Effect of foliar application of boron, zinc and manganese on vegetative growth of Potato (Solanum tuberosum L. c.v Kufri lima)

Introduction

The potato (Solanum tuberosum L.) constitutes a fundamental pillar of global food security, positioned as the third most significant food crop globally, following rice and wheat. Cultivated in over 150 nations across various agro-ecological contexts, this crop demonstrates an exceptional ability to yield high caloric output per unit area and enhance water use efficiency in comparison to predominant cereal crops. Originating from the vicinity of Lake Titicaca in the elevated Andes region around 6000 BC, this Solanaceous species flourishes optimally within a thermal range of 18-20 °C. Its comprehensive nutritional composition, abundant in essential carbohydrates, potassium, ascorbic acid, dietary fibre, bioavailable iron, and crucial B-complex vitamins, renders it vital for combating malnutrition and economic susceptibility in developing areas of South Asia, South America, and Africa. Within the Indian agricultural framework, the Indo-Gangetic alluvial plains of Uttar Pradesh are recognized as a principal region for potato cultivation, accounting for approximately 35% of the national output. Nevertheless, the sustainability and productivity of intensive cropping systems, such as the widely implemented maize-potato-mung bean rotation, are increasingly undermined by the multi-nutrient depletion within the soil profile. While the management of macronutrients (Nitrogen, Phosphorus, Potassium) has garnered considerable focus, the concurrent depletion of essential trace elements or micronutrients continues to pose a significant limitation. Micronutrients, although required in minuscule amounts, serve as catalytic agents in regulating primary plant metabolic processes, facilitating structural cell wall formation, activating enzyme cascades, directing electron transport pathways, and fortifying defences against abiotic stress. Notably, Zinc (Zn), Boron (B), and Manganese (Mn) exhibit pronounced and pervasive deficiencies in the alluvial soils of northern India, constraining the structural development and canopy expression of cultivars such as cv. Kufri Lima. Foliar feeding has surfaced as a methodologically effective and expeditious diagnostic strategy to rectify these deficiencies. In contrast to conventional soil amendments, which are often subjected to significant nutrient immobilization, precipitation, or leaching under alkaline soil conditions (characterized by high pH and calcium carbonate accumulation), foliar sprays facilitate the direct application of dissolved nutrients onto the active canopy. The essential nutrients penetrate through the leaf cuticle and stomatal apertures, entering the metabolic sinks with immediacy. This focused approach guarantees swift biochemical assimilation, thereby optimizing vegetative parameters during critical structural phases such as the initial stolon formation and the development of vegetative branches.

Physiological Functionality of Zinc (Zn)

Zinc functions as an essential catalytic and structural element in more than 300 plant enzymes and signaling proteins. It serves as a principal regulator of tryptophan biosynthesis, which is the crucial amino acid precursor for Indole-Acetic Acid (IAA), the predominant auxin that facilitates cellular elongation, apical dominance, and the elongation of structural nodes. Furthermore, zinc is indispensable for the assembly of proteins, the replication of RNA and DNA, the stability of chlorophyll, and the process of carbon fixation mediated by carbonic anhydrase. In instances of severe zinc deficiency, potato plants demonstrate typical morphological aberrations such as pronounced internodal compression, resetting, significant leaf chlorosis, and structural stunting, which constrains overall light interception.

Structural Functionality of Boron (B)

Boron serves primarily as a pivotal structural element within the cell wall matrix, facilitating the cross-linking of pectic polysaccharides (notably rhamnogalacturonan II) to confer mechanical stability and modulate elasticity during phases of active growth. It is indispensable for maintaining the structural integrity of plasma membranes, facilitating cellular division within apical meristems, and enabling the phloem-mediated translocation of sucrose from foliar sources to vegetative sinks. Given that boron exhibits minimal phloem mobility in the majority of higher plants, any disruption in its external supply precipitates rapid functional failure in apical growing points, culminating in apical necrosis, a loss of apical dominance, and a compromise in the mechanical robustness of petiole and stem structures.

Catalytic Functionality of Manganese (Mn)

Manganese functions as a vital element within the oxygenevolving complex (OEC) of Photosystem II, facilitating the photolytic dissociation of water molecules that supply electrons essential for the photosynthetic electron transport chain. It serves as an obligatory activator for critical metabolic enzymes, encompassing those regulating nitrogen assimilation (nitrate reductase), fatty acid biosynthesis, and the phenylpropanoid pathway, which is integral to the biosynthesis of lignin and structural flavonoids. A deficiency in manganese elicits 'speckled yellows' chlorosis, interveinal structural deterioration, and the emergence of localized necrotic lesions, leading to a reduction in total leaf area and a consequent impairment in photosynthetic efficiency.

