Effect of different dose of NPK with biofertilizer on growth and yield of pumpkin in semi arid conditions of Bundelkhand region

Introduction

Pumpkin (Cucurbita moschata Duch. ex Poir.) belongs to the family Cucurbitaceae and is one of the oldest cultivated vegetable crops known for its high yield potential, nutritional richness, and wide adaptability. Pumpkin fruits are rich in carbohydrates, carotenoids (especially β-carotene), vitamins A, C and E; minerals like potassium and calcium, and possess antioxidant properties. Due to these attributes, pumpkin is considered a functional food with health-promoting benefits. In India, among states highest area and production under vegetable cultivation is in West Bengal (1.49 million hectares and 28.35 million tonnes) followed by Uttar Pradesh (1.18 million hectares and 27.12 million tonnes) and Bihar (0.85 million hectares and 16.67 million tonnes) (National Horticulture Board, 2023-24). Plant nutrients are vital for sustaining plant growth and achieving maximum yield. Among these, nitrogen (N), phosphorus (P), and potassium (K) are considered primary macronutrients essential for vegetative growth, reproductive development, and yield formation. Nitrogen is a key constituent of proteins, amino acids, and chlorophyll and influences the vegetative vigor, leaf area, and photosynthetic capacity of plants. Phosphorus plays a crucial role in energy transfer (ATP synthesis), root development, early flowering, and fruit set. Potassium contributes to enzyme activation, osmotic regulation, translocation of photosynthates, and stress tolerance, which enhances both yield and fruit quality traits. Several studies have reported significant interactions between biofertilizers and chemical fertilizers. Integrated use of biofertilizers with reduced rates of NPK has been shown to enhance nutrient uptake, physiological efficiency, growth parameters, and yield attributes in several vegetable and field crops compared to sole application of chemical fertilizers.

In cucurbit crops like pumpkin, synergistic effects of biofertilizers and NPK have been associated with improved plant height, vine length, leaf area index, number of fruits per plant, average fruit weight, and total yield (Singh & Sharma, 2020) [5] .

Materials and Methods

The current study "Effect of different dose of NPK with biofertilizer on growth and yield of pumpkin in semi arid condition of Bundelkhand" was conducted during summer season of 2024-25 at the Rainfed Agriculture Research Farm, Narayan Bagh, Bundelkhand University Jhansi (Uttar Pradesh). The treatments details are as fallow The experiment was laid out in Randomized Block Design with Three replications and eight treatments. Variety used was NS9521 for Pumpkin.

Results and Discussion

Vine length recorded at 90 days after sowing (DAS) exhibited significant variation among the treatments. The maximum vine length (448.50 cm) was observed under treatment T 6 , which was significantly superior to the remaining treatments, whereas the minimum vine length (321.38 cm) was recorded in T 0 (control). The enhanced vegetative growth under T 6 might be attributed to the integrated application of recommended doses of NPK along with biofertilizers, which ensured balanced nutrient availability throughout the crop growth period. Nitrogen plays a pivotal role in chlorophyll synthesis, amino acid formation, and protein metabolism, thereby promoting vigorous vegetative growth and cell elongation. Phosphorus enhances root proliferation and energy transfer through ATP synthesis, while potassium regulates enzymatic activity and translocation of photosynthates. Similar enhancement in vine length due to integrated nutrient management in cucurbits has been reported by Kumar et al. (2013) [7] in pumpkin, Meena et al. (2015) [9] in bottle gourd, and Yadav et al. (2017) [19] in cucumber, where combined application of NPK and biofertilizers significantly improved vegetative parameters under semi-arid conditions. The number of branches per vine at 90 DAS also showed significant differences among treatments. Treatment T 3 recorded the maximum number of branches (13.49), whereas the minimum (9.65) was observed in the control (T 0 ). Increased branching under integrated nutrient application may be attributed to enhanced nitrogen availability, which stimulates lateral bud differentiation and cytokinin synthesis, leading to improved vegetative proliferation. Similar findings were reported by Singh et al. (2014) [16] and Choudhary et al. (2018) [2] , who observed that combined use of inorganic fertilizers and biofertilizers significantly increased branching and canopy development in cucurbitaceous crops. Regarding floral characters, significant variation was observed in the number of male flowers, female flowers, and sex ratio due to different nutrient treatments. The minimum number of male flowers per vine (53.81) was recorded in T 1 , whereas the maximum (80.80) was recorded in T 5 , which was statistically at par with T 2 and T 7 . The modification in sex expression and improvement in sex ratio under biofertilizer treatments may be attributed to the production of growth-promoting substances such as auxins, gibberellins, and cytokinins by microbial inoculants like PSB and Azotobacter. These substances positively influence floral differentiation and enhance female flower production. Similar observations were reported by Sharma et al. (2016) [15] in pumpkin and Verma et al. (2019) [18] in cucumber, where integrated nutrient management significantly improved flowering behaviour and reduced male: female flower ratio. The number of fruits per vine was significantly influenced by different treatments. Treatment T 3 produced the maximum number of fruits per vine (2.48), followed by T 2 , whereas the minimum (1.41) was observed in T 5 . The increase in fruit number might be due to improved nutrient uptake and better carbohydrate partitioning resulting from balanced fertilization. Integrated nutrient application enhances sink strength and fruit retention capacity. Similar improvements in fruit set under integrated nutrient management were reported by Patel et al. (2017) [11] and Kaur et al. (2020) [5] in cucurbits.

Fruit weight was also significantly affected by nutrient treatments. The maximum fruit weight (4041.0 g) was recorded in T 4 (125% recommended dose of NPK + PSB), while the minimum (3000.35 g) was observed in T 1 . The increased fruit weight under T 4 may be due to enhanced photosynthetic efficiency, better translocation of assimilates, and improved nutrient solubilization by PSB. These results are in conformity with findings of Rathore et al. (2015) [14] and Kumar et al. (2021) [6] , who reported that integrated nutrient management significantly improved fruit size and weight in pumpkin and other cucurbits. Yield parameters exhibited significant variation among treatments. Treatment T 3 recorded the maximum fruit yield per plot (30.52 kg) and the highest yield per hectare (203.50 q ha⁻¹), followed by T 7 (196.14 q ha⁻¹), whereas the lowest yield was recorded in T 1 (105.12 q ha⁻¹). The substantial increase in yield under integrated application of NPK and biofertilizers may be attributed to improved soil microbial activity, enhanced nutrient availability, better vegetative growth, improved flowering, higher fruit set, and increased fruit weight. Biofertilizers improve soil health by increasing nutrient solubilization and biological nitrogen fixation, which ultimately enhances crop productivity. Similar yield enhancement under integrated nutrient management has been reported by Meena et al. (2015) [9] , Singh et al. (2018), and Kaur et al. (2020) [5] in pumpkin and related cucurbit crops grown under semi-arid agro-climatic conditions.

Conclusion

The study clearly indicates that integrated application of NPK fertilizers with biofertilizers significantly improves growth, flowering, and yield of pumpkin under semi-arid conditions. Among the treatments, T 3 and T 4 proved most effective in enhancing fruit yield and fruit weight, respectively. Therefore, integrated nutrient management can be recommended for achieving higher productivity and sustainable pumpkin cultivation in semi-arid regions.

References

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