Efficacy of Fasal Amrit hydrogel on growth, yield and economics of Green Gram (Vigna radiata L.) under South Gujarat Conditions, India

Introduction

India is the largest producer, consumer and importer of pulses, which serve as a major source of protein for a large section of the population. Among different dietary protein sources, pulses are consumed more frequently, highlighting their vital role in daily food habits. Pulses contribute about 11% to the total protein intake in India (Reddy, 2010) [16] . Green gram (Vigna radiata) is one of the most important pulse crops, accounting for nearly 40% of total pulse production. It is consumed in multiple forms-whole grain, sprouts and split dalmaking it an integral part of Indian diets. India is the leading global producer of green gram, predominantly grown in arid and semi-arid regions where water scarcity is a major challenge, contributing around 10% of the country's total pulse output. During 2020-21, green gram was cultivated on approximately 5.13 million hectares with a production of 3.08 million tonnes and an average productivity of 601 kg ha⁻¹ (DES, 2021). In Gujarat, it covered 0.15 million hectares, yielding 0.11 million tonnes with an average productivity of 712 kg ha⁻¹. The major producing states include Rajasthan, Karnataka, Madhya Pradesh, Haryana, and Gujarat. Specifically, in Bharuch district, green gram cultivation covered 4,985 hectares with an average productivity of 987 kg ha⁻¹ (DAO, Bharuch, 2023). Despite its significance, a considerable yield gap has been reported in Bharuch, primarily due to technological and extension limitations (Patil et al., 2015) [13] . Moreover, yellow vein mosaic disease poses a major challenge, often becoming more severe under water stress conditions. In this context, water management technologies assume critical importance. Hydrogels-superabsorbent polymers capable of holding several times their weight in water-have emerged as a promising option to improve soil moisture availability and reduce irrigation frequency (Allahdadi et al., 2005, El-Hady and Camilia, 2006) [4, 8] . By absorbing and releasing water gradually, hydrogels help mitigate the effects of drought stress, thereby enhancing crop growth and yield (Dass et al., 2013; Rehman et al., 2011) [5,17] . Considering the recurring water scarcity in summer cultivation, the present study was undertaken to evaluate the effectiveness of hydrogel Fasal Amrit in improving the growth, productivity, and water-use efficiency of summer green gram. Fasal Amrit is an organic superabsorbent polymer made from bio-waste by EF Polymer Pvt. Ltd., Rajasthan, India.

Materials and Methods

The experiment was conducted at Krishi Vigyan Kendra, BAIF Campus, Chaswad, Bharuch district in south Gujarat (21 0 34'31.44 N latitude, 73 0 34'31.44 E longitude, and an elevation of 135 m above mean sea level) during summer 2024 and 2025. The climate of the region is semi-arid with hot summers and mild winters. The mean annual rainfall received at Chaswad is 1000 mm. Nearly, 95% of the total precipitation is received during the southwest monsoon season (June to September) and the remaining period of the year is generally dry. During the summer months (April, May and June), temperatures rise to 40 0 C. The soil is a fine textured clay loam. The initial soil sample was collected before laid out of the research trial. The initial status of soil is given in Table 1. Data were collected on soil, plant growth and yield parameters. These parameters were compared across the different treatment groups and the control. The cost of cultivation per hectare was calculated for the individual treatment based on inputs used and the prevailing market price of the produce. Gross monetary returns were estimated by multiplying economic yield with the current market price of green gram. Net returns (Rsha -1 ) were calculated by deducting the cost of cultivation from gross monetary returns for each treatment. Benefit cost (B:C) ratio was calculated by dividing gross returns with the cost of cultivation.

The soil moisture was measured at seven-days interval with the help of a soil moisture indicator (at 0-15 cm depth). The quantity of irrigation water consumed by crop was measured by using "V-notch weir" device. The soil samples were collected from each treatment after harvest of crop and analysed for fertility parameters. The samples of grain and stalk of green gram were digested with the help of sulphuric salicylic acid for analysis of N and diacid (HClO 4 + HNO 3 ) for analysis of P and K. Total nitrogen content was estimated by Kjeldahl method while, phosphorus and potash were determined using a spectrophotometer and flame photometer, respectively.

