Integrated nutrient management for enhancing growth and yield of Lentil (Lens culinaris Medik.)

Introduction

Lentil (Lens culinaris Medik.) is a key cool-season pulse in India, providing 22-28% protein and essential micronutrients while supporting cereal-pulse rotations through biological nitrogen fixation and soil fertility enhancement [1] . Globally, Canada is the largest lentil producer, followed by India and Australia, with India ranking high in sown area and consumption due to dietary patterns and policy support for pulses [2] . Syntheses place India's lentil production around 1.5-1.6 million tonnes on approximately 1.4-1.5 million hectares in recent years, reflecting gradual gains from improved varieties and management, though average yields remain below top-exporting countries due to abiotic and nutrient constraints [1,3] . Global overviews show India contributes roughly a quarter of world lentil area and near onefifth of production, while Canada's higher per-hectare productivity (often ≥1.3 t ha⁻¹) underpins its leading output and export share [2] . Within India, institutional notes report lentil output fluctuating near 1.3-1.6 million tonnes depending on seasonal rainfall and temperature, with productivity advances linked to timely sowing, phosphorus and zinc nutrition, and shortduration, disease-tolerant cultivars [1] . National compilations attribute the largest state contributions to Uttar Pradesh and Madhya Pradesh, together accounting for roughly two-thirds of national lentil production, followed by West Bengal and Bihar at about one-tenth each, with additional shares from Jharkhand, Rajasthan, Assam, and Uttarakhand [4,5] . Rajasthan's share is smaller in the all-India lentil landscape (commonly 1-3%), yet the crop has strategic importance in suitable districts under limited irrigation and residual moisture, contributing to diversification and soil health in pulsebased rotations [5] .

The southeast region of Rajasthan features light-to mediumtextured soils (Inceptisols/Alfisols) and moisture-limited rabi conditions, where erratic winter rainfall, terminal heat, and low inherent fertility constrain lentil productivity, intensifying the need for integrated nutrient management [6] . Regional planning documents highlight imbalances in macronutrients and widespread micronutrient deficiencies, notably zinc and occasional boron, which depress nodulation, biomass accumulation, pod set, and seed size in pulses [4] . Lentil (Lens culinaris Medik.) is a cool-season, self-pollinated pulse valued for short cooking time, affordability, and suitability in cereal-pulse rotations due to biological nitrogen fixation that improves soil fertility [7] . It is recognized as a nutrient-dense legume rich in protein, complex carbohydrates, dietary fiber, and folate, contributing significantly to dietary quality in vegetarian populations and food-insecure regions [8] . Beyond macronutrients, lentils contain bioactive compounds such as polyphenols, saponins, and phytosterols associated with antioxidant, antidiabetic, cardioprotective, and antiinflammatory activities, supporting their positioning as a functional food [9,10] . Lentil seeds typically provide about 20-30% protein, with favorable amino acid profiles for plant-based diets, alongside prebiotic carbohydrates and minerals including iron and zinc that address micronutrient deficiencies in vulnerable populations [11, 12] . Reviews highlight that lentils are rich in fiber and folates, and their polyphenols and phytosterols are linked to improved glycemic control, lipid metabolism, and reduced risk of chronic diseases when included regularly in diets [8,9] . Breeding and biofortification programs have released high-iron and high-zinc lentil cultivars across South Asia, enhancing the crop's role in combating hidden hunger while maintaining agronomic adaptation to local environments [7,12] . Given lentil's high protein and mineral density, balanced phosphorus and zinc nutrition is critical for nodulation, root growth, pod set, and seed filling that underpin both yield and grain nutrient quality in semi-arid and sub-humid ecologies like southeast Rajasthan [7,12] . Integrating organics (e.g., FYM/vermicompost), biofertilizers (Rhizobium, PSB), and calibrated fertilizers enhances nutrient-use efficiency and soil biological activity, improving productivity and sustaining the nutritive quality advantages that make lentil a strategic crop for household nutrition and market demand [7,8] . FYM, vermicompost, Rhizobium, and PSB work complementarily to raise lentil performance by improving soil health, nutrient availability, and biological N and P supply in moisture-limited rabi systems of southeast Rajasthan, thereby enhancing nodulation, canopy development, pods per plant, seed filling, yield, and profitability [1,4,6] . FYM increases soil organic carbon, aggregation, infiltration, and cation-exchange capacity while providing slow-release macro-and micronutrients, which stabilizes establishment and supports higher nutrient-use efficiency when combined with recommended fertilizers in pulses including lentil [4] . Vermicompost supplies readily mineralizable N, P, S, humic substances, and beneficial microbes that stimulate root growth and P uptake; Indian field studies show significant gains in lentil growth, yield, and economics when 5-6.5 t ha⁻¹ vermicompost is paired with Rhizobium or PGPR compared with fertilizer-only controls [13,14] . Lentil-specific Rhizobium (R. leguminosarum bv. viciae) inoculation increases nodulation, biomass, and seed yield by fixing atmospheric nitrogen, with co-inoculation alongside PSB or PGPR outperforming single inoculations in multi-location field work [15,16] . PSB mobilize sparingly soluble phosphates common in neutral-alkaline soils, raising plant-available P and improving branches, pods per plant, test weight, and seed yield; factorial trials document that Rhizobium + PSB plus adequate P consistently elevates P uptake and yield over either inoculant alone [17,18] . Consequently, integrated modules that combine FYM or vermicompost with Rhizobium + PSB and soil-testbased fertilizers (notably P and S, with Zn as needed) are recommended by national pulse programs to close the lentil yield gap, improve benefit:cost ratios, and build soil fertility across pulse-based rotations in the region [1,6] . Integrated Nutrient Management (INM)-the calibrated combination of organic manures, biofertilizers, and mineral fertilizers-improves soil structure, microbial activity, nutrient availability, and water-holding capacity, thereby enhancing lentil growth, nodulation, and yield under moisture variability typical of southeast Rajasthan [4] . Organics such as FYM and vermicompost increase soil organic carbon and cation exchange capacity, while Rhizobium and phosphorus-solubilizing bacteria (PSB) improve biological nitrogen fixation and phosphorus availability, complementing starter mineral N and band-placed P for early vigor and reproductive success [1] .

