Influence of post-monsoon foliar application of various nutrients on days to harvest, fruit yield and physical characteristics in mango cv. Ratna

Introduction

Mango (Mangifera indica L.), popularly known as the "King of Fruits," is one of the most economically important tropical fruit crops cultivated worldwide. India is the leading producer of mango, contributing a major share to global production owing to its wide genetic diversity and favourable agro-climatic conditions. Besides its economic importance, mango is highly valued for its excellent flavour, attractive appearance, pleasant aroma, and high nutritional value. Among the commercially cultivated mango cultivars, Ratna, a hybrid of Alphonso × Neelum developed at Dr. Balasaheb Sawant Konkan Krishi Vidyapeeth, Dapoli, has gained considerable importance in the Konkan region of Maharashtra. The cultivar combines the superior fruit quality of Alphonso and the regular bearing habit of Neelum. Ratna produces attractive medium-sized fruits with fibreless pulp, pleasant flavour, good keeping quality, and comparatively lower incidence of spongy tissue disorder, making it suitable for both fresh consumption and processing. However, maintaining consistent fruit quality under changing environmental conditions remains a major challenge, particularly in the humid tropical climate of the Konkan. The heavy monsoon rainfall, high relative humidity, and lateritic soils. Most mango orchards are located on hilly terrains and lateritic plateaus where soil depth, water-holding capacity, and nutrient availability are often limited. These conditions pose challenges for maintaining high productivity and fruit quality. In recent years, climatic abnormalities such as irregular rainfall, cyclones, early pre-monsoon showers, delayed monsoon withdrawal, and temperature fluctuations have become more common. These conditions adversely affect flowering, fruit set, fruit retention, and fruit development, resulting in considerable yield losses. The major limitations of mango cv. Ratna is its tendency for late flowering and delayed fruit maturity, the cultivar requires a relatively longer period from fruit set to maturity, approximately 130 days, such effects are more evident in mango cv. Ratna, where delayed flowering often leads to delayed fruit maturity and harvesting. Compared to many other commercial cultivars.

Foliar nutrition has emerged as an efficient and economical approach for supplying essential nutrients directly to plant tissues during critical growth stages. Compared with soil application, foliar feeding ensures rapid nutrient absorption, minimizes nutrient losses through leaching, and improves nutrient use efficiency. Among the essential macronutrients, nitrogen, phosphorus, and potassium play crucial roles in determining fruit quality. Nitrogen supports chlorophyll formation, photosynthesis, and protein synthesis; phosphorus facilitates energy transfer and metabolic activities associated with fruit growth; while potassium regulates carbohydrate metabolism, enzyme activation, osmotic balance, sugar translocation, pigment synthesis, and accumulation of soluble solids in fruits. Consequently, foliar application of these nutrients during the post-monsoon period may substantially improve the physical and biochemical quality attributes of mango fruits. Potassium nitrate (KNO₃), containing both nitrate nitrogen and potassium, has been widely recognized as an effective foliar nutrient for improving fruit development and quality in mango. Potassium enhances translocation of photosynthates from leaves to developing fruits, leading to increased fruit weight, higher pulp content, improved total soluble solids, enhanced sugar accumulation, and better colour development. Similarly, phosphorus-containing compounds contribute to energy metabolism and carbohydrate utilization during fruit development, whereas balanced nitrogen nutrition supports sustained physiological activity without excessive vegetative growth. Nitrogen, phosphorus, and potassium are the major nutrients involved in flowering and fruit development. Nitrogen is essential for chlorophyll formation, protein synthesis, and vegetative growth. Phosphorus plays an important role in energy transfer and reproductive development, while potassium regulates enzyme activity, osmotic balance, and carbohydrate translocation, thereby improving fruit quality. Potassium nitrate (KNO₃), containing about 14 per cent nitrogen and 46 per cent potassium, is widely used in mango cultivation as both a nutrient source and a flowering inducer. It is known to stimulate nitrate reductase activity and ethylene production, which help promote flowering. Likewise, ortho-phosphoric acid (H₃PO₄) supports flowering through its role in energy transfer processes. Normally, mango flowering begins after the withdrawal of monsoon rains and the onset of dry weather during October and November. However, in mango cv. Ratna, recent climatic irregularities have frequently disturbed this flowering pattern. Higher temperatures during the post-monsoon period often encourage vegetative flushing instead of flowering. Since these vegetative shoots require additional time to mature, flowering and fruit development are delayed, ultimately affecting harvest time and market returns. Therefore, management practices that promote timely flowering and fruiting are becoming increasingly important. Besides improving flowering, foliar nutrition also contributes to better fruit retention, yield, and fruit quality. Malshe et al. (2022) [11] reported that potassium nitrate sprays significantly improved fruit retention and yield in Alphonso mango under South Konkan conditions.