Materials and Methods Experimental Sites and Location

The field experiment was executed during the Rabi season of 2025-2026 at Plot Number 13 of the Research Field located at the Centre of Excellence for Vegetable Science, Chandra Shekhar Azad University of Agriculture & Technology, Kanpur, India (26.46° N, 80.33° E). The site is characterized by a typical subhumid, subtropical climate, featuring hot, arid summers and cool winters. Weekly meteorological observations throughout the active crop cycle recorded mean maximum temperatures varying from 15.2 °C to 32.4 °C, while minimum temperatures oscillated between 2.0 °C and 10.5 °C. The relative humidity at 07:00 AM consistently remained elevated at levels between 95% and 97%, whereas the afternoon relative humidity (at 02:00 PM) fluctuated between 30% and 64%. The historical cropping sequence over the previous three seasons adhered to a consistent maize-potato-mung bean rotation, thereby ensuring uniform baseline management of structural conditions across the experimental plot area.

Experimental Architecture and Treatments Setup

The experimental design was structured as a Randomized Block Design (RBD) comprising eight distinct treatments, each replicated three times across 24 plots measuring 3.0 m × 2.4 m. The certified potato cultivar 'Kufri Lima' was sown on November 19, 2025, employing a uniform spacing of 60 cm between rows and 20 cm between individual plants. Healthy and uniform seed tubers (ranging from 35-40 mm in diameter and weighing 45-50 g) were subjected to treatment with a 0.2% Mancozeb solution for a duration of 10 minutes to mitigate the risk of soil-borne pathogens prior to planting. The experimental plots received a uniform basal fertilizer application of N:P: K at 150:90:100 kg ha⁻¹. Nitrogen was managed as a split application, with half applied basally and the remaining half top-dressed during the first earthing-up operation at 45 days after planting.

Execution of Foliar Spray Schedules

The foliar interventions were meticulously administered at 30, 50, and 70 days post-planting (DAP) utilizing a calibrated handoperated sprayer fitted with a high-efficiency spray lance. This configuration guaranteed consistent canopy coverage while mitigating the potential for draft drift affecting neighboring experimental plots. To avert leaf scorching and optimize stomatal absorption, applications were conducted exclusively during the early morning hours (07:30 AM to 09:30 AM) when wind velocities were minimal and relative humidity levels were deemed optimal. Stock solutions were freshly formulated by dissolving pure analytical-grade mineral salts directly in deionized water, employing suitable personal protective equipment to uphold experimental safety and precision standards.

Results and Discussion

The statistical examination of the vegetative growth parameters indicated that foliar micronutrient applications profoundly altered the structural architecture of potato cultivar Kufri Lima throughout active growth phases. The specific vegetative observations are elucidated below.

Table 1 and Figure 1 present empirical data elucidating the Effect of Foliar Application of Boron, Zinc and Manganese on plant height at 30 days after planting (DAP), it was observed that the application of T₈: (Boron 2.0 g + Zinc 1.0 g + Manganese 2.0 g) at (27.17 cm). In contrast, T 1 Control exhibited the lowest plant height (23.43 cm). The analysis of variance substantiated that treatment discrepancies were statistically non-significant (NS) at this nascent stage, signifying a lag phase in nutrient absorption and structural assimilation. Upon reaching at (60 DAP), plant height measurements varied from (56.23 cm) and in the control (T₁) to (41.93 cm) At the terminal vegetative maturity stage (90 DAP), the tri-elemental combination T₈ achieved the maximum plant height of (70.63 cm). The control plot (T₁) recorded the minimal plant height of 43.93 cm at 90 DAP. The enhanced plant height observed under T₈ (Boron 2.0 g + Zinc 1.0 g + Manganese 2.0 g) at 60 and 90 DAP indicates the synergistic effect of micronutrients in promoting cell division, elongation, and overall vegetative growth. The non-significant differences at 30 DAP suggest a delayed response to foliar-applied nutrients, whereas significant improvement at later growth stages reflects increased nutrient uptake and utilization by the plants.

Summary and Conclusion

The foliar application of boron, zinc, and manganese significantly improved plant growth parameters, including plant height, leaf count, leaf length, and stem diameter. Among all treatments, T₈ (Boron 2.0 g + Zinc 1.0 g + Manganese 2.0 g) consistently recorded the highest values at 60 and 90 DAP. The combined micronutrient application enhanced vegetative growth through improved cell division, elongation, and nutrient translocation. Non-significant differences at 30 DAP indicated delayed nutrient assimilation after foliar application. Overall, T₈ proved to be the most effective treatment for promoting vigorous growth and structural development of the crop.

