Effect of recommended dose of fertilizer levels and zinc application on growth, productivity, soil fertility and economics of greengram (Vigna radiata L.)

Introduction

Greengram (Vigna radiata L. Wilczek), popularly known as mungbean, is one of the most important pulse crops cultivated in tropical and subtropical regions of the world. The crop belongs to the family Fabaceae and occupies a significant position in Indian agriculture owing to its high nutritional value, short growth duration, adaptability to diverse agro-climatic conditions, and capacity to improve soil fertility through biological nitrogen fixation. India is recognized as both the primary centre of origin and the largest producer and consumer of greengram globally. The crop is widely grown during Kharif, summer, and spring seasons and serves as an important component of cereal-based and pulse-based cropping systems (Ali and Gupta, 2012) [2] .

Pulses play a crucial role in ensuring nutritional security for the rapidly increasing population of developing countries. Among pulses, greengram is highly valued because of its superior digestibility and rich nutritional composition. The grains contain approximately 20-25% protein, 60-65% carbohydrates, 3-4% minerals, and appreciable quantities of vitamins, particularly thiamine and riboflavin (Nair et al., 2019) [2] . The protein of greengram is rich in lysine, which complements cereal proteins and contributes significantly to balanced human nutrition (Ali and Gupta, 2012) [1] . Due to its easy digestibility and low flatulenceproducing nature, greengram is preferred over many other pulse crops and is consumed in the form of dal, sprouts, soups, sweets, and several traditional food products. India is the largest producer of pulses in the world; however, the productivity of many pulse crops remains below their genetic potential. According to recent agricultural statistics, greengram occupies about 5.5 million hectares with an annual production of approximately 3.1 million tonnes and average productivity of around 570 kg ha ¹, which is considerably lower⁻ than the achievable yield under improved management conditions (IIPR, 2024) [3] . The low productivity of greengram is primarily attributed to cultivation on marginal lands, inadequate fertilizer application, nutrient-deficient soils, moisture stress, and poor adoption of improved production technologies (Kumar et al., 2023) [4] . Apart from its nutritional significance, greengram contributes substantially to sustainable agriculture. Being a leguminous crop, it establishes a symbiotic association with Rhizobium bacteria and fixes atmospheric nitrogen into plant-available forms. This biological nitrogen fixation not only reduces the requirement of synthetic nitrogen fertilizers but also improves soil fertility for succeeding crops (Giller, 2001) [5] . Inclusion of greengram in crop rotations enhances soil organic matter, microbial activity, nutrient cycling, and overall soil health. Therefore, greengram plays a dual role in improving both food security and environmental sustainability. Despite these advantages, the productivity of greengram continues to be constrained by poor nutrient management. Modern intensive agriculture has accelerated nutrient mining from soils, resulting in widespread deficiencies of both macroand micronutrients. Continuous cultivation under cerealdominated systems has led to depletion of soil organic carbon and available nutrients, particularly nitrogen, phosphorus, and zinc (Brady and Weil, 2017) [6] . Consequently, balanced fertilization has emerged as one of the most important agronomic interventions for improving crop productivity and maintaining soil fertility. Recommended Dose of Fertilizers (RDF) provides a balanced supply of essential macronutrients required for optimum crop growth and development. Nitrogen is a major constituent of chlorophyll, amino acids, proteins, and nucleic acids, thereby promoting vigorous vegetative growth and photosynthetic activity (Mengel and Kirkby, 2001) [7] . Phosphorus plays a critical role in root development, nodulation, energy transfer, and reproductive growth, while potassium regulates enzyme activation, water relations, assimilate translocation, and stress tolerance (Vance et al., 2003) [8] . Deficiency of any of these nutrients adversely affects growth, flowering, pod development, and grain formation, ultimately reducing crop productivity. Among micronutrients, zinc has emerged as one of the most limiting factors affecting pulse production in India. Zinc deficiency is widespread in alkaline, calcareous, and intensively cultivated