Materials and Methods

The present investigation entitled "Effect of Post-Monsoon Foliar Nutrition on Assessment of Flowering and Fruit Set of Mango (Mangifera indica L.) cv. Ratna. The experiment was conducted during 2021-2023 at the Mother Orchard of mango (Mangifera indica L.) cv. Ratna, Department of Fruit Science, College of Horticulture, Dr. Balasaheb Sawant Konkan Krishi Vidyapeeth, Dapoli, Ratnagiri, Maharashtra, India. The experimental orchard is located at 17°45′ N latitude and 73°12′ E longitude, at an altitude of 240 m above mean sea level. The region experiences a humid tropical climate characterized by an average annual rainfall of approximately 3500 mm, mean relative humidity of about 78%, and lateritic sandy clay loam soil with a pH ranging from 5.6 to 6.5. The experiment was carried out on 30-year-old healthy and uniformly maintained mango trees of cv. Ratna planted at a spacing of 10 × 10 m. The experiment was laid out in a Randomized Block Design (RBD) consisting of nine treatments with three replications, each replication comprising two trees, resulting in a total of 54 experimental trees. The experiment consisted of nine treatments: T₁ (control), T₂ (urea 1%), T₃ (urea 3%), T₄ (potassium nitrate 1%), T₅ (potassium nitrate 3%), T₆ (ortho-phosphoric acid 0.5%), T₇ (ortho-phosphoric acid 1%), T₈ (monopotassium phosphate 1%), and T₉ (monopotassium phosphate 3%). The first foliar spray was applied after the emergence of the post-monsoon vegetative flush during October-November, followed by a second spray 15 days later. Nutrient solutions were freshly prepared on the day of application and sprayed uniformly using a power-operated sprayer. Approximately 10 L of spray solution per tree was applied according to the respective treatment. Trees under the control treatment received no foliar nutrient application. All experimental trees were maintained under uniform orchard management practices throughout the study period following the recommended package of practices of Dr. Balasaheb Sawant Konkan Krishi Vidyapeeth. Farmyard manure at 50 kg tree⁻¹ and the recommended fertilizer dose of 1.5 kg N, 0.5 kg P₂O₅ and 1.0 kg K₂O tree⁻¹ were applied during July in circular trenches opened at half the canopy radius. Standard intercultural operations, including weed management, orchard sanitation, plant protection measures and irrigation during fruit development, were uniformly adopted for all treatments.

