Economic evaluation of hydrogel and graded levels of fertigation in mulberry cultivation and cocoon production

Introduction

Mulberry (Morus alba L.) is the sole food plant for the silkworm (Bombyx mori L.) and forms the foundation of the sericulture industry, which supports millions of rural livelihoods in India. Productivity and quality of mulberry leaves directly influence silkworm growth, cocoon yield, and silk quality, making efficient crop management essential for sustaining sericulture profitability (Bongale et al., 1997) [4] . Among the various agronomic factors, water and nutrient management play a decisive role in determining mulberry leaf yield and nutrient composition (Singh et al., 2012) [13] . Traditional methods of irrigation and fertilizer application in mulberry are often characterized by excessive water use, uneven nutrient distribution, and substantial losses through leaching and volatilization, particularly in light-textured soils of dry and semi-arid regions (Thomas et al., 2024) [14] . These inefficiencies not only reduce nutrient use efficiency but also increase the cost of cultivation, thereby lowering net returns to farmers. Micro-irrigation systems, particularly drip irrigation combined with fertigation have shown to improve water use efficiency and fertilizer recovery by delivering nutrients directly to the root zone in precise quantities (Bandyopadhyay et al., 2020) [3] . However, water stress remains a major constraint in mulberry cultivation, particularly under erratic rainfall and limited irrigation resources. In this context, super-absorbent polymers or hydrogels have emerged as promising soil amendments for improving soil moisture retention and reducing irrigation frequency. Hydrogels can absorb and store large quantities of water and gradually release it to plant roots, thereby mitigating moisture stress and enhancing water productivity (Neethu et al., 2018) [11] . Starch-based hydrogels have been widely evaluated for their biodegradability, compatibility with crops and positive effects on soil physical properties, (Ranganatha et al., 2025) [12] demonstrated that hydrogel application and fertigation improve crop yield and water productivity in mulberry by reducing irrigation requirement and enhancing nutrient availability in the root zone. In mulberry, hydrogel application has been reported to increase leaf yield and profitability despite a marginal increase in cultivation cost, owing to better moisture conservation and improved plant growth. The integration of fertigation with hydrogel application improves water and nutrient use efficiency by enhancing soil moisture retention and reducing nutrient losses in the root zone. While both fertigation and hydrogels individually enhance crop productivity, studies evaluating their combined effects on mulberry growth, leaf yield, economic returns and subsequent silkworm performance remain limited. In this background, the present study was undertaken to assess the impact of hydrogel application and graded levels of fertigation on profitability of mulberry leaf and cocoon production. The study aims to identify economically optimal fertigation levels and evaluate whether hydrogel application can reduce input costs and help earn enhanced returns, thereby providing a sustainable and profitable strategy for mulberrysericulture.

Materials and Methods

The experiment was conducted during 2025 in well-established V1 mulberry garden at L-block, Agroforestry based Integrated Farming System demo unit, University of Agricultural Sciences, Gandhi Krishi Vigyan Kendra, Bengaluru. The field is located at a latitude of 12°58' N and longitude of 77°35' east and at an altitude of 930 m above mean sea level in the Eastern Dry Zone (Zone 5) of Karnataka. The experiment was conducted with eight treatment combinations viz., T 1 -50% RDNK through fertigation T 2 -50% RDNK through fertigation + hydrogel ® @ 6 kg ac -1 T 3 -75% RDNK through fertigation T 4 -75% RDNK through fertigation + hydrogel ® @ 6 kg ac -1 T 5 -100% RDNK through fertigation T 6 -100% RDNK through fertigation + hydrogel ® @ 6 kg ac -1 T 7 -RDNK as per Package of Practice and T 8 -Control (RDF as per Package of Practice) Note: ® Starch-based Zeba hydrogel These treatments were laid out in RCBD design with three replications. Hydrogel application was carried out only once for first crop after the pruning (as used by Harshita Mala et al., 2023) [6] Fertigation (T 1 to T 6 ) application was carried out in three equal splits at weekly intervals (15 th to 29 th days after pruning) for both first and second crop (similar to those carried out by Mahesh et al., 2022) [10] , T 7 (without P for second crop) and T 8 (with P for both crops) were acted as control treatments. The fertilizers for T 7 and T 8 were applied at 20 days after pruning as per Dandin and Giridhar (2014) [5] . FYM @ 20 t ha -1 yr -1 was applied after pruning of mulberry and irrigation was given based on soil moisture content for all the treatments. N (Urea) and K (Muriate of potash) were applied through fertigation for both the crops. Phosphorus is immobile in soil, while is mainly responsible for root growth, so applied only once as basal dose for all the treatments except T 8 (Arunadevi and Selvaraj, 2013) [2] . Single point sensors were placed at 15 cm depth to ensure enough water for crop growth. Soil moisture indicator developed by Sugarcane Breeding Institute, Coimbatore was used which works on principle of resistance but, the depiction will be in the form of colour.

