Growth, nutrient uptake and soil nutrient status of sesame (Sesamum indicum L.) as influenced by levels and sources of soil applied sulphur in a Vertisol

Introduction

Sesame (Sesamum indicum L.), often called the queen of oilseeds, is one of the oldest oilseed crops and its oil is unusually stable against oxidation because of lignans such as sesamin and sesamol. India has the largest area under sesame in the world, 15.31 lakh hectares in 2023-24, but productivity is only 553 kg ha -1 , which is attributed to rainfed cultivation, poor soil fertility and inadequate nutrient management (DES, 2024) [1] . Sulphur is the fourth major plant nutrient after N, P and K and is part of cysteine, methionine, proteins, enzymes and chlorophyll. Oilseeds need more of it than cereals and a shortage reduces growth, branching, capsule formation and seed and oil yield (Scherer, 2001). Sulphur deficiency has become widespread in Indian soils, with about 59 per cent of the samples in a national assessment falling in the deficient class (Shukla et al., 2021). Intensive cropping, removal of crop residues and increasing use of sulphur-free fertilizers such as urea and DAP are the main reasons. Deficiency also lowers nitrogen-use efficiency because nitrogen assimilation depends on sulphur. Vertisols are deep, clay-rich soils of peninsular India. They are generally fertile but can be low in available sulphur where organic carbon is low and fertilization is imbalanced (Gaikwad et al., 2021; Tandon, 2011) [2,3] . Sulphur sources differ in concentration, solubility and speed of release: gypsum supplies sulphate directly, whereas elemental sulphur has to be oxidised by soil microorganisms before the crop can use it. Location-specific recommendations on the rate and source of sulphur for sesame on Vertisols are still inadequate. The present investigation entitled "Performance of sesame (Sesamum indicum L.) as influenced by soil application of sulphur in a Vertisol" was therefore undertaken and this paper reports its effect on growth, nutrient uptake and soil nutrient status. ), available nitrogen (265.32 kg ha -1 ), available sulphur (9.80 mg kg -1 ) and DTPA-zinc (0.36 mg kg -1 ), with medium available phosphorus (35.23 kg P 2 O 5 ha -1 ) and potassium (369.25 kg K 2 O ha -1 ). Maize was the preceding crop. The experiment was laid out in a split-plot design with three replications. The main plots carried three sulphur levels (S 1: 10, S 2: 15 and S 3: 20 kg S ha -1 ) and the sub plots carried three sources (F 1: bentonite sulphur, F 2: gypsum and F 3: elemental sulphur), giving nine treatment combinations. Sulphur was applied basally and incorporated before sowing. Sesame variety Swetha was sown at 30 × 15 cm spacing in gross plots of 5.4 × 3.6 m. Farmyard manure at 5 t ha -1 and the recommended fertilizers at 50:20:20 kg N:P 2 O 5 :K 2 O ha -1 were applied uniformly to all plots, and other agronomic and plant protection practices were followed as recommended. Five plants were tagged in each net plot and growth parameters were recorded at key stages of the crop. Soil and plant samples were analysed for physico-chemical properties and nutrient content using standard protocols, and nutrient uptake was worked out from nutrient concentration and seed and stalk yield. Data were subjected to ANOVA as per Panse et al. (1967) [4] , and treatment means were compared at 5 per cent critical difference (CD).