Statistical Analysis

Data on plant growth and yield were analysed by two-way analysis of variance (ANOVA) as per the model suggested by Panse and Sukhatme (2000). The data recorded was analysed using SPSS 16.0 package software as per design of the experiment.

Results and Discussion

The growth and yield of green gram was assessed to understand the effect of Fasal Amrit at two levels and varying doses of RDF. The details are described in the following sub-sections.

Effect of Fasal Amrit on growth parameters of green gram

The data on vegetative growth parameters, namely plant height, number of leaves, and number of branches, revealed significant improvement with the integration of Fasal Amrit and RDF compared to RDF alone (Table 2). Plant height at 20 and 40 DAS remained statistically non-significant across treatments and years, indicating uniform early growth. However, at harvest, treatments differed significantly, with T 3 (Fasal Amrit 20 kg ha⁻¹ +100% RDF) recording the maximum height (53.20 cm), which was markedly higher to RDF alone (40.08 cm) and T 8 (43.13 cm). Other Fasal Amrit treatments showed intermediate plant heights (47.57-48.55 cm) and remained statistically at par. The year and Y × T interaction was non-significant, reflecting stable performance across seasons. For number of leaves per plant, T 3 consistently produced the maximum number of leaves (9.97 at 20 DAS; 24.21 at 40 DAS; 36.57 at harvest), followed by Fasal Amrit treatments at reduced RDF levels, all of which were significantly superior to RDF alone (8.55, 18.96, and 24.27 leaves at respective stages). A significant year effect was recorded at 40 DAS and harvest, with higher leaf counts in 2024 and2025, possibly due to favourable climatic conditions, while the Y × T interaction remained non-significant. Number of branches per plant also exhibited a similar trend (Table 3). At 40 DAS, significant differences were noted in 2024 and pooled data. T 3 recorded the highest pooled branches (7.20), which was significantly superior to RDF alone (6.07). At harvest, T 3 again dominated (9.69 branches), significantly exceeding T 1 (7.36), while other Fasal Amrit treatments (8.43-8.57) remained statistically at par. Reduction in RDF levels up to 20% (T 4 -T 9 ) did not significantly reduce plant height, leaf number, or branching, highlighting the potential of nutrient saving without compromising growth. The improvement in these traits may be attributed to enhanced moisture retention and nutrient use efficiency, supporting cell division, elongation, and leaf expansion. These findings corroborate earlier reports by Al-Harbi et al. (1999) [3] and Akhter et al. (2004), who emphasized the role of hydrogel polymers and integrated nutrient management in sustaining higher vegetative growth and branching ability under field conditions. Kunjir et. al. 2022 also stated that, the application of SPG 1818 hydrogel @20 kg along with 2 kg of vermicompost was recorded significantly higher growth and yield parameters such as plant height (97.2cm), branches per plant (2.5), pods per plant (2.29), leaves per plant (18.3), total pods per plot (540.3), root length (30.4 cm), root weight (41.5g), and shoot weight (142.1g) as compared to other treatments.

Effect of Fasal Amrit on yield parameters and yield of green gram

Application of Fasal Amrit in combination with RDF levels significantly influenced yield attributes of the crop (Table 4).