soils because of continuous nutrient removal and insufficient replenishment (Alloway, 2008) [9] . Recent soil fertility surveys have indicated that nearly half of the cultivated soils of India are deficient in available zinc, posing a serious challenge to sustainable crop production (Cakmak, 2008) [10] . Zinc plays an indispensable role in enzyme activation, auxin synthesis, chlorophyll formation, protein metabolism, membrane integrity, and reproductive development. Adequate zinc nutrition enhances root growth, photosynthetic efficiency, pollen viability, and seed formation, whereas deficiency results in chlorosis, stunted growth, poor nodulation, and reduced grain yield (Havlin et al., 2019) [11] . Several researchers have reported positive responses of greengram to zinc fertilization. Sharma et al. (2018) [12] observed significant improvement in plant height, nodulation, dry matter accumulation, and seed yield with zinc application. Similarly, Patel et al. (2020) [13] reported enhanced chlorophyll content, nutrient uptake, protein synthesis, and productivity of mungbean under balanced application of RDF and zinc. Kumar and Yadav (2022) [14] further demonstrated that combined application of higher RDF levels and zinc significantly improved fertilizer use efficiency and economic returns under alluvial soil conditions. The interaction between macronutrients and micronutrients is highly important for achieving sustainable crop production. Balanced supply of nitrogen, phosphorus, and potassium improves nutrient absorption and physiological efficiency, while zinc enhances metabolic activities and nutrient utilization within plants. This synergistic relationship promotes better growth, nodulation, dry matter production, flowering, pod development, and grain filling. Fageria et al. (2011) [15] emphasized that integrated management of macro-and micronutrients is essential for maximizing productivity while maintaining soil fertility and environmental quality. Recent studies have also highlighted the importance of balanced fertilization in improving nutrient use efficiency and soil health. Meena et al. (2021) [16] reported that integrated nutrient management significantly enhanced microbial activity, nutrient availability, and profitability of pulse-based cropping systems. In addition to increasing crop productivity, balanced fertilization contributes to sustainable soil management by improving nutrient cycling and reducing nutrient depletion. Considering the growing demand for pulses, declining soil fertility, and widespread zinc deficiency in Indian soils, optimization of fertilizer management practices has become imperative. The response of greengram to RDF and zinc application varies according to soil type, climatic conditions, and management practices. Therefore, location-specific studies are essential for identifying suitable fertilizer and zinc levels capable of maximizing growth, productivity, nutrient uptake, soil fertility, and profitability under prevailing agro-climatic conditions. Keeping these facts in view, the present investigation entitled "Effect of RDF Level and Zinc on Growth and Yield of Greengram (Vigna radiata L.)" was undertaken during the Kharif season under the agro-climatic conditions of Central Uttar Pradesh. The study was conducted to evaluate the influence of different RDF levels and zinc application rates on growth parameters, yield attributes, yield, soil fertility status, economics, and nutrient uptake of greengram and to identify the most suitable nutrient management strategy for enhancing productivity and profitability while sustaining soil health. The experimental data were subjected to statistical analysis using the analysis of variance (ANOVA) technique appropriate for Randomized Block Design as described by Gomez and Gomez (1984) [17] . Treatment means were compared using the Critical Difference (CD) test at the 5% level of significance. Correlation and regression analyses were also performed to study the relationship between yield and important growth and nutrient parameters. [18] , Patel et al. (2020) [13] , and Kumar and Yadav (2022) [14] , who observed significant improvement in vegetative growth under balanced nutrient management.

Materials and Methods

Results and Discussion

Growth Parameters of Greengram

The number of branches plant ¹ increased by ⁻ 102.40% over control due to improved nutrient availability and greater assimilate production. Zinc plays an important role in auxin synthesis and enzyme activation, resulting in enhanced branching and vegetative development (Alloway, 2008; Marschner, 2012) [9,19] .