Material and methods

A field experiment was conducted during

Results and discussion

Plant height, number of branches, leaf area plant -1 and leaf area index increased with each increment of sulphur throughout the crop period and the differences among the three levels were significant at 60 DAS and at harvest (Table 1). At harvest, 20 kg S ha -1 (S 3 ) recorded a plant height of 94.18 cm, 5.83 branches plant -1 , a leaf area of 11.23 dm 2 plant -1 and a leaf area index of 2.00, against 85.56 cm, 4.67, 8.80 dm 2 and 1.60 at 10 kg S ha -1 (S 1 ). Leaf area peaked at 60 DAS (22.17 dm 2 plant -1 under S 3 ) and declined towards harvest as the leaves senesced. The better growth at higher sulphur levels can be attributed to the role of sulphur in chlorophyll formation, protein synthesis and enzyme activity, which support cell division, leaf expansion and the development of lateral shoots. The present findings are in agreement with Kumari Priya and Debbarma (2025) [5] , Kumawat et al. (2025) [6] and Karanam Navya Jyothi et al. (2025) [7] . Sulphur source also had a significant effect. Bentonite sulphur (F 1 ) recorded the taller plants (93.94 cm), the most branches (5.73 plant -1 ) and the higher leaf area (11.00 dm 2 plant -1 ) and leaf area index (1.93) at harvest, whereas gypsum (F 2 ) recorded the lower values (87.03 cm, 4.60, 8.93 dm 2 and 1.67, respectively), with elemental sulphur in between; only plant height under elemental sulphur and gypsum was on par at harvest. The superior growth under bentonite sulphur may be attributed to a more sustained release of sulphur over the crop period, whereas gypsum supplies sulphate that is available early but can run short by the time of peak demand. Similar superiority of bentonite sulphur over gypsum in sesame was reported by Karanam Navya Jyothi et al. (2025) [7] and Ramakrishna (2013) [8] . The interaction was non-significant for all growth parameters, although S 3 F 1 recorded the numerically higher values at harvest (96.80 cm, 6.30 branches, 12.40 dm 2 and 2.20, respectively). Nutrient concentration in seed and stalk and total uptake of N, P, K and S increased significantly with each increase in sulphur level (Table 2). Total uptake at 20 kg S ha -1 was 78.56, 14.41, 71.88 and 16.04 kg ha -1 of N, P, K and S, compared with 50.43, 8.98, 42.76 and 10.20 kg ha -1 at 10 kg S ha -1 . Nitrogen showed the larger response. Seed nitrogen rose from 3.35 to 3.97 per cent and total N uptake rose by 28.13 kg ha -1 while S uptake rose by 5.84 kg ha -1 . This points to the close link between the two nutrients, since cysteine and methionine are needed to convert absorbed nitrogen into protein. Part of the increase in uptake also came from the larger seed and stalk yields under higher sulphur (Table 2). Similar increases in nutrient uptake with sulphur were reported by Niharika et al. (2025) [9] and Yadav et al. (2025) [10] and Jhansi et al. (2024) [11] likewise recorded higher phosphorus uptake. Bentonite sulphur recorded the higher total uptake of N, P, K and S (71.38, 13.60, 67.67 and 15.32 kg ha -1

), followed by elemental sul-phur (64.62, 11.85, 56.68 and 12.98 kg ha -1 ) and gypsum (56.59, 9.68, 46.90 and 10.85 kg ha -1 ) and the three sources differed significantly for all four nutrients. Both higher concentration in seed and stalk and larger biomass contributed to this and the result is consistent with the slower release of sulphur from bentonite. Kumar et al. (2018) [12] reported higher sulphur content and uptake with bentonite sulphur than with gypsum in mustard and Prusty et al. (2024) [13] found that the source of sulphur influenced nutrient uptake in sesame. The interaction was non-significant and S₃F₁ recorded the numerically higher total uptake of N, P, K and S (87.29, 16.40, 83.34 and 18.50 kg ha -1 ). Soil pH (8.12-8.19), EC (2.13-2.18 dS m -1

) and organic carbon (3.37-3.45 g kg -1 ) after harvest were not significantly affected by sulphur level, source or their interaction, which can be explained by the buffering capacity of the clay soil and the small quantity of sulphur applied in a single season. Available N, P 2 O 5 and K 2 O increased with sulphur level (Table 3). Twenty kg S ha -1 recorded 258.60, 35.80 and 359.67 kg ha -1 , significantly more than 15 kg S ha -1 (250.60, 34.43 and 346.00 kg ha -1 ), which was on par with 10 kg S ha -1 . Sources did not differ significantly in available N and K and bentonite sulphur (35.90 kg P 2 O 5 ha -1

) exceeded gypsum (33.40 kg P 2 O 5 ha -1 ) only for phosphorus. The gain at higher sulphur may be linked to better root growth, greater residue returns and nutrient cycling and similar improvements in soil nutrient availability with sulphur were reported by Bhardwaj et al. (2025) [14] and Khandare et al. (2024) [15] . Available sulphur after harvest increased significantly at each level, from 11.73 mg kg -1 at 10 kg S ha -1 to 13.13 and 15.37 mg kg -1 at 15 and 20 kg S ha -1 and it was higher under bentonite sulphur (14.47 mg kg -1 ) compared with elemental sulphur (13.13 mg kg -1 ) and gypsum (12.63 mg kg -1 ), the last two being on par. All the treatments, including S 1 F 2 (10.80 mg kg -1 ), finished above the initial 9.80 mg kg -1 , which may benefit the following crop. Raja et al. (2007) [16] also reported higher post-harvest available sulphur at higher rates of application. DTPA-extractable Zn, Mn and Cu increased significantly with sulphur level and were highest under bentonite sulphur (0.76, 10.49 and 1.03 mg kg -1 , respectively), whereas Fe was not affected. Since bulk soil pH did not change, the increase may be related to changes in soil nutrient dynamics and greater root activity under adequate sulphur supply. Mohanty et al. (2019) [17] reported higher DTPA-Zn with sulphur application. The interaction was non-significant for all soil parameters, with S 3 F 1 recording the numerically highest available N, P 2 O 5 , K 2 O and S (265.20, 38.10, 364.40 kg ha -1 and 16.40 mg kg -1 ).