The number of pods per plant was markedly higher under Fasal Amrit treatments compared with RDF alone. Among the treatments, Fasal Amrit @ 20 kg ha⁻¹ + 100% RDF (T 3 ) recorded the maximum number of pods per plant (18.30, pooled) followed by T 5 (15.60), whereas the minimum was observed under RDF alone (10.37). A similar trend was evident for the number of grains per pod, where T 3 produced significantly more grains (8.37) compared with RDF (6.17). Pod length was also enhanced due to Fasal Amrit application, with the longest pods (6.05 cm) recorded in T 3 , while RDF alone resulted in the shortest pods (5.21 cm). Test weight showed significant improvement with the application of Fasal Amrit, the highest being recorded under T 3 (4.15 g), which was statistically superior to RDF (3.76 g). Year effect was found to be significant only for test weight, suggesting some influence of seasonal variation on grain filling, whereas year × treatment interaction remained non-significant across all traits, indicating consistency of treatment performance over the years. These results clearly demonstrate that the application of Fasal Amrit, particularly at 20 kg ha⁻¹ along with RDF, substantially improved reproductive parameters such as pods per plant, grains per pod, pod length and test weight. The application of Fasal Amrit in combination with RDF significantly enhanced grain and straw yields compared to RDF alone (Table 5). Pooled grain yield data revealed that the maximum yield (1556.42 kg ha⁻¹) was obtained with Fasal Amrit @ 20 kg ha⁻¹ + 100% RDF (T 3 ), which was significantly superior to RDF (1012.78 kg ha⁻¹) and other reduced RDF treatments. The lowest yield was recorded in RDF alone. Similarly, pooled straw yield was highest in T 3 (3559.03 kg ha⁻¹), followed by T 2 (3327.92 kg ha⁻¹) and T 4 (3208.89 kg ha⁻¹). RDF alone recorded the lowest straw yield (2583.28 kg ha⁻¹).

The improvement in straw yield with Fasal Amrit, application could be attributed to better vegetative growth and higher biomass accumulation, which also translated into enhanced grain yield. The year effect was significant for both grain and straw yields, while the year × treatment interaction was nonsignificant, indicating consistent treatment response across years. Overall, the results indicated that Fasal Amrit @ 20 kg ha⁻¹ + RDF (T 3 ) was the most effective treatment in enhancing both grain and straw yields. Importantly, treatments with reduced RDF (85-90%) in combination with Fasal Amrit also produced yields significantly higher than RDF alone, suggesting the potential of Fasal Amrit to partially substitute chemical fertilizers without compromising productivity. Super absorbent polymers enhanced yield attributes by improving cell membrane development, chlorophyll, protein content, and CO₂ fixation through prolonged stomatal opening, consistent with findings in mustard (Rathore et al., 2019) [15] . Similar findings reported were consistent with the results obtained by Roy et al. (2019) [18] in wheat.

Effect of Fasal Amrit on economics of green gram cultivation

The economic analysis of different treatments (Table 6) revealed considerable variation in gross returns, net returns, and benefitcost ratio (BCR) across the two years as well as in pooled results. Among the treatments, Fasal Amrit @ 20 kg/ha + RDF (T 3 ) recorded the highest gross returns (₹1,29,141/ha pooled), net returns (₹71,358/ha pooled), and BCR (2.23), followed closely by Fasal Amrit @ 15 kg/ha + RDF (T 2 ) with pooled gross returns of ₹1,18,304/ha, net returns of ₹65,220/ha, and BCR of 2.23. The treatment Fasal Amrit @ 15 kg/ha + RDF 90% (T 4 ) also performed well, showing a BCR of 2.17 in pooled data. In contrast, the lowest returns were obtained under Fasal Amrit @ 20 kg/ha + RDF 80% (T 9 ), which recorded pooled gross returns of ₹97,778/ha, net returns of ₹40,912/ha, and a BCR of 1.72. Statistical analysis indicated that the differences in gross and net returns were significant at the 5% level during both years and in pooled data, whereas BCR showed significance only in the second year and pooled results. Overall, the study demonstrates that the application of Fasal Amrit particularly at 20 kg/ha, in combination with 100% RDF, offers the most favourable economic returns without compromising input efficiency. On the other hand, reducing RDF below 90% led to reduced profitability, implying that partial substitution of fertilizers with Fasal Amrit is feasible only up to a limited extent. The results are in agreement with the findings of Li and Zhang 2010 [11] and Singh et al. (2018) [19] .