Materials and Methods

The field experiment on the effect of integrated nutrients management on the growth and yield of lentil was conducted at the Agriculture Research Farm, CPU, Kota (Rajasthan) during the Rabi season of 2025-26. The site is located at 25° 11' N latitude and 75° 54' E longitude with an elevation of 273 meters in the Humid South Eastern Plain Zone. The experimental soil was clay-loam in texture with an alkaline pH of 8.35, low organic carbon (0.42%), low available N (177 kg ha⁻¹), medium available P (14.6 kg ha⁻¹), and high available K (321 kg ha⁻¹). Nine treatments, including 100% RDF, various combinations of 75% and 50% RDF with FYM, vermicompost, Rhizobium, and PSB, along with a 100% organic module and a control, were tested in a Randomized Block Design with 3 replications. The lentil variety Kota Masoor-4 was sown on December 15, 2025, using a seed rate of 40 kg ha⁻¹ in rows spaced 30 cm apart. Recommended basal doses of fertilizers (20 kg N, 40 kg P2O5, and 20 kg K2O ha⁻¹) were applied along with required organics and biofertilizers. The crop relied on rainfall without supplemental irrigation and was harvested at full maturity on February 14, 2026.

Growth and Development Studies

Five average plants from each plot were randomly selected and tagged to record plant height from the soil surface base to the tip of the main apical bud at various physiological stages. The same tagged plants were utilized to count the number of branches per plant. Dry matter accumulation per plant was determined by sun-drying and subsequently oven-drying samples at 60±2°C until a constant weight was achieved. Additionally, the plant population per meter row length and the Leaf Area Index (LAI) at 45 days after sowing were also recorded to evaluate crop growth.

Yield Studies

To study yield attributes, pods picked from five randomly selected plants per plot were threshed and winnowed to determine the average number of pods per plant and seeds per pod. The weight of 100 seeds (seed index) was recorded from representative plot samples using an electronic balance. Biological yield was measured by weighing the completely sundried bundles of harvestable biomass for each plot. After manual threshing and cleaning, the final seed yield was recorded and converted into kg ha⁻¹. The straw yield was then computed by subtracting the seed yield from the biological yield.

Statistical Analysis

The data obtained from the experiment were subjected to analysis of variance (ANOVA) using the SPSS technique to define the statistical significance of the treatment effects. The significance of these effects was judged at a 5% probability level utilizing Fisher's 'F' test. Furthermore, the critical difference (CD) was calculated to examine and compare the significant differences between the various treatments.

Results and Discussion

The data on mean plant population revealed non-significant differences across all nutrient management treatments at both 30 DAS and maturity stages. The highest plant population was registered under treatment T 7 (50% RDF + Vermicompost @ 2 t ha⁻¹ + Rhizobium + PSB) with 21.25 plants at 30 DAS and 20.65 plants at maturity. The lowest plant population was recorded in the control plot, with 19.15 and 18.45 plants at the respective stages. The lack of statistical significance suggests that initial establishment is primarily governed by seed viability and physical seedbed conditions rather than fertilizer application.

Plant height grew steadily as the crop progressed toward maturity. At 30 DAS, differences were non-significant, with heights ranging from 9.85 to 13.40 cm. However, at 60 DAS and at harvest, plant height was significantly influenced by integrated nutrient management. The maximum plant height at 60 DAS (35.50 cm) and at harvest (51.20 cm) was recorded under T 7 , which remained statistically at par with T 6 (50% RDF + FYM @ 5 t ha⁻¹ + Rhizobium + PSB). The control plot produced the shortest plants (33.10 cm at harvest). Vermicompost, also known as FYM, is a storehouse of plant nutrients that may have enhanced the physicochemical and biological qualities of the soil, hence enhancing crop development similar finding found by Singh et al. [19,20] .

