Intraction effect of hydrogel and integrated nutrient management on the growth parameters of green gram (Vigna radiata L.)

Introduction

Green gram (Vigna radiata L.) is an important pulse crop widely cultivated in India due to its high nutritional value, short duration, and ability to fix atmospheric nitrogen through symbiosis with Rhizobium. It is an excellent source of protein, carbohydrates, vitamins, and minerals, and contributes significantly to soil fertility and sustainable cropping systems. However, the productivity of green gram under rainfed conditions remains low because of erratic rainfall, poor soil moisture availability, and nutrient deficiencies. These constraints adversely affect crop growth, nodulation, and yield, highlighting the need for efficient moisture conservation and balanced nutrient management by Abinaya et al. (2024) [1] . Pulses play a vital role in Indian agriculture as well as in human nutrition due to their high protein content and ability to improve soil fertility through biological nitrogen fixation. In the state, green gram is cultivated over an area of about 5.07 lakh hectares, producing 3.67 lakh metric tonnes of seed with an average productivity of 725 kg ha⁻¹. Integrated Nutrient Management (INM) is a sustainable approach that integrates inorganic fertilizers, organic manures, and biofertilizers to ensure balanced nutrient supply, improve soil fertility, and enhance nutrient-use efficiency. The combined use of Recommended Dose of Fertilizers (RDF), farmyard manure (FYM), Rhizobium, and phosphate-solubilizing bacteria (PSB) improves soil microbial activity, nutrient availability, and root development. Hydrogel, a superabsorbent polymer, further enhances crop performance by increasing the soil water-holding capacity, reducing moisture stress, and maintaining continuous water availability during dry periods. Therefore, the combined application of hydrogel and INM is expected to improve growth parameters, nodulation, and overall crop performance of green gram under rainfed conditions, thereby promoting sustainable and climate-resilient agriculture by Barkha et al., (2020) [2] . Hydrogels have emerged as an effective soil amendment for improving crop productivity under moisture-deficit conditions. These superabsorbent polymers can absorb and retain large quantities of water and gradually release it to plant roots as required, thereby maintaining adequate soil moisture throughout the crop growth period. In green gram (Vigna radiata L.), hydrogel application enhances seed germination, root growth, nutrient uptake, and overall plant development by minimizing moisture stress. It also improves water-use efficiency, reduces irrigation frequency, and supports better crop performance during dry spells. Therefore, hydrogel technology offers a promising approach for sustainable pulse production, particularly in rainfed, arid, and semi-arid regions where water availability is limited (Khemshetty et al., 2024) [9] .

Materials and Methods

The field experimentation Damoh is located in the central part of Madhya Pradesh at an elevation of about 595 meters above mean sea level. Geographically, it lies between 23°09′ and 24°27′ North latitude and 79°06′ and 80°12′ East longitude. The district falls under the sub-tropical climatic zone and is characterized by a semi-arid climate with distinct summer, monsoon, and winter seasons. The average annual rainfall of the region is approximately 1,100-1,200 mm, most of which is received during the southwest monsoon period extending from late June to September. Irrigation channel 1 meter 10.

Plot border 50 cm = 0.5 meter

Fertilizers

NPK @ 20:40:40 kg ha -1 , Hydrogel, Rhizobium, PSB and FYM

The green gram variety Pusa Vishal is a high-yielding variety developed by Eklavya University, Damoh Madhya Pradesh and recommended for Eastern Hill Zone for Kharif season cultivation. Some key characteristics are green seed colour, 70-75 days duration, yield potential 11-14 q ha -1 and resistant to yellow mosaic virus. Owing to its disease resistance, synchronous maturity and wider adaptability this variety is suitable for farmers looking for a reliable and high-yielding option for the Kharif season.

Growth Characters 2.1.1 Tagging Operation

Three plants were randomly selected from each plot and tagged for detailed observations and data recording. This was done because it was not practical to study the entire plant population due to time constraints and to minimize experimental strain. The tagged plants represented the overall field condition and were used for recording various growth and yield parameters throughout the study period.

This study was conducted to assess the uniformity of plant population under different treatments. After the completion of final thinning, the number of plants per square meter was counted to determine the plant stand. The plant population was also recorded at the time of harvest from the net plots. These observations helped in evaluating the effect of different treatments on crop establishment and stand density.

Plant height of green gram was measured at 30, 60 days after sowing and at the harvesting stage. For this purpose, randomly selected plants from each plot were measured in centimeters from the ground level up to the tip of the main shoot. The average height of three tagged plants was calculated and used for statistical analysis. These observations were useful for assessing crop growth response under different treatments.

Number of Branches Plant⁻¹

The total number of branches was counted on each of the three tagged plants selected from each plot. Branches arising from the main stem were carefully recorded at the respective growth stages. The average number of branches per plant was then calculated by dividing the total number of branches by the number of sampled plants. This parameter was used to assess the vegetative growth response of green gram under different treatments.