References

1. Abdulnour JE, Donnelly DJ, Barthakur NN. Influence of boron supplementation on calcium absorption and developmental growth in micro-propagated plantlets of potato. Research Journal of Potato Science. 2000;43(3):287295.
2. Balázs R, Kovács K, Szabó T. Titrimetric determination of calcium carbonate equivalents in highly alkaline alluvial profiles. European Soil Science Communications. 2005;38(2):112-119.
3. Banerjee H, Sarkar S, Ray K, Rana L, Deb P, Chakraborty A, et al. Sensitivity of potato (Solanum tuberosum L.) to applied zinc across the trans-Gangetic plains of West Bengal. In: Proceedings of National Symposium on Sustainable Agriculture; 2015. p. 115-118.
4. Bari MS, Rabbani MG, Rahman MS, Islam MJ, Hoque AT. Combined effect of zinc, boron, sulphur and magnesium on the growth and productivity of potato. Pakistan Journal of Biological Sciences. 2001;4(9):1090-1093.
5. Brahmachari K, Rajib K, Suborna R, Sounda G. Influence of diverse application methods of zinc on crop productivity and produce quality in potato grown in coastal saline soil of West Bengal. Indian Agriculturist Journal. 2010;54(3-4):143-146.
6. Dissoky El RA, Abdel-Kadar AES. Evaluation of boron as a foliar nutrient spray on selected potato cultivars grown under Egyptian alluvial soil. Research Journal of Agriculture and Biological Sciences. 2013;9(5):232-240.
7. Islam MJ, Rahman S, Ahmed M. Response of Solanaceous crops to supplemental sulfur and zinc additions in subtropical profiles. Asian Agronomy Review. 1982;14(2):6571.
8. Jackson ML. Soil chemical analysis. New Delhi: Prentice Hall of India; 1967.
9. Jawad TM Al-Fadhly. Response of potato (Solanum tuberosum) to foliar zinc and manganese application under organic fertilizer conditions. Journal of Agriculture and Veterinary Science. 2016;9(4):87-91.
10. Kumar P, Pandey SK, Singh SV, Singh BP, Rawal S, Kumar D. Assessment of nutrient management strategies for potato processing cultivars. Potato Journal. 2008;35(1-2):46-52.
11. Mahdy El RE. Influence of elevated nitrogen levels on pepper plant (Capsicum annuum) growth and productivity. Mansoura (Egypt): Mansoura University; 2007.
12. Mousavi SR, Galavi M, Ahmadvand G. Influence of foliar zinc and manganese application on tuber yield, quality characteristics and mineral enrichment in potato (Solanum tuberosum L.). Asian Journal of Plant Sciences. 2007;6(8):1256-1260.
13. Muhr GR, Datta NP, Sankasubramoney H, Leley VK, Donahue RL. Soil testing in India. New Delhi: USAID Mission to India; 1965.
14. Naresh B. Evaluation of foliar boron application on vegetative growth, fruit set and quality parameters in tomato var. Pusa Ruby. Indian Journal of Hill Farming. 2002;15:109-112.
15. Natesh N, Vyakaranahal BS, Shekhargouda M, Deshpande VK. Influence of micronutrient supplementation and organic amendments on vegetative growth, seed productivity and quality in chilli. Karnataka Journal of Agricultural Sciences. 2005;18(2):55-58.
16. Olsen SR, Cole CV, Watanabe FS, Dean LA. Estimation of available phosphorus in soils by extraction with sodium bicarbonate. USDA Circular. 1954;939:1-19.
17. Panse VC, Sukhatme PV. Statistical methods for agricultural workers. New Delhi: Indian Council of Agricultural Research; 1987.
18. Pregno L, Armour J. Boron nutrition of potato cv. Sebago in North Queensland. Australian Journal of Experimental Agriculture. 1992;32(6):763-767.
19. Puzina TI. Effect of zinc sulphate and boric acid treatments on the hormonal regulation of potato plants in relation to the tuberization process. Russian Journal of Plant Physiology. 2004;51(2):209-215.
20. Rahaman MH, Halder BC, Khan MA. Effects of zinc and manganese supplementation on growth characteristics and yield of potato. Journal of Bangladesh Society for Agricultural Science and Technology. 2011;1(1-2):17-22.
21. Richards LA. Diagnosis and improvement of saline and alkali soils. USDA Handbook No. 60. Washington DC: USDA; 1954.
22. Sayed RM, Mohammad G, Goudarz A. Effect of zinc and manganese foliar applications on tuber yield, quality attributes and nutritional enrichment in potato (Solanum tuberosum L.). Asian Journal of Plant Sciences. 2007;6(8):1256-1260.
23. Subbiah BV, Asija GL. A rapid procedure for the estimation of available nitrogen in soils. Current Science. 1956;25(8):259-260.
24. Taheri N, Heidari H, Yousefi K, Mousavi SR. Effect of organic manure combined with phosphorus and zinc on seed potato yield. Australian Journal of Basic and Applied Sciences. 2011;5(8):775-800.
25. 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.