Influence of organic nutrient management practices on growth and quality attributes of sesame

Introduction

Organic agriculture is increasingly recognized as a sustainable farming approach that enhances soil health, promotes ecological balance, and ensures residue-free food. In India, the total area under organic certification reached 10.17 million hectares in 2023-24, of which 5.39 million ha is cultivable and 4.78 million ha is under wild harvest collection (APEDA, 2024) [1] . During this period, the country produced about 3.60 million MT of certified organic products, covering oilseeds, cereals, pulses, spices, fruits, vegetables, and plantation crops. Among these, oilseeds alone contributed nearly 47.6% of the export value, highlighting their significance in the organic sector (APEDA, 2024) [1] . Sesame (Sesamum indicum L.) is one of the oldest oilseed crops and is widely cultivated for its high-quality edible oil and multiple uses in food, medicine, and cosmetics. Globally, sesame is grown on 12.5 million ha with an annual production of 6.35 million tonnes and productivity of 515 kg ha -1 . India is a major player with 29.8% of global sesame area, 25.8% of production, and nearly 40% share in exports (INDIASTAT, 2024) [10] . Within India, sesame is cultivated on about 1.0 million ha, producing 0.82 million tonnes, with an average productivity of 450 kg ha -1 . Telangana is one of the leading states, cultivating 57,485 ha with an annual production of 1,48,310 tonnes and productivity of 714 kg ha -1 , particularly concentrated in northern districts such as Adilabad, Jagtial, Karimnagar, and Nizamabad (INDIASTAT, 2024) [10] . Sesame oil is rich in unsaturated fatty acids (85%), resistant to rancidity, and contains bioactive compounds with cholesterol-lowering and cardioprotective effects (Gopinath et al., 2011) [9] .

Its high oil content (46-49%), nutritional value, and export potential make sesame a crop of national and international importance. Despite its advantages, sesame production and exports are challenged by pesticide residues and the long-term negative effects of indiscriminate chemical fertilizer use, which include nutrient imbalance, soil health deterioration, and reduced inputuse efficiency (Kumar et al., 2010; Cai et al., 2016) [16,4] . Organic farming offers a sustainable solution by avoiding synthetic inputs and emphasizing the use of FYM, composts, enriched vermicompost, neem cake, humic acid, and biofertilizers to supply nutrients (Muthuswamy et al., 1990) [20] . Biofertilizers in particular enhance nutrient availability by fixing nitrogen, solubilizing phosphorus, and mobilizing potassium, while foliar organics like Panchagavya and vermiwash improve crop growth and quality. Balanced and prolonged nutrient supply from such inputs has been shown to enhance dry matter production, seed yield, protein content, and oil yield in oilseed crops (Parthasarathi et al, 2012; Dharati et al., 2017; Nirav Parmar et al., 2020) [24,6,22] . Considering the nutritional and export value of sesame, coupled with the rising global demand for organic produce, the present study was undertaken to evaluate the effect of organic nutrient management practices on plant growth parameters, protein yield, and oil yield of sesame under rainfed conditions.

Materials and Methods

Experimental site and climate

A field experiment was conducted during late kharif 2019 at the College Farm, Agricultural College, Polasa, Jagtial, Professor Jayashankar Telangana Agricultural University, Telangana. The site is located at 18º49′40″ N latitude, 78º56′45″ E longitude, at an altitude of 243.4 m above mean sea level, and falls under the Northern Zone of Telangana. During the crop period, the weekly mean maximum temperature ranged from 29.2-32.3°C (mean 31.2°C) and the minimum from 15.6-24.1°C (mean 21.1°C). The total rainfall was 465.1 mm received in 37 rainy days, with prolonged dry spells during the 45th-49th standard weeks. The mean sunshine duration was 6.4 h day -1 .

Soil and nutrient sources

Composite soil samples (0-30 cm) collected before sowing were analyzed for pH, EC, organic carbon, and available N, P, and K. The soil was sandy loam, neutral in reaction, low in available N, medium in P, and high in K. The nutrient contents of organic inputs were estimated as per Bradstreet (1965) [3] , and were 0.51, 0.17, and 0.43% for FYM; 1.16, 0.21, and 0.62% for vermicompost; 4.31, 0.63, and 1.26% for neem cake; and 1.21, 1.50, and 0.67% for enriched vermicompost, respectively.