Fig 1: Effect of Treatments on Growth

Nodulation response was also significantly enhanced by RDF and zinc application. Treatment receiving 125% RDF + Zinc @ 15 kg ha ¹ recorded ⁻ 99.35% higher nodules plant ¹⁻ than the control. Improved nodulation may be associated with better root growth, phosphorus availability, and enhanced Rhizobium activity. Similar observations were reported by Arunachalam et al. (2013) [20] and Rani et al. (2016) [21] . Dry matter accumulation followed a trend similar to plant height and nodulation. The highest dry matter accumulation (24.86 g plant ¹) was recorded under 125% RDF + Zinc @ 15 kg ha ¹,⁻ ⁻ representing a 74.09% increase over control. Higher biomass production under balanced fertilization resulted from improved photosynthetic efficiency, nutrient uptake, and carbohydrate synthesis. These results corroborate the findings of Fageria et al.

(2011) [15] , Sharma et al. (2018) [12] , and Meena et al. (2021) [16] .

Overall, the results clearly demonstrate that increasing RDF levels along with zinc application improved vegetative growth, nodulation behaviour, and biomass accumulation of greengram. The superiority of 125% RDF + Zinc @ 15 kg ha ¹ indicates the synergistic effect of macro-⁻ and micronutrients in enhancing physiological processes and nutrient use efficiency, ultimately leading to vigorous crop growth and higher productivity potential. [18] , Patel et al. (2020) [13] , and Kumar and Yadav (2022) [14] , who observed significant improvement in vegetative growth under balanced nutrient management.

Results and Discussion

Growth Parameters of Greengram

The number of branches plant ¹ increased by ⁻ 102.40% over control due to improved nutrient availability and greater assimilate production. Zinc plays an important role in auxin synthesis and enzyme activation, resulting in enhanced branching and vegetative development (Alloway, 2008; Marschner, 2012) [9,19] . Nodulation response was also significantly enhanced by RDF and zinc application. Treatment receiving 125% RDF + Zinc @ 15 kg ha ¹ recorded ⁻ 99.35% higher nodules plant ¹⁻ than the control.

Improved nodulation may be associated with better root growth, phosphorus availability, and enhanced Rhizobium activity. Similar observations were reported by Arunachalam et al. (2013) [20] and Rani et al. (2016) [21] . Dry matter accumulation followed a trend similar to plant height and nodulation. The highest dry matter accumulation (24.86 g plant ¹) was recorded under 125% RDF + Zinc @ 15 kg ha ¹,⁻ ⁻ representing a 74.09% increase over control. Higher biomass production under balanced fertilization resulted from improved photosynthetic efficiency, nutrient uptake, and carbohydrate synthesis. These results corroborate the findings of Fageria et al.

(2011) [15] , Sharma et al. (2018) [12] , and Meena et al. (2021) [16] . Overall, the results clearly demonstrate that increasing RDF levels along with zinc application improved vegetative growth, nodulation behaviour, and biomass accumulation of greengram. The superiority of 125% RDF + Zinc @ 15 kg ha ¹ indicates the synergistic effect of macro-⁻ and micronutrients in enhancing physiological processes and nutrient use efficiency, ultimately leading to vigorous crop growth and higher productivity potential. [12] , Patel et al. (2020) [13] , and Kumar and Yadav (2022) [14] .

Yield Attributes and Yield of Greengram

Seeds pod ¹ increased from 7.82 in the control to 11.26 under 125% RDF + Zinc @ 15 kg ha ¹,⁻ ⁻ representing a 43.99% increase. Improved nutrient supply enhanced photosynthetic activity and assimilate translocation towards developing reproductive organs, thereby increasing seed formation and retention. These findings agree with those reported by Balai et al.

(2017) [18] and Rani et al. (2016) [21] .