The treatment-wise cost of cultivation was worked out by considering the cost of all the labour and material inputs including the imputed values for land, depreciation of various machinery and equipment used in mulberry cultivation and cocoon production. The prices of the inputs that at the time of their use and value of the cocoons produced on the basis of prevailing market rates were considered.

The net returns per ha were calculated by deducting the total cost of cultivation (consisting of variable cost and fixed cost items) per hectare from gross returns realised per ha.

Benefit: Cost ratio: Benefit cost ratio was worked out by using following formula:

Benefit: Cost ratio= Gross returns/Cost of cultivation

Results and Discussion

The results and discussion on economics of mulberry cultivation and cocoon production under hydrogel and graded levels of fertigation are presented in the following sections:

# Inclusive of phosphorous application as basal dose

The total cost of mulberry cultivation under different treatments on a per hectare per crop basis by combining the base cultivation cost with treatment-specific inputs is presented in Table 3. The cost of cultivation excluding cost of treatment remained constant across all treatments (Rs. 47,325/-), representing the common operational and fixed costs of mulberry cultivation. Variations in total cost were mainly due to differences in fertilizer application rates and the inclusion of hydrogel. Fertilizer costs ranged from Rs. 2,695/-in T 1 and T 2 to Rs. 3,658/-in treatments receiving higher fertilizer levels. Treatments with hydrogel (T 2 , T 4 and T 6 ) resulted in an additional cost of Rs. 2,376/-, taking to higher total cost. Consequently, the total cost varied from Rs. 50,021/-(T 1 ) to a maximum of Rs. 53,360/-(T 6 ). Thus, results presented in table indicated that the inclusion of hydrogel and higher fertilizer doses increased production costs, while the baseline cost of cultivation remained unchanged. The fertilizer cost values included phosphorus applied as a basal dose. The cost of cocoon production from rearing 650 DFLs, consisted of both variable cost and fixed cost components. The total cost of cocoon production excluding the cost of Mulberry leaves was estimated at Rs. 40877/-, of which variable costs contributed for the major share (Rs. 39,615/-). Labour expenditure accounted for Rs. 8,650/-, with human labour forming the major component (Rs. 7,950/-), as expected the proportion of women labour (Rs. 6,750/-) exceeded men labour (Rs. 1,200/-). Machine labour cost was Rs. 700 towards disinfection of rearing house. Material costs were dominated by chawki worms, which accounted for the highest expenditure (Rs. 26,000/-), indicating that seed cost is the major cost driver in cocoon production.

Other supporting expenses included paraffin paper and accessories, disinfectants, marketing charges and electricity, together contributing a smaller share to the total. Interest on working capital at 10% added Rs. 314/-, increasing the operational cost. Fixed costs were minimal (Rs. 1,262/-) and mainly comprised depreciation on building and equipment along with interest on fixed capital. Overall, the table highlights that variable costs, particularly chawki worms and labour, constitute the major share of total cocoon production cost. fertigation level substantially improved profitability due to increased mulberry yield and cocoon production and economic efficiency compared to treatments without hydrogel or with suboptimal fertigation. The maximum economic returns with hydrogel and graded fertigation were due to improved soil moisture retention, nutrient use efficiency and higher mulberry yields. Hydrogels store water in the root zone and release it gradually, reducing water stress, enhancing leaf growth and biomass, and increasing productivity compared to treatments without hydrogel (Agbna et al., 2025) [1] . Although hydrogels add towards production cost, multiple studies on hydrogels have indicated that crop yield and savings in water and fertilizer use, respectively often outweigh these costs. For example, hydrogel application in wheat resulted in higher gross and net monetary returns and improved benefit-cost ratios compared to control treatments without hydrogel, demonstrating its positive economic impact through yield and water productivity gains (Waghmare et al., 2025) [15] . Another study in mulberry itself revealed that 100% RDNK + starchbased hydrogel @ 6 kg -1 resulted in maximum leaf yield (8116 kg ha -1 crop -1 ), water productivity (611.61 kg ha-cm -1 ) with saving 21.43% of water (Ranganatha et al., 2025) [12] , which all can suffice the usage of hydrogel though it is added expenditure in the production cost. The present study is in partial agreement with the findings of Harshitha Mala et al. (2024) [7] who revealed that the highest cultivation cost (Rs. 83,173/-ha ⁻¹ ) for pusa hydrogel @ 4 kg treated plots and the lowest cultivation cost (Rs. 77,245/-ha ⁻¹ ) for control plots, while net returns (Rs. 1,48,812/-ha ⁻¹ ) and B:C ratio (2.88) were highest in Zeba hydrogel @ 6 kg ac⁻¹, highlighting improved profitability with hydrogel in mulberry. Madhu et al. (2024) [9] reported the cost of cocoon production of small farmer per batch was Rs. 48,988/-with highest gross returns (63,240/-) and net returns (14,150/-). A study by Imamsaheb et al. (2011) [8] revealed that higher yield (63.78 t/ha) and net income (Rs.1,14,471/-ha ⁻¹ crop⁻¹), gross income (Rs.1,59,450/-ha ⁻¹ crop⁻¹) and B:C ratio (3.22) was observed in tomato genotypes when 100% recommended NPK fertilizers was applied through fertigation.