Treatments and experimental design

The experiment was laid out in a Factorial RBD design with four main treatments of basal organic nutrient management and four sub treatments of foliar organics, replicated thrice. The main treatments included:  T1: 50% N through FYM + 25% N through vermicompost + 25% N through neem cake  T2: 50% N through FYM + 25% N through enriched vermicompost + microbial consortia @ 2 kg ha -1  T3: 50% N through FYM + 25% N through neem cake + humic acid granules @ 12.5 kg ha -1  T4: 75% N through FYM + 25% N through enriched vermicompost + microbial consortia @ 2 kg ha -1

The sub treatments consisted of foliar applications:  S1: Panchagavya @ 3%  S2: NSKE @ 3%  S3: Vermiwash @ 10 ml L -1  S4: Humic acid @ 1 ml L -1 FYM, neem cake, humic acid granules, and microbial consortia were applied as basal, while vermicompost and enriched vermicompost were top-dressed at 25 and 50 DAS. Foliar sprays were imposed at flowering, 52 DAS, and 59 DAS.

Crop details and management

Sesame variety JCS-1020, released from RARS, Jagtial in 2019, was used. It is a non-branched, multi-capsular, white-seeded variety with 46-49% oil content, resistant to powdery mildew, and has a crop duration of 100 days. The crop was sown at 30 cm spacing using a seed rate of 2.5 kg acre -1 . Gap filling was carried out at 10 DAS and thinning at 20 DAS. The gross plot size was 5.1 × 5.0 m 2 and net plot size 3.9 × 4.4 m 2 . Weeding was done manually at 25 and 45 DAS. Bacillus thuringiensis @ 2 g L -1 was applied at flowering to control lepidopteran pests, and Trichoderma viride @ 5 g L -1 was drenched at 60 DAS to manage sucking pests and foliar diseases. Two irrigations were given at pod filling stage due to extended dry spells, and the crop was harvested on 5th December 2019.

Observations recorded 1. Growth parameters:

Plant height, number of branches plant -1 , number of capsules plant -1 , leaf area index (LAI), and total dry matter production were recorded at 30, 60 DAS and at harvest. LAI was calculated using the formula of Watson (1952).

Protein content and yield:

Seed nitrogen content was estimated using the Kjeldahl method (Jackson, 1973). Protein content (%) was calculated as N × 6.25 and protein yield (kg ha -1 ) was obtained by multiplying seed protein content with seed yield.

the Soxhlet extraction method with petroleum ether as solvent (AOAC, 1995). Oil yield (kg ha -1 ) was calculated by multiplying oil content with seed yield.

Statistical analysis

Data were analyzed using analysis of variance (ANOVA) for Factorial RBD design as per Gomez and Gomez (1984). Treatment means were compared using the critical difference (CD) at 5% level of significance.

Results and Discussion

Plant Height

Effect of organic nutrient management practices on plant height of sesame at different growth stages is presented in Fig 1.

Significant differences were observed among main treatments at 25 and 50 DAS. T 4 (75% N through FYM + 25% N through vermicompost enriched with rock phosphate + microbial consortia @ 2 kg ha -1 ) recorded the tallest plants at all stages: 24.6 cm (25 DAS), 58.8 cm (50 DAS), 79.6 cm (75 DAS) and 82.0 cm (harvest). This may be attributed to enhanced nutrient availability through microbial consortia and organic sources, as reported by Piploda and Kumawat (2022) [26] and Sagar and Chandra (2004) [28] . At 25 DAS, T 4 was on par with T 2 (50% N through FYM + 25% N through vermicompost enriched with rock phosphate + microbial consortia), while at 50 DAS it was not significant with T 1 (50% N through FYM + 25% N through vermicompost + 25%

N through neem cake). However, at 75 DAS and harvest, differences among main treatments were non-significant. Among sub-treatments, variations in plant height were nonsignificant at 25, 75 DAS and harvest. Panchagavya @ 3% recorded highest plant height at all stages: 22.5 cm (25 DAS), 60.3 cm (50 DAS), 79.2 cm (75 DAS) and 82.9 cm (harvest), being on par with other foliar sprays at early stages and significantly superior at later stages. Similar findings were reported by El Naim et al. (2010) [8] , Veeral et al. (2019) [32] in sesame and Kandil (2015) [12] in horse gram. The interaction effect between main and sub-treatments on plant height at all stages was non-significant. , 2024 [30] ; Dharati et al., 2017) [6] . Among the sub-treatments, Panchagavya @ 3% (S 1 ) recorded maximum dry matter (47.7, 106.2, 161.8 and 181.8 g m -2 ) at successive stages, on par with humic acid @ 1 ml lit -1 . Vermiwash @ 10 ml lit -1 and NSKE @ 3% recorded comparatively lower values but were statistically similar. The interaction effect was significant, with T 4 S 1 recording the highest dry matter at 75 DAS (180.9 g m -2 ) and harvest (202.4 g m -2 ), which was at par with T 2 S 1 , T 4 S 2 , T 4 S 3 , T 4 S 4 , T 1 S 1 and T 1 S 4 . The results indicate that integrated application of enriched organic sources with foliar sprays effectively enhanced nutrient availability and biomass accumulation, as also reported by Duhoon et al. (2004) [7] in sesame and Parthasarathi and Sinha (2012) in groundnut.

