and yield attributes of black gram (Vigna mungo L.). Journal of Agroforestry and Environment. 2023;16(1):64-66.
5. Kaushik T, Singh R. Effect of nano urea and recommended dose of fertilizers on growth, yield and economics of rice (Oryza sativa L.). International Journal of Agriculture Sciences. 2023;15(8):127-132.
6. Kumar R, Sharmili K, Balaganesh B, Manuel RI. Comparative evaluation of neem-coated urea and nano urea on the growth and physiological attributes of finger millet (Eleusine coracana L. Gaertn). International Journal of Environment and Climate Change. 2023;13(8):785-792.
7. Pal RK, Maurya DK, Kumar S, Singh R. Assessing the influence of nano urea on the growth and yield of irrigated wheat (Triticum aestivum L.) crop. International Journal of Environment and Climate Change. 2023;13(12):843-851.
8. Patel RH, Patel MR. Response of different nitrogen levels and foliar spray of urea on yield and economics of wheat (Triticum aestivum L.). An Asian Journal of Soil Science. 2021;16(1):45-49.
9. Rani G, Prakash H, Kumari G, Choudhary SK, Seema, Pathak SK. Effect of nano urea on growth, yield and nitrogen use efficiency of irrigated wheat (Triticum aestivum L.). Journal of Advances in Biology & Biotechnology. 2024;27(9):43-52.
10. Rawate D, Patel JR, Agrawal AP, Agrawal HP, Pandey D, Patel CR, et al. Effect of nano urea on productivity of wheat (Triticum aestivum L.) under irrigated condition. The Pharma Innovation Journal. 2022;11(9):1279-1282.
11. Saitheja V, Senthivelu M, Prabukumar G, Prasad V. Maximizing the productivity and profitability of summer irrigated greengram (Vigna radiata L.) by combining basal nitrogen dose and foliar nutrition of nano and normal urea. International Journal of Plant and Soil Science. 2022;34(22):109-116.
12. Sharma SK, Sharma PK, Mandeewal RL, Sharma V, Chaudhary R, Pandey R, et al. Effect of foliar application of nano-urea under different nitrogen levels on growth and nutrient content of pearl millet (Pennisetum glaucum L.). International Journal of Plant and Soil Science. 2022;34(20):149-155.
13. Singh YK, Bal Veer Singh, Katiyar D, Saikanth DRK, Kaushal Kumar, Omkar Singh, et al. Efficacy of nano fertilizers on yield, yield attributes and economics of wheat. International Journal of Environment and Climate Change. 2023;13(7):291-297.
14. Subramani T, Velmurugan A, Bommayasamy N, Kumar M, Ramakrishna Y, Swarnam TP. Effect of nano urea (liquid) on yield and fertilizer saving in rice under island ecosystem. Ecology Environment and Conservation. 2023;29:377-383.
15. Sudhakaran SM, Bukkan DS. A review on nutritional composition, antinutritional components and health benefits of green gram (Vigna radiata (L.) Wilczek). Journal of Food Biochemistry. 2021;45(6):1-19.
16. Tejaswini S, Kumar S, Singh R. Evaluation of green gram (Vigna radiata L. var PDM 139) cultivated under different levels of nano urea and organic/inorganic fertilizers. Asian Journal of Soil Science and Plant Nutrition. 2022;14(2):118123.
17. Tomar M, Choudhary J, Jain D, Patidar R, Choudhary R. Effect of nano urea vs conventional urea on the nutrient content, uptake and economics of black wheat (Triticum aestivum L.) along with biofertilizers. Biological Forum -An International Journal. 2022;14(2):499-504.