Test weight also improved significantly with balanced fertilization. The maximum test weight (41.86 g) recorded under 125% RDF + Zinc @ 15 kg ha ¹ was ⁻ 25.93% higher than the control. Zinc is known to play an important role in carbohydrate metabolism and grain filling, which contributed to better seed development and increased seed weight (Alloway, 2008) [9] . The highest seed yield (1.59 t ha ¹) was obtained under 125% RDF + Zinc @ 15 kg ha ¹, which was⁻ ⁻ 89.29% higher than the control (0.84 t ha ¹). The substantial increase in seed yield may be attributed⁻ to improved growth, enhanced nodulation, higher dry matter production, better nutrient uptake, and superior yield attributes. Balanced nutrient availability throughout the crop growth period ensured efficient conversion of photosynthates into economic yield. Similar results have been reported by Patel et al.

(2020) [13] , Meena et al. (2021) [16] , and Fageria et al. (2011) [15] . Stover yield followed a trend similar to seed yield. The maximum stover yield (32.84 q ha ¹) was⁻ recorded under 125% RDF + Zinc @ 15 kg ha ¹, representing a ⁻ 76.37% increase over control. Higher vegetative growth and biomass accumulation under balanced fertilization contributed directly to increased stover production Harvest index varied within a narrow range and remained statistically non-significant, indicating that nutrient management improved both grain and biomass production proportionately. The slight increase in harvest index under higher RDF and zinc treatments suggests improved partitioning of assimilates towards reproductive structures. Overall, the results clearly indicate that combined application of 125% RDF and Zinc @ 15 kg ha ¹⁻ significantly enhanced reproductive growth, grain development, and productivity of greengram. The synergistic effect of macronutrients and zinc improved physiological efficiency, nutrient utilization, and assimilate translocation, resulting in superior yield performance. [16] and Brady and Weil (2017) [6] .

Soil Fertility Status after Harvest

Available nitrogen status increased significantly with increasing RDF and zinc levels. Application of 125% RDF + Zinc @ 15 kg ha ¹⁻ recorded the highest available nitrogen (185.64 kg ha ¹), which represented an ⁻ 11.28% increase over the control. Enhanced biological nitrogen fixation, improved root activity, and greater nutrient cycling under balanced fertilization contributed to higher residual nitrogen availability. Similar observations were reported by Dakora and Keya (1997) [22] , Patel et al. (2020) [13] , and Kumar and Yadav (2022) [14] . Available phosphorus increased from 17.86 kg ha ¹ in the control to 24.16 kg ha ¹ under 125%⁻ ⁻ RDF + Zinc @ 15 kg ha ¹, representing a ⁻ 35.27% increase. Higher phosphorus availability may be attributed to adequate phosphorus application and improved nutrient solubilization in the rhizosphere. These findings are in agreement with those of Rani et al. (2016) [21] and Gupta et al. (2006) [23] . Available potassium also improved significantly with balanced nutrient management. The maximum potassium status (204.72 kg ha ¹) recorded under 125% RDF + Zinc @ 15 kg ha ¹⁻ ⁻ was 10.98% higher than the control. Increased root biomass and improved nutrient recycling contributed to better potassium availability after harvest. Available zinc status showed the most pronounced improvement. Application of 125% RDF + Zinc @ 15 kg ha ¹⁻ recorded the highest available zinc (0.94 mg kg ¹), which was ⁻ 67.86% higher than the control treatment. The direct addition of zinc sulphate and improved nutrient transformation processes were primarily responsible for the enhanced zinc status of soil. Similar results were reported by Alloway (2008) [9] , Ganeshamurthy et al. (2011) [24] , and Sharma et al. (2018) [12] . Soil pH and electrical conductivity remained statistically nonsignificant, indicating that RDF and zinc application did not adversely affect soil reaction or salinity status. This finding suggests that balanced fertilization can improve soil fertility without causing detrimental changes in soil chemical properties.