Leaf area

Leaf area of sesame at different growth stages is presented in Fig. 3. At 25 DAS, leaf area was not significantly influenced by main or sub-treatments. However, significant differences were observed at 50 and 75 DAS. Among the main treatments, T 4 (75% N through FYM + 25% N through vermicompost enriched with rock phosphate + microbial consortia @ 2 kg ha -1 ) recorded the highest leaf area with 421.7 and 592.6 cm² plant -1 at 50 and 75 DAS, respectively, distinctly higher than other treatments. This was followed by T 2 (373.8 and 549.8 cm² plant -1 ) which remained significantly superior to T 1 and T 3 . At 50 DAS, T 3 (345.1) was on par with T 1 (341.4), but at 75 DAS, T 3 surpassed T 1 . The superiority of P-enriched vermicompost in T 4 and T 2 may be attributed to its higher nutrient quality and sustained release, as earlier reported by Sagar and Chandra, (2004) [28] . Among sub-treatments, differences were not evident at 25 DAS, but at 50 DAS Panchagavya @ 3% (S 1 ) recorded the maximum leaf area (495.1 cm² plant -1 ), followed by vermiwash (386.6), humic acid (362.2), and NSKE (338.1). At 75 DAS, vermiwash (S 3 ) produced the highest leaf area (564.3 cm² plant -1 ), followed by Panchagavya (542.0), humic acid (506.2) and NSKE (499.9), with S 2 and S 4 being statistically at par. The interaction effect was significant at 50 and 75 DAS. The combination T 4 S 3 recorded the maximum leaf area at both stages (564.0 and 784.8 cm 2 plant -1 ), followed by T 4 S 1 (546.0) and T 2 S 4 (515.6) at 50 DAS, while at 75 DAS it was followed by T 3 S 1 (757.4), T 4 S 4 (733.6) and T 4 S 1 (708.4). Lowest leaf area was observed in T 2 S 2 (412.3) at 50 DAS and T 1 S 2 (602.4) at 75 DAS. The beneficial effect of foliar organics, particularly humic acid and Panchagavya, in improving photosynthetic surface has been earlier reported by Ayoubizadeh et al. (2018) [2] , Khaled et al. (2012) [15] . Similarly, no significant differences were observed among subtreatments. Panchagavya @ 3% (S 1 ) recorded relatively higher values at 25 and 50 DAS (31.2 and 33.8), which may be due to enhanced availability of Fe, N, P and S promoting chlorophyll synthesis, as also reported by Tejada and Gonzalez (2003) [31] . At 75 DAS, humic acid @ 1 ml L⁻¹ (S 4 ) showed a comparatively higher value (33.6). The interaction effect between main and subtreatments was not significant at any stage.

Seed Yield

Seed yield of sesame as influenced by organic nutrient management practices is presented in Fig 5 . Main treatments and their interaction with foliar organic sources significantly affected yield, whereas the effect of foliar sources alone was nonsignificant. Among main treatments, application of 75% N through FYM + 25% N through vermicompost enriched with rock phosphate + microbial consortia @ 2 kg ha -1 (T 4 ) recorded the highest seed yield (478 kg ha -1 ), followed by T 2 (433 kg ha -1 ), which was at par with T 1 (424 kg ha -1 ) and T 3 (405 kg ha -1 ). The superior performance of vermicompost enriched with rock phosphate could be attributed to improved availability of P, K and S, leading to enhanced yield and quality, as also reported by Parthasarathi et al (2012) [24] . Although sub-treatments did not differ significantly, foliar application of organic sources enhanced sesame yield. Panchagavya @ 3% (450 kg ha -1 ) recorded the highest value, followed by humic acid, vermiwash and NSKE. The beneficial effect may be linked to the presence of nutrients, enzymes and growth regulators that improved yield and reduced pest incidence (Tejada and Gonzalez, 2003) [31] . The interaction effect was significant, with combined application of enriched manures and foliar sprays showing greater impact on seed yield.