Results and Discussion

Days required for harvesting from flowering

The data on days required for harvesting from flowering in mango cv. Ratna are presented in Table 1. The pooled analysis revealed that the significantly minimum number of days required for harvesting from flowering was recorded in T5 (Potassium nitrate 3%) (116.84 days), which was followed by T 4 (Potassium nitrate 1%) (123.58 days). Treatment T 2 (Urea 1%) (143.37 days) and T 3 (Urea 3%) (143.68 days) recorded comparatively more number of days for harvesting, whereas the maximum number of days required for harvesting from flowering was recorded in T 1 (Control) (156.45 days). The results of the present investigation indicated that postmonsoon foliar application of nutrients significantly influenced the number of days required for harvesting from flowering in mango cv. Ratna. Among different treatments, foliar application of potassium nitrate (3%) recorded minimum number of days required for harvesting compared to other treatments and control. The reduction in days required for harvesting observed under potassium nitrate treatments might be attributed to enhanced nitrogen assimilation and improved potassium-mediated translocation of carbohydrates towards developing fruits, which accelerated fruit growth and maturity. Potassium plays an important role in enzyme activation and regulation of metabolic activities associated with starch hydrolysis and sugar accumulation, thereby promoting early fruit development and advancement of maturity. Earlier fruit maturity due to foliar application of potassium nitrate has also been reported by Rajan et al. (2017) [15] in mango, who observed that nitrate-based foliar nutrition enhanced fruit development rate and shortened crop duration. The comparatively reduced harvesting duration observed with monopotassium phosphate (3%) treatment might be attributed to the combined role of phosphorus and potassium in energy transfer reactions and assimilate movement towards developing fruits. Adequate phosphorus availability enhances ATP synthesis and supports rapid cell division during early fruit development, thereby advancing fruit maturity. Similar findings were reported by Shinde et al. (2019) [18] in mango. [13] in mango, who observed reduced fruit development duration due to improved assimilate partitioning towards reproductive sinks. The comparatively shorter duration observed under orthophosphoric acid (0.5%) treatment might be attributed to enhanced phosphorus availability supporting ATP-dependent metabolic activities required for rapid fruit growth and maturation. Adequate phosphorus nutrition improves energy transfer reactions and accelerates reproductive development processes. Similar findings were reported by Sharma et al. (2020) [22] in mango. Moderate reduction in harvesting duration under monopotassium phosphate treatments might be due to the synergistic role of phosphorus and potassium in improving sink strength and assimilate transport efficiency during fruit development stages. Similar observations were reported by Bairwa et al. (2019) [1] in mango cv. Amrapali. The comparatively longer duration recorded under control treatment might be attributed to slower fruit development due to limited availability of nutrients required for supporting metabolic activities associated with fruit enlargement and maturity. Similar delay in harvesting duration under untreated trees has been reported by Kumar and Kumar (2022) [9] in mango. [6] in mango. The comparatively higher number of fruits recorded under orthophosphoric acid treatments might be attributed to improved phosphorus availability supporting energy transfer reactions and ATP synthesis required during reproductive development and fruit growth processes. Adequate phosphorus nutrition enhances sink activity and reduces premature fruit drop. Similar findings were reported by Gurjar et al. (2018) [7] in mango. Moderate increase in number of fruits per tree observed under potassium nitrate treatments might be attributed to improved carbohydrate translocation and regulation of enzymatic activities associated with fruit development. Potassium plays an important role in maintaining osmotic balance and enhancing assimilate transport towards developing fruits, thereby improving fruit retention up to harvest stage. Similar observations were reported by Bhowmick et al. (2020) [4] in mango. [12] in mango cv. Kesar. The comparatively higher fruit yield recorded under urea (3%) treatment might be attributed to improved nitrogen availability supporting synthesis of chlorophyll, proteins and enzymes involved in reproductive development and fruit growth. Adequate nitrogen nutrition enhances leaf area development and photosynthetic efficiency, thereby increasing assimilate supply to developing fruits. Similar findings were reported by Sarkar et al.

(2019) [17] in mango. Improved fruit yield observed under orthophosphoric acid (0.5%) treatment might be due to enhanced phosphorus availability supporting ATP-mediated metabolic activities and energy transfer processes required during flowering, fruit set and fruit development stages. Phosphorus plays an important role in strengthening reproductive sink activity and improving overall productivity of mango trees. Similar observations were reported by Kumar et al. (2018) [8] Malshe et al. (2022) [11] and Pilli et al.

(2025) [14] in mango. The comparatively lower fruit yield recorded under control treatment might be attributed to absence of supplemental nutrient supply required during critical reproductive stages, resulting in reduced assimilate availability and lower fruit retention. Similar reduction in yield under untreated trees has also been reported by Beniwal et al. (2021) [2] in mango.