Number of Branches per Plant

All treatments significantly influenced the number of branches per plant at 30 DAS, 60 DAS, and maturity. At 30 DAS, the maximum number of branches (4.75) was observed in T 7 , which was at par with treatments T 1 through T 6 . At maturity, T 7 maintained the highest count (5.45), remaining statistically at par with all treated plots except the 100% Organic treatment (T 8 ). The control recorded the fewest branches (3.30). FYM or vermicompost stores plant nutrients that may have enhanced soil physico-chemical and biological qualities to boost crop development. However, soils fertilised only with chemical fertilisers lack all these advantages needed to accumulate carbohydrates and translocate them to reproductive organs, increase branch number [13,20] .

Dry weight increased considerably across all growth phases. The maximum dry weight at 30 DAS (0.30 g), 60 DAS (1.84 g), and maturity (2.25 g) was observed under T 7 , which was statistically at par with T 6 at all stages. The control resulted in the lowest dry weight at maturity (0.60 g). The significant enhancement in growth parameters under integrated treatments is attributed to organic sources like FYM or vermicompost acting as a storehouse of plant nutrients. These sources improve the physicochemical and biological properties of the soil, facilitating better accumulation of carbohydrates and their translocation to the plant organs. This results in increased height, branching, and biomass compared to plots receiving only chemical fertilizers. These findings are supported by the work of [19,21] .

Grain yield per hectare increased significantly with the application of integrated nutrients compared to the control. The application of T 7 (1025 kg) produced the maximum grain yield, which was statistically at par with T 6 (995 kg). Other treatments, including T 5 , T 4 , T 3 , T 2 , T 1 , and T 8 , also produced significantly higher grain yields over the control (490 kg). The control group had the lowest harvest index (35.38%). Organic sources such as FYM and vermicompost act as a reservoir of plant nutrients, improving the soil's physicochemical and biological properties. Unlike soils fertilised exclusively with chemical fertilisers, integrated treatments create the conditions for higher development of functional leaves as well as increased protein and carbohydrate storage. The synergistic action of organics and biofertilizers guarantees that these nutrients are effectively transported to the reproductive organs, resulting in an increase in pods per plant, seed weight, and total grain production. These findings are congruent with those of [23,24] .

All treatments were found significantly superior to the control in terms of straw yield. The highest straw yield was observed in T 7 (1615 kg), which was statistically at par with T 6 (1580 kg) and T 5 (1510 kg). The lowest straw yield was recorded in the control plot (895 kg). Organic sources like FYM and vermicompost retain plant nutrients that improve soil physicochemical and biological properties. In contrast to chemically fertilised soils, integrated treatments promote leaf formation and protein and carbohydrate accumulation. The synergy of organics and biofertilizers effectively translocates nutrients to reproductive organs, increasing pods per plant, seed weight, and grain output. These findings are consistent with [22,23] .

The highest biological yield per hectare was observed in T 7 (2640 kg), which was statistically at par with T 6 (2575 kg). All other integrated modules produced significantly higher biological yields compared to the control (1385 kg). Organic sources such as FYM and vermicompost act as a repository for plant nutrients, which in turn improves the physicochemical and biological characteristics of the soil. Integrated treatments, as opposed to soils that are just fertilised with chemical fertilisers, create the circumstances that are essential for the enhanced generation of leaves that are able to function and for the larger accumulation of proteins and carbohydrates. Because of the synergistic action of organics and biofertilizers, the effective transfer of these nutrients to the reproductive organs is ensured. This results in an increase in the number of pods produced by each plant, the weight of the seeds, and the volume of grain produced overall. These findings are in agreement with the findings of other researchers, such as [21,24] .

The maximum harvest index was observed in T 7 (38.83%), followed closely by T 6 (38.64%), T 5 (38.62%), and T 4 (38.51%). The lowest harvest index was recorded in the control (35.38%). Organic sources like FYM and vermicompost serve as a storehouse of plant nutrients that improve the soil's physicochemical and biological qualities. Unlike soils fertilized solely with chemical fertilizers, integrated treatments provide the necessary conditions for the increased production of functioning leaves and greater accumulation of proteins and carbohydrates. The synergistic effect of organics and biofertilizers ensures the effective translocation of these nutrients to the reproductive organs, leading to an increase in pods per plant, seed weight, and overall grain yield. These results are consistent with the findings of [19,21,23,24,25] .

Conclusion

Integrated nutrient management significantly improved the growth and yield of lentil (Lens culinaris Medik.) under southeastern Rajasthan conditions. The treatment 50% RDF + Vermicompost @ 2 t ha⁻¹ + Rhizobium + PSB (T 7 ) recorded the highest productivity and remained at par with 50% RDF + FYM @ 5 t ha⁻¹ + Rhizobium + PSB (T 6 ). Hence, combining organic manures and biofertilizers with reduced chemical fertilizers is an effective and sustainable approach for enhancing lentil yield and soil health.

Acknowledgement

AcknowledgementThe researchers express their gratitude to the Agronomy, School of Agricultural Sciences, Career Point University, Kota (Rajasthan), located in Kota-325003, for providing their facilities.

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