Overall, the results demonstrate that application of 125% RDF + Zinc @ 15 kg ha ¹⁻ not only maximized crop growth and yield but also improved residual soil fertility through enhanced nutrient availability and soil health. The findings support the concept of balanced nutrient management as a sustainable strategy for maintaining productivity and soil quality in pulsebased cropping systems. Although higher fertilizer and zinc doses slightly increased the cost of cultivation, the substantial increase in seed and stover yield resulted in markedly higher economic returns. Among all treatments, 125% RDF + Zinc @ 15 kg ha ¹⁻ recorded the highest gross return (146,254 ha ¹), net return (102,859 ha ¹), and benefit-cost ratio (3.37). The treatment₹ ⁻ ₹ ⁻ generated 89.29% higher net return compared with the control treatment, indicating the strong economic advantage of balanced nutrient management.

Economics of Greengram Cultivation

The higher gross return under this treatment was directly associated with superior seed yield, improved yield attributes, and greater biological productivity. Enhanced nutrient availability improved photosynthetic efficiency, nutrient uptake, and assimilate translocation, leading to greater marketable produce and increased farmer income. Similar findings have been reported by Patel et al. (2020) [13] , Sharma et al. (2018) [12] , and Kumar and Yadav (2022) [14] , who observed substantial improvement in profitability through balanced fertilization and zinc application.

The benefit-cost ratio increased from 2.16 under control to 3.37 under 125% RDF + Zinc @ 15 kg ha ¹, representing an improvement of ⁻ 56.02%. This clearly demonstrates that the additional investment in fertilizer and zinc application was economically justified due to the substantial increase in crop productivity and returns.

Treatments receiving 125% RDF consistently produced higher economic returns than corresponding 75% and 100% RDF treatments at each zinc level, highlighting the importance of adequate nutrient supply for maximizing profitability. Similarly, increasing zinc levels from 10 to 15 kg ha ¹ improved economic returns within each RDF category, emphasizing the role⁻ of zinc in enhancing crop performance under zinc-deficient soils.

The findings are supported by Meena et al. (2015) [25] , Kachhave et al. (2018) [26] , and Fageria et al. (2011) [15] , who concluded that balanced application of macro-and micronutrients significantly improves nutrient use efficiency, productivity, and profitability of pulse crops.

Overall, the economic analysis clearly establishes that application of 125% RDF along with Zinc @ 15 kg ha ¹⁻ is the most profitable nutrient management strategy for greengram cultivation under the agro-climatic conditions of Central Uttar Pradesh. Discussion of Correlation Analysis: Correlation analysis revealed a strong and positive association between seed yield and most of the growth, yield, and nutrient uptake parameters. Among all characters, pods plant ¹ (r =⁻ 0.982) exhibited the strongest positive relationship with seed yield, followed by dry matter accumulation (r = 0.973) and nitrogen uptake (r = 0.968).

Correlation and Regression Analysis

The highly significant positive correlation between seed yield and dry matter accumulation indicates that greater biomass production enhanced photosynthetic capacity and assimilate availability for reproductive growth. Similar observations have been reported by Fageria et al. (2011) [15] , Sharma et al. (2018) [12] , and Meena et al. (2021) [16] . Pods plant ¹ showed the highest association with seed yield because pod formation directly⁻ determines sink capacity and final grain production. Enhanced nutrient availability under higher RDF and zinc levels improved flowering, pod setting, and grain filling, thereby increasing yield potential. Nutrient uptake parameters also exhibited strong positive correlations with seed yield. Higher uptake of nitrogen, phosphorus, potassium, and zinc improved physiological efficiency, chlorophyll synthesis, protein formation, and assimilate translocation, ultimately enhancing productivity. These findings are in close agreement with Patel et al. (2020) [13] , Kumar and Yadav (2022) [14] , and Alloway (2008) [9] . Overall, the correlation analysis clearly demonstrated that growth parameters, yield attributes, and nutrient uptake collectively contributed towards increased seed yield of greengram under balanced nutrient management. The regression relationship between dry matter accumulation and seed yield (R² = 0.947) demonstrated that biomass production was one of the most important determinants of productivity. Increased dry matter accumulation reflected enhanced photosynthetic efficiency and nutrient utilization, resulting in greater assimilate availability for grain formation. [8,11] . The positive regression between zinc uptake and seed yield further highlights the critical role of zinc in reproductive development, enzyme activation, chlorophyll synthesis, and nutrient metabolism. Increased zinc uptake significantly improved crop productivity through enhanced physiological efficiency and nutrient use effectiveness.