The data on fruit weight at harvest stage as influenced by postmonsoon foliar application of nutrients in mango cv. Ratna are presented in Table 5 On pooled basis, the significantly highest average fruit weight was recorded in T 5 (Potassium nitrate 3%) (464.13 g) followed by T 4 (Potassium nitrate 1%) (445.49 g) and T 6 (Ortho-phosphoric acid 0.5%) (414.70 g). Treatment T 7 (Ortho-phosphoric acid 1%) (389.62 g) and T 3 (Urea 3%) (387.80 g) recorded comparatively moderate fruit weight, whereas the minimum fruit weight was recorded in T 2 (Urea 1%) (369.30 g) followed by T 1 (Control) (371.21 g). Post-monsoon foliar application of nutrients significantly influenced average fruit weight in mango cv. Ratna. The highest fruit weight recorded under potassium nitrate (3%) treatment might be attributed to improved nitrogen assimilation and enhanced potassium-mediated translocation of carbohydrates towards developing fruits, which promoted cell division and cell enlargement during fruit growth stages. Potassium plays a crucial role in regulating osmotic potential, enzyme activation and transport of photosynthates from source leaves to developing fruits, thereby improving sink strength and enhancing fruit size and weight. Increased fruit weight following foliar potassium nutrition has also been reported by Yeshitela et al. (2018) [21] in mango. The comparatively higher fruit weight observed under potassium nitrate (1%) treatment might also be attributed to improved metabolic activity and efficient utilization of assimilates during fruit enlargement stages. Similar improvement in fruit weight due to foliar potassium application has been reported by Rana et al. (2021) [16] in mango. Improvement in fruit weight observed under orthophosphoric acid (0.5%) treatment might be attributed to enhanced phosphorus availability supporting ATP-mediated metabolic processes required for rapid cell division and fruit development. Phosphorus plays an important role in energy transfer reactions and synthesis of nucleic acids necessary for fruit growth. Similar findings were reported by Singh et al. (2025) [19] in Mango cv. Dasheri. The comparatively lower fruit weight recorded under control treatment might be attributed to reduced availability of nutrients required during fruit enlargement stages, resulting in limited assimilate supply to developing fruits. [10] in mango. Moderate improvement observed under monopotassium phosphate treatments might be due to the combined role of phosphorus and potassium in improving sink strength and metabolic activity of developing fruits. Similar observations were reported by Singh et al. (2021) [16] in mango. The increase in fruit diameter observed under potassium nitrate treatments might be attributed to enhanced potassium-mediated transport of carbohydrates and regulation of cellular turgor pressure during fruit enlargement stages. Potassium plays an important role in maintaining osmotic balance and promoting radial expansion of fruit tissues. Similar improvement in fruit diameter following foliar potassium application has been reported by Bhanderi et al. (2018) [13] in mango. The comparatively higher fruit diameter recorded under urea (3%) treatment might be attributed to improved nitrogen availability supporting synthesis of structural proteins and enzymes associated with fruit enlargement processes. The comparatively lower fruit diameter recorded under control treatment might be attributed to reduced assimilate availability during fruit development stages due to absence of supplemental nutrient supply. Similar findings were reported by Chaudhary et al. (2022) [5] in mango.

Conclusion

The result of the present investigation clearly indicated that the post-monsoon foliar application of nutrients significantly influenced days required for harvesting from flowering and from fruit set, Number of fruits per tree, Fruit yield (Kg/tree) of mango cv. Ratna. Among different nutrient treatments, foliar application of potassium nitrate at 3 per cent recorded least days taken for harvesting from flowering, least days taken for harvesting from fruit set, highest fruit yield (Kg/tree), Average fruit weight while highest number of fruits per tree recorded in treatment T3 Urea 3%. The study established that post-monsoon foliar application of potassium nitrate at 3% is an effective for least days taken for harvesting from flowering and from fruit set, highest fruit yield (Kg/tree), Average fruit weight in mango cv. Ratna under the agro-climatic conditions of the Konkan region