Number of Functional Leaves Plant⁻¹

The total number of green and photosynthetically active leaves was counted from each of the three selected tagged plants in each plot. Only fully expanded and healthy leaves were considered for observation. The average number of functional leaves per plant was then calculated. This parameter helped in assessing the photosynthetic efficiency and overall vegetative growth of green gram under different treatments.

Results and Discussion

The effect of hydrogel and integrated nutrient management (INM) on initial and final plant population of green gram was found to be statistically non-significant. However, slight numerical differences were observed among treatments. Among the hydrogel levels, H₃ (Hydrogel @ 7. [3] & Choudhary et al., (2019) [4] .

Hydrogel application and integrated nutrient management (INM) significantly influenced the plant height of green gram. Among the hydrogel treatments, H₃ (Hydrogel @ 7.5 kg ha⁻¹) recorded the maximum plant height (42.27 cm) at harvest, followed by H₂, whereas the minimum height (37.10 cm) was observed under H₁ (control). Plant height increased progressively from 30 DAS to harvest, indicating continuous vegetative growth. The superior performance of hydrogel-treated plots may be attributed to improved soil moisture retention, enhanced nutrient availability, and better root growth. Among the INM treatments, I₄ (RDF + Rhizobium + PSB + FYM @ 10 t ha⁻¹) produced the tallest plants (42.03 cm), followed by I₃, while the lowest plant height was recorded under I₁ (RDF alone). Improved nutrient availability, enhanced biological nitrogen fixation, greater microbial activity, and better soil physical properties due to FYM application collectively promoted vigorous vegetative growth and significantly increased plant height. Doifode et al. (2012) [5] & Gadi et al., (2017) [6] .

Effect of Different Treatments on Number of Branches Plant⁻¹

Hydrogel application and integrated nutrient management (INM) significantly influenced the number of branches per plant in green gram. The number of branches increased progressively from 30 DAS to harvest, indicating enhanced vegetative growth. Among the hydrogel treatments, H₃ (Hydrogel @ 7.5 kg ha⁻¹) recorded the highest number of branches (5.65 plant⁻¹), while the lowest value (3.94 plant⁻¹) was observed under H₁ (control). Improved branching under hydrogel application may be attributed to better soil moisture conservation, enhanced nutrient uptake, and increased cell division. Similarly, among the INM treatments, I₄ (RDF + Rhizobium + PSB + FYM @ 10 t ha⁻¹) produced the maximum number of branches (5.47 plant⁻¹), followed by I₃, whereas I₁ (RDF alone) recorded the minimum. Enhanced nutrient availability, improved microbial activity, biological nitrogen fixation, and better soil physical conditions under integrated nutrient management collectively promoted vigorous vegetative growth and increased branching. Kankarwal et. al., (2025) [7] & Khanna et al. (2011) [8] .

Effect of Different Treatments on Number of Functional Leaves Plant⁻¹

Hydrogel application and integrated nutrient management (INM) significantly influenced the number of functional leaves per plant in green gram. Among the hydrogel treatments, H₃ (Hydrogel @ 7.5 kg ha⁻¹) recorded the highest number of functional leaves (6.43 plant⁻¹), whereas the lowest value (2.68 plant⁻¹) was observed under H₁ (control). The improved leaf production under hydrogel application may be attributed to enhanced soil moisture retention, which ensured continuous water availability, improved nutrient uptake, and promoted photosynthesis, chlorophyll synthesis, and assimilate production. Similarly, among the INM treatments, I₄ (RDF + Rhizobium + PSB + FYM @ 10 t ha⁻¹) produced the maximum number of functional leaves throughout the crop growth period, while I₁ (RDF alone) recorded the minimum. The combined application of inorganic fertilizers, FYM, and biofertilizers improved nutrient availability, biological nitrogen fixation, phosphorus solubilization, soil microbial activity, and root development, resulting in vigorous vegetative growth, enhanced canopy development, and a significantly higher number of functional leaves. Kumar et al., (2017) [10] & Kumar et al., (2025) [11] .

Conclusion

The present study demonstrated that the combined application of hydrogel and integrated nutrient management (INM) positively influenced the growth parameters of green gram under rainfed conditions. Although plant population was not significantly affected, hydrogel application at 7.5 kg ha⁻¹ (H₃) and RDF + Rhizobium + PSB + FYM @ 10 t ha⁻¹ (I₄) consistently recorded superior growth in terms of plant height, number of branches, and functional leaves. Improved soil moisture conservation by hydrogel, together with balanced nutrient supply and enhanced microbial activity under INM, promoted better nutrient uptake and vigorous vegetative growth. Therefore, the integration of hydrogel @ 7.5 kg ha⁻¹ with RDF + Rhizobium + PSB + FYM can be recommended as an effective and sustainable practice for enhancing the growth performance of green gram under rainfed agroecosystems.

References

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