Regression Analysis

These results indicate that improvement in growth characteristics, nutrient uptake, and reproductive parameters under higher RDF and zinc levels directly translated into higher seed yield and profitability.

Conclusion and Recommendations

The present investigation entitled "Effect of RDF Level and Zinc on Growth and Yield of Greengram (Vigna radiata L.)" clearly demonstrated that balanced nutrient management significantly influenced growth, yield attributes, yield, soil fertility status, nutrient uptake, and economics of greengram cultivation under the agro-climatic conditions of Central Uttar Pradesh. The experimental results revealed that increasing RDF levels along with zinc application enhanced vegetative growth, nodulation, dry matter accumulation, reproductive development, and ultimately crop productivity. Among the various nutrient management treatments, application of 125% RDF + Zinc @ 15 kg ha⁻¹ consistently produced superior performance with respect to plant height, branches plant⁻¹, nodules plant⁻¹, dry matter accumulation, pods plant⁻¹, seeds pod⁻¹, test weight, seed yield, and stover yield. The treatment recorded the highest seed yield (1.59 t ha⁻¹), representing nearly 89% improvement over the control treatment. Enhanced crop performance under this treatment was primarily attributed to adequate and balanced availability of macro-and micronutrients, resulting in improved photosynthetic activity, nutrient uptake, enzyme activation, assimilate translocation, and reproductive efficiency.

Post-harvest soil analysis indicated that balanced fertilization also improved residual soil fertility by increasing available nitrogen, phosphorus, potassium, and zinc status. The improvement in soil nutrient availability reflects the beneficial role of integrated macro-and micronutrient management in sustaining soil health and long-term productivity. Correlation and regression analyses further established strong positive relationships between seed yield and major growth, yield, and nutrient uptake parameters, confirming that improved nutrient availability directly contributed to enhanced crop productivity. Economic analysis revealed that 125% RDF + Zinc @ 15 kg ha⁻¹ generated the highest gross return (₹146,254 ha⁻¹), net return (₹102,859 ha⁻¹), and benefit-cost ratio (3.37), indicating that the additional investment in fertilizer and zinc application was economically rewarding. Therefore, balanced fertilization not only increased productivity but also enhanced profitability and resource-use efficiency.

Recommendation

Based on the findings of the present investigation, application of 125% Recommended Dose of Fertilizers (25:50:25 kg N:P₂O₅:K₂O ha⁻¹ equivalent) along with Zinc @ 15 kg ha⁻¹ through zinc sulphate is recommended for greengram cultivation under the sandy loam soils of Central Uttar Pradesh to achieve higher growth, productivity, nutrient uptake, soil fertility improvement, and maximum economic returns. This nutrient management practice may serve as an effective strategy for enhancing pulse production and sustaining soil health under intensive cropping systems.