References

1. Bairwa HL, Mahawer LN, Shukla AK. Effect of foliar nutrient application on growth and fruit development of mango cv. Amrapali. Int J Chem Stud. 2019;7(4):2650-2654.
2. Beniwal BS, Yadav PK, Meena RK. Effect of nutrient sprays on yield attributes of mango under semi-arid conditions. Int J Agric Sci. 2021;13(1):210-214.
3. Bhanderi DR, Tank RV, Patel NL. Effect of foliar nutrient sprays on fruit growth and yield attributes of mango. Int J Chem Stud. 2018.
4. Bhowmick N, Ghosh B, Banik BC. Effect of foliar nutrient application on reproductive behaviour and yield attributes of mango. Int J Chem Stud. 2020;8(2):1565-1569.
5. Chaudhary V, Meena RK, Singh R. Effect of nutrient sprays on fruit growth parameters of mango under semi-arid conditions. J Pharmacogn Phytochem. 2022.
6. Dutta P, Banik AK, Dhua RS. Effect of foliar nutrition on fruit retention and yield of mango cv. Himsagar. J Crop Weed. 2017;13(2):45-49.
7. Gurjar PS, Rana DK, Singh R. Influence of foliar phosphorus nutrition on flowering and fruiting behaviour of mango. J Pharmacogn Phytochem. 2018;7(5):2148-2152.
8. Kumar P, Singh AK, Yadav RK. Influence of phosphorus nutrition on yield and fruit development of mango cv. Dashehari. Int J Curr Microbiol Appl Sci. 2018;7(4):29512956.
9. Kumar R, Kumar S. Effect of nutrient sprays on fruit growth dynamics and maturity behaviour of mango. Indian J Agric Res. 2022;56(4):451-456.
10. Mahmood T, Hassan Z, Ali A. Role of potassium nutrition in improving fruit growth characteristics and nutrient accumulation in mango. J Plant Nutr. 2020;43(12):18351843.
11. Malshe KV, Burondkar MM, Kulkarni VJ. Influence of postflowering foliar nutrient application on yield and quality attributes of mango cv. Alphonso. J Exp Agric For. 2022;4(1):18-25.
12. Muddanesha S, Kumar N, Reddy YTN. Influence of foliar application of nutrients on physiological parameters influencing flowering and yield of mango cv. Kesar. Int J Chem Stud. 2022;10(2):1156-1161.
13. Ngullie E, Tank RV, Bhanderi DR. Effect of foliar application of nutrients on fruit development and maturity behaviour of mango (Mangifera indica L.). Int J Agric Sci. 2016;8(61):3467-3470.
14. Pilli K, Venkanna Y, Rao BB, Srinivas A, Kumar TV, Navya B, et al. Impact study on foliar spray of potassium nitrate on yield and economics of mango cultivation through on-farm trials and front-line demonstrations in Telangana. Int J Curr Microbiol Appl Sci. 2025;14(1):302-307.
15. Rajan S, Kumar R, Saxena P. Influence of nutrient sprays on fruit development and maturity behaviour in mango (Mangifera indica L.). Indian J Hortic. 2017;74(2):245-250.
16. Rana DK, Singh R, Gurjar PS. Influence of foliar nutrient sprays on fruit size and yield attributes of mango cv. Dashehari. J Pharmacogn Phytochem. 2021;10(2):21502154.
17. Sarkar S, Mishra DS, Singh VK. Effect of foliar nutrition on yield and quality attributes of mango (Mangifera indica L.). J Appl Nat Sci. 2019;11(4):865-870.
18. Shinde MP, Burondkar MM, Kulkarni VJ. Effect of foliar nutrient application on growth, yield and maturity behaviour of mango cv. Alphonso. J Appl Hortic. 2019;21(1):45-50.
19. Singh S, Deshmukh UB, Paikra MS, Singh J, Nishad D, Gupta N, et al. Study the effect of foliar spray of different chemicals on flowering and fruiting in mango (Mangifera indica L.) cv. Dashehari. Int J Biochem Res Rev. 2025;34(1):116-122.
20. Singh VK, Kumar R, Yadav RK. Influence of environmental factors on phenological development of mango cultivars under subtropical climate. Indian J Hortic. 2021;78(3):412417.
21. Yeshitela T, Robbertse PJ, Stassen PJC. Effect of foliar potassium nutrition on fruit growth and yield attributes of mango (Mangifera indica L.). Acta Hortic. 2018;1208:203210.
22. Gautam R, Sharma M. 2019-nCoV pandemic: A disruptive and stressful atmosphere for Indian academic fraternity. Brain, behavior, and immunity. 2020 Apr 11;88:948.