Protein yield

Protein yield of sesame as influenced by organic nutrient management is presented in Table 1. Sesame is a rich source of 12-18% protein, vitamin B1, PUFA (palmitic and stearic acids), natural antioxidants, and lignans such as sesamin and sesamolin (Pathak et al., 2014 [25] ; Meena et al., 2018) [18] . Main treatments significantly affected protein yield, with T 4 (75% N through FYM + 25% N through vermicompost enriched with rock phosphate + microbial consortia @ 2 kg ha -1 ) recording the highest yield (68.92 kg ha -1 ). This was followed by T 2 (56.78 kg ha -1 ) and T 1 (52.99 kg ha -1 ), while the lowest was observed in T 3 (48.24 kg ha - 1 ). Higher protein yield under T 4 may be attributed to improved N and S availability through enriched vermicompost and microbial consortia, as also reported by Ramakrishna et al. (2017) [27] in groundnut and Duhoon et al. (2004) [7] in sesame. Foliar applications did not significantly influence protein yield. However, S 1: Panchagavya @ 3% recorded the highest protein yield (59.0 kg ha -1 ), followed by humic acid (56.57 kg ha -1 ). The enhanced protein accumulation could be linked to better nutrient mobilization and physiological stimulation by these organic inputs (Vishal Kumar et al., 2019) [33] . The interaction effect between main and sub treatments was not significant.

Oil yield

Oil yield of sesame as influenced by organic nutrient management is presented in Table 2. Main treatments and their interaction with sub treatments significantly affected oil yield, while foliar applications alone were non-significant. Among main treatments, T 4 (75% N through FYM + 25% N through vermicompost enriched with rock phosphate + microbial consortia @ 2 kg ha -1 ) recorded the highest oil yield (219.2 kg ha -1 ), followed by T 2 (194.9 kg ha -1 ) and T 1 (187.6 kg ha -1 ). The lowest yield was observed under T 3 (168.6 kg ha -1 ). The superiority of T 4 could be attributed to balanced nutrient availability from diversified organic sources that enhanced oil synthesis, as also supported by Keller and Bliesner (2000) [14] . Foliar applications recorded oil yields ranging from 188.3 to 199.8 kg ha -1 , with S 1: Panchagavya @ 3% (199.8 kg ha -1 ) being superior, followed by humic acid (192.3 kg ha -1 ). Positive effects of humic acid in enhancing physiological and biochemical traits have been reported in tomato (Yildrim, 2007) [34] and pepper (Karakurt et al., 2009) [13] . The interaction effect was significant, where T 4 S 1 (232.47 kg ha -1 ) recorded the highest oil yield, and was on par with T 4 S 2 , T 4 S 3 , T 4 S 4 , T 2 S 1 and T 2 S 2 . Oil yield (Kg ha -1 ) Main Treatments T1: 50% N through FYM + 25% N through vermicompost + 25% N through Neem cake 44.3 187.6 T2: 50% N through FYM + 25% N through vermicompost enriched with rock phosphate + microbial consortia @ 2 kg ha -1 45.0 194.9 T3: 50% N through FYM + 25% N through Neem cake + Humic acid granules @ 12.5 kg ha -1 41.6 168.6 T4: 75% N through FYM + 25% N through vermicompost enriched with rock phosphate + microbial consortia @ 2 kg ha -

Conclusion

The experiment demonstrated that organic nutrient management significantly improved sesame growth, yield, and quality attributes. Application of 75% N through FYM + 25% N through vermicompost enriched with rock phosphate + microbial consortia @ 2 kg ha -1 (T 4 ) recorded the highest plant height, dry matter accumulation, leaf area, seed and stalk yield, protein, and oil yield, followed by T₂. SPAD chlorophyll readings and harvest index were not significantly influenced. The superior performance of T₄ may be attributed to improved nutrient availability and microbial activity. Overall, the integrated use of organic nutrient sources enhanced sesame productivity, soil fertility, and environmental sustainability, indicating its suitability for organic and eco-friendly sesame cultivation.

Future scope

Application of organic sources helps to maintain sustainability and higher profitability in sesame by saving the cost of production.

Acknowledgement

Acknowledgements:The financial support received from Professor Jayashankar Telangana Agricultural University is duly acknowledged. Authors also acknowledge their sincere thanks to Farm Incharge, Department of Agronomy and PG Incharge, Agricultural College, Jagtial for providing the experimental site at their farm as well as logistical support.

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