The study concludes that integrating hydrogel application with optimized fertigation significantly improve the profitability of mulberry leaf production and cocoon production. Application of 75% recommended dose of nitrogen and potassium through fertigation combined with hydrogel recorded the highest net returns and benefit-cost ratio, owing to improved soil moisture retention, enhanced nutrient use efficiency and higher productivity. Although hydrogel application slightly increases the cultivation cost, the additional expenditure was offset by good yields and profitability. Hence, the combined use of hydrogel and optimized fertigation emerged as a viable and sustainable strategy for enhancing resource-use efficiency and economic returns in mulberry sericulture.

References

1. Agbna GH, Shahab A, Zaidi SJ. Multifunctional hydrogel systems: integrating nutrient delivery, soil enhancement, and climate resilience in modern agriculture. Desalin Water Treat. 2025;101372.
2. Arunadevi K, Selvaraj PK. Moisture distribution and fertilizer mobility under drip fertigation in mulberry. J Soil Water Conserv. 2013;12(2):123-129.
3. Bandyopadhyay A, Ghosh DK, Biswas B, Parameswarappa MH, Timsina J. Fertigation effects on nutrient use efficiency, energy productivity, and economics of coconut (Cocos nucifera L.) cultivation in the eastern Indo-Gangetic Plains of South Asia. Int J Fruit Sci. 2020;20(Suppl 3):1483-1494.
4. Bongale UD, Chaluvachari, Mallikarjunappa RS, Narahari Rao BV, Anantharaman MN, Dandin SB. Leaf nutritive quality associated with maturity levels in fourteen important varieties of mulberry (Morus spp.). Sericologia. 1997;37(1):71-81.
5. Dandin SB, Giridhar K. Handbook of sericulture technologies. Bangalore: Central Silk Board; 2014. p. 427.
6. Harshita Mala P, Banuprakash KG, Hanumanthappa DC, Vinoda KS. Efficacy of hydrogels under sensor-based irrigation on growth and productivity of tree mulberry. Mysore J Agric Sci. 2023;57(4):135-144.
7. Harshita Mala P, Banuprakash KG, Vinoda KS. Economic impact of hydrogel application in cocoon production using sensor-based irrigation. Int J Environ Clim Change. 2024;14(9):159-163.
8. Imamsaheb SJ, Patil MG, Naik MK, Hussain Abbas S, Ayyangoudar MS. Yield, yield components and quality of processing tomato (Solanum lycopersicum L.) genotypes as influenced by different levels of fertigation. Environ Ecol. 2011;29(1):229-232.
9. Madhu DM, Sinha DK, Gowda H, Haripriya S, Kumari T. An economic analysis of mulberry silk production in Chikkaballapur district of Karnataka. Agric Res J. 2024;61(2):203-217.
10. Mahesh R, Anil P, Debashish C, Sivaprasad V. Improved mulberry productivity and resource efficiency through lowcost drip fertigation. Arch Agron Soil Sci. 2022;68(6):749763.
11. Neethu TM, Dubey PK, Kaswala AR. Prospects and applications of hydrogel technology in agriculture. Int J Curr Microbiol Appl Sci. 2018;7(5):3155-3162.
12. Ranganatha K, Hanumanthappa DC, Vinoda KS, Banuprakash KG, Nisarga K. Influence of hydrogel and graded levels of fertigation on growth and productivity of mulberry. Int J Res Agron. 2025;8(12):1130-1135.
13. Singh MK, Chowdhuri RS, Naqvi AH, Ghosh MK, Bindroo BB. Studies on integrated nutrient management on leaf yield and quality of silk of mulberry (Morus alba L.) grown under rainfed situation. J Crop Weed. 2012;8(2):80-82.
14. Thomas SL, Bindhu JS, Pillai SP, Beena R, Biju J, Sarada S. Nutrient dynamics and moisture distribution under drip irrigation system. J Exp Agric Int. 2024;46(10):485-493.
15. Waghmare SR, Patil PR, Surve US, Shendage GB, Sonwalkar TT, More NS. Effect of irrigation and hydrogel levels on yield and economics of wheat (Triticum aestivum L.). Int J Res Agron. 2025;8(8):459-463.