Effect of Fasal Amrit on the uptake of nutrients by green gram

The data presented in Table 7 shown the mean effect of different treatments of Fasal Amrit on the moisture content, crude protein and nutrient composition of both grain and straw during 2024 and 2025. The results revealed considerable variation among the treatments for all measured parameters. Moisture content in grain ranged from 3.27% (T₆) to 5.94% (T₂), while in straw it varied from 6.72% (T₉) to 9.62% (T₄). The crude protein content in grain was observed to be highest with Fasal Amrit 20 kg/ha + 100% RDF (24.07%), followed by T₇ (23.94%). In straw, the crude protein content ranged from 6.26% (T₃) to 8.38% (T₂), indicating a moderate response of straw protein accumulation to different treatments. The nitrogen concentration in grain varied between 3.53% (T₁) and 3.85% (T₃), while in straw it ranged from 1.01% to 1.34%. This can be attributed to the enhanced microbial activity and nutrient mobilization facilitated by Fasal Amrit, which likely improved nitrogen uptake and assimilation into protein in the grain. Phosphorus content in grain was highest in T₁ (1.87%), closely followed by T₂ (1.95%). In straw, the phosphorus content varied from 0.53% (T₃) to 0.66% (T₁). Similarly, potassium content in grain was highest under T₁ (1.18%) and lowest under T₈ (0.63%), whereas in straw, potassium ranged from 0.37% (T₆) to 0.47% (T₁). Phosphorus and potassium content in grain and straw also showed positive responses under Fasal Amrit treatments. The microbial consortia and nutrient-solubilizing components of the formulation may have enhanced P and K availability in the rhizosphere, facilitating greater translocation to grain. The results are consistent with the findings of Mandal et al. (2015) [12] and Rathore et al. (2020) [14] .

Effect of Fasal Amrit on soil properties

The application of Fasal Amrit hydrogel combined with RDF levels led to improvements in soil nutrient availability, particularly nitrogen, phosphorus and potassium. The mean soil data in Table 8 revealed that soil pH remained stable, ranging from 6.16 to 6.39, while EC varied slightly (0.16-0.23 dSm -1 ), indicating salinity remained within safe limits. The organic carbon content (OC) increased in most treatments, peaking at 0.65% in T 3 and T 4 . The soil organic matter (SOM) content increased significantly with increasing Fasal Amrit rates, as it is derived from organic materials. Available N improved with the highest level in T 7 (378.83 kgha -1 ), and available P content ranged from 35.46 kg/ha (T 7 ) to 49.9 kg/ha (T 9 ). The potassium availability improved, especially in T 3 (184.65 83 kgha -1 ). Micronutrient levels also improved modestly, contributing to overall better soil fertility.

Effect of Fasal Amrit on irrigation water requirement in green gram

Table 9 presents an overview of the irrigation water management across different treatments and their efficiency in water conservation. Treatment T 1 , the RDF (20:40:40 kgha -1 ), followed the standard practice and required five irrigations. All other treatments (T 2 through T 9 ) involved four irrigations. This is, indicating that by application of Fasal Amrit, helps to reduce one irrigation without affecting the crop yield. The total irrigation water applied varies across treatments, the control treatment (T [10] opined that two irrigations in wheat can be saved by the application of hydrogel without compromising the grain yield. Water savings, calculated as the difference between the control treatment (T 1 ) and the treatments are ranged between 8.24-9.23 acre-inch compared to control and treatments with the application of Fasal Amrit. This significant reduction in water use demonstrates the effectiveness of integrating Fasal Amrit and adjusted RDF levels in reducing the water requirement for crop growth. Fasal Amrit 20 kg/ha + 100% RDF (T 3 ) saved 9.23 acre-inch the maximum water savings across all treatments with maximum water saving of 20.44% compared to control (T 1 ) treatments.

Conclusion

The study demonstrated that the application of Fasal Amrit in the cultivation of summer green gram significantly enhance soil moisture retention, improve plant growth, and increase yield, making it a valuable input for sustainable agriculture in droughtprone areas. The data clearly demonstrated that applying Fasal Amrit at both 15 kgha -1 and 20 kgha -1 , combined with either full or reduced RDF, is the most profitable treatment, providing the highest gross and net income along with the best benefit-cost ratio and substantial water savings in irrigated agriculture.

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