References

1. Alloway BJ. Zinc in soils and crop nutrition. 2nd ed. Brussels: International Zinc Association and International Fertilizer Industry Association; 2008.
2. Ali M, Gupta S. Carrying capacity of Indian agriculture: Pulse crops. Current Science. 2012;102(6):874-881.
3. Arunachalam P, Kannan P, Prabukumar G, Govindaraj M. Zinc deficiency effects and management in pulse crops. African Journal of Agricultural Research. 2013;8(45):56385644. DOI:10.5897/AJAR2013.7058.
4. Balai RC, Verma HP, Sharma MP, Meena LR. Effect of phosphorus and zinc on growth and yield of mungbean (Vigna radiata L.). International Journal of Current Microbiology and Applied Sciences. 2017;6(8):1179-1185. DOI:10.20546/ijcmas.2017.608.145.
5. Bhowmick MK, Dhara MC, Duary B, Biswas PK, Bhattacharyya P. Improvement of mungbean productivity through micronutrient management. Legume Research. 2014;37(6):612-617. DOI:10.5958/0976-0571.2014.00658.7.
6. Brady NC, Weil RR. The nature and properties of soils. 15th ed. Boston: Pearson Education; 2017.
7. Cakmak I. Enrichment of cereal grains with zinc: Agronomic or genetic biofortification? Plant and Soil. 2008;302:1-17. DOI:10.1007/s11104-007-9466-3.
8. Dakora FD, Keya SO. Contribution of legume nitrogen fixation to sustainable agriculture in sub-Saharan Africa. Soil Biology and Biochemistry. 1997;29(5-6):809-817. DOI:10.1016/S0038-0717(96)00225-8.
9. Fageria NK, Baligar VC, Jones CA. Growth and mineral nutrition of field crops. 3rd ed. Boca Raton: CRC Press; 2011.
10. Food and Agriculture Organization of the United Nations. FAOSTAT: Food and Agriculture Organization Statistical Database. Rome: FAO; 2024.
11. Ganeshamurthy AN, Reddy KS, Singh G. Zinc nutrition in Indian agriculture. Indian Journal of Fertilisers. 2011;7(10):58-68.
12. Giller KE. Nitrogen fixation in tropical cropping systems. 2nd ed. Wallingford: CAB International; 2001. DOI:10.1079/9780851994178.0000.
13. Gomez KA, Gomez AA. Statistical procedures for agricultural research. 2nd ed. New York: John Wiley & Sons; 1984.
14. Gupta SC, Sharma AK, Singh RV. Effect of phosphorus and zinc on productivity and nutrient uptake of mungbean. Indian Journal of Agronomy. 2006;51(2):145-148.
15. Havlin JL, Tisdale SL, Nelson WL, Beaton JD. Soil fertility and fertilizers: An introduction to nutrient management. 9th ed. Boston: Pearson Education; 2019.
16. Hussain N, Khan MA, Ahmad R. Influence of micronutrients on growth and productivity of pulse crops. Pakistan Journal of Agricultural Sciences. 2012;49(4):497-503.
17. Indian Institute of Pulses Research. Vision 2050: Pulses for nutritional security. Kanpur: Indian Institute of Pulses Research; 2024.
18. Jat RS, Ahlawat IPS, Ghosh PK. Integrated nutrient management in pulse-based cropping systems. Indian Journal of Agronomy. 2012;57(3):247-254.
19. Kachhave KG, Bhalerao PD, Patil SR. Response of greengram to zinc fertilization under rainfed conditions. International Journal of Chemical Studies. 2018;6(4):11451149.
20. Khan HR, McDonald GK, Rengel Z. Zinc fertilization improves growth and nutrient uptake in legumes. Plant and Soil. 2004;258:267-277. DOI:10.1023/B:PLSO.0000016545.99012.0f.
21. Kumar R, Yadav SS. Effect of integrated nutrient management on growth, yield and nutrient uptake of greengram. Legume Research. 2022;45(4):476-482. DOI:10.18805/LR-4567.
22. Marschner P. Marschner's mineral nutrition of higher plants. 3rd ed. London: Academic Press; 2012. DOI:10.1016/C2009-0-63043-9.
23. Meena BL, Meena RS, Verma HP, Kumar S. Influence of integrated nutrient management on productivity and economics of greengram. Annals of Agricultural Research. 2015;36(4):401-406.
24. Meena RS, Kumar S, Yadav GS, Lal R. Integrated nutrient management for sustainable pulse production: A review. Agronomy. 2021;11(6):1104. DOI:10.3390/agronomy11061104.
25. Mengel K, Kirkby EA. Principles of plant nutrition. 5th ed. Dordrecht: Kluwer Academic Publishers; 2001.
26. Ministry of Agriculture and Farmers Welfare. Agricultural statistics at a glance. New Delhi: Government of India; 2024.
27. Nair RM, Schafleitner R, Kenyon L, Srinivasan R, Easdown W, Ebert AW, et al. Genetic improvement of mungbean. Plant Breeding Reviews. 2019;43:1-69. DOI:10.1002/9781119616801.ch1.
28. Patel KK, Singh AK, Verma RP. Effect of RDF and zinc levels on growth, yield and nutrient uptake of mungbean under alluvial soils. International Journal of Current Microbiology and Applied Sciences. 2020;9(7):2456-2467. DOI:10.20546/ijcmas.2020.907.288.
29. Prasad R, Shivay YS, Kumar D, Sharma SN. Learning by doing exercises in soil fertility. New Delhi: Division of Agronomy, Indian Agricultural Research Institute; 2006.
30. Rani P, Sharma SK, Yadav BL. Effect of phosphorus and zinc fertilization on growth and productivity of greengram. Legume Research. 2016;39(3):475-479. DOI:10.18805/lr.v39i3.10719.
31. Sharma A, Singh R, Kumar V, Yadav R. Zinc fertilization improves growth, yield and nutrient uptake of mungbean. Journal of Pharmacognosy and Phytochemistry. 2018;7(6):1642-1647.
32. Singh P, Pal RK, Kumar M, Kumar S. Evaluation of integrated nutrient management practices for enhancing productivity and profitability of chickpea (Cicer arietinum L.). IJERT. 2026;15(5).
33. Vance CP, Uhde-Stone C, Allan DL. Phosphorus acquisition and use in legumes. Plant and Soil. 2003;248:193-218. DOI:10.1023/A:1023077110211.
34. Walkley A, Black IA. An examination of the Degtjareff method for determining soil organic matter and a proposed modification of the chromic acid titration method. Soil Science. 1934;37(1):29-38. DOI:10.1097/00010694-193401000-00003.
35. Olsen SR, Cole CV, Watanabe FS, Dean LA. Estimation of available phosphorus in soils by extraction with sodium bicarbonate. Washington (DC): United States Department of Agriculture; 1954. USDA Circular No. 939.
36. Jackson ML. Soil chemical analysis. New Delhi: Prentice Hall of India; 1973.
37. Subbiah BV, Asija GL. A rapid procedure for estimation of available nitrogen in soils. Current Science. 1956;25:259260.
38. Lindsay WL, Norvell WA. Development of DTPA soil test for zinc, iron, manganese and copper. Soil Science Society of America Journal. 1978;42(3):421-428. DOI:10.2136/sssaj1978.03615995004200030009x.
39. Bouyoucos GJ. Hydrometer method improved for making particle size analysis of soils. Agronomy Journal. 1962;54(5):464-465. DOI:10.2134/agronj1962.00021962005400050028x.
40. Black CA. Methods of soil analysis. Madison (WI): American Society of Agronomy; 1965.
41. Piper CS. Soil and plant analysis. Adelaide: Hans Publishers; 1966.
42. Yoshida S. Fundamentals of rice crop science. Los Baños: International Rice Research Institute; 1981.
43. Singh U, Ladha JK, Castillo EG, Punzalan G, Tirol-Padre A, Duqueza M. Genotypic variation in nitrogen use efficiency in medium-and long-duration rice. Plant and Soil. 1998;194:171-180.
44. Lal R. Soil health and carbon management. Soil Systems. 2020;4(3):36. DOI:10.3390/soilsystems4030036.