Conclusion

Soil application of sulphur improved growth, nutrient uptake and post-harvest available nutrient status of sesame on a sulphur-deficient Vertisol. Growth and total uptake of N, P, K and S increased significantly up to 20 kg S ha -1 , the highest level tested, and bentonite sulphur was superior to elemental sulphur and gypsum for most of the parameters studied. Soil pH, EC and organic carbon were not affected. The interaction was non-significant, so the effects of level and source were additive, and 20 kg S ha⁻¹ through bentonite sulphur (S₃F₁) recorded the numerically highest values. Because the response had not levelled off at 20 kg S ha⁻¹, higher rates deserve testing over more seasons and locations.

tions throughout the investigation and in the preparation of this manuscript. ; S 3: 20 kg S ha -1 . F 1: bentonite sulphur; F 2: gypsum; F 3: elemental sulphur. Sulphur was applied basally and incorporated before sowing. DAS: days after sowing; NS: non-significant. Plant height and branches at 90 DAS were the same as at harvest. ; S 3: 20 kg S ha -1 . F 1: bentonite sulphur; F 2: gypsum; F 3: elemental sulphur. Sulphur was applied basally and incorporated before sowing. NS: non-significant. Uptake was computed from nutrient concentration in seed and stalk and the respective yields. NS: non-significant. Soil pH, EC, organic carbon and DTPA-Fe were not significantly influenced by any treatment. Initial available S was 9.80 mg kg -1 .

Acknowledgement

AcknowledgementThis research was a part of M.Sc. thesis and the author greatly appreciates the research facilities and support provided by the College of Agriculture, Raichur, for conducting this study. The author is grateful to the members of the advisory committee, Major advisor Dr. Ravi S, Senior Soil Scientist, ICAR-KVK, Hagari and members Dr. M V Ravi, Professor, soil science and Extension leader, AEEC, Koppal, Dr. Manjunatha Bhanuvally, Associate Professor, Soil science, AEEC, Huvina Hadagali and Dr. Krishnamurthy D, Senior Scientist (Agronomy), AICRP, ICAR-KVK, Hagari, for their invaluable guidance, constant encouragement, kind support and constructive sugges

References

1. DES. Area, production and productivity of principal crops in India. New Delhi: Directorate of Economics and Statistics, Ministry of Agriculture and Farmers Welfare, Government of India; 2024.
2. Gaikwad SS, Prasad J, Ray SK, Srivastava R. Characteristics, mineralogy and spectral properties of some typical Vertisols of Vidarbha, Maharashtra, India. J Indian Soc Soil Sci. 2021;68(4):367-384.
3. Tandon HLS. Sulphur in soils, crops and fertilizers. New Delhi: Fertiliser Development and Consultation Organisation; 2011.
4. Panse VG, Sukhatme PV. Statistical methods for agricultural workers. 2nd ed. New Delhi: Indian Council of Agricultural Research; 1967.
5. Kumari Priya, Debbarma V. Effect of sulphur and micronutrients on growth and yield of sesame (Sesamum indicum L.). Int J Res Agron. 2025;8(6):328-332.
6. Kumawat RN, Yadav BL, Sharma BM. Response of sesame to sulphur and zinc fertilization under rainfed conditions. J Oilseeds Res. 2025;42(1):34-39.
7. Karanam Navya Jyothi, Bharathi D, Sabitha N, Maheswar Reddy P, Naga Madhuri KV. Effect of sources and levels of sulphur on growth and yield of sesame (Sesamum indicum L.) under southern agro-climatic zone of Andhra Pradesh. Int J Res Agron. 2025;8(2S):38-41.
8. Ramakrishna B. Growth and yield of sesame (Sesamum indicum L.) as influenced by sources and levels of sulphur. M.Sc. (Ag.) Thesis. Univ Agric Sci, Dharwad (India); 2013.
9. Niharika P, Saravana Pandian PP, Indirani R, Kumutha K. Effect of sulphur fertilization on soil adsorption-desorption dynamics, nutrient uptake and yield of sesame in Typic Chromustert. Plant Sci Today. 2025;12(3):1-10.
10. Yadav S, Yadav SS, Choudhary S, Dhakar D, Yadav LR, Kumar A. Optimizing sesame (Sesamum indicum L.) productivity and quality through integrated nitrogen and sulphur management under semi-arid conditions of Rajasthan, India. Int J Plant Soil Sci. 2025;37(2):122-132.
11. Jhansi AN, Srijaya T, Madhavi A, Spandana Bhatt P. Influence of phosphorus and sulphur application on nutrient content and uptake by sesamum in high phosphorus soils of Telangana. AATCC Rev. 2024;12(4):661-673.
12. Kumar V, Tyagi S, Paul SC, Dubey SK, Suman S. Effect of sources and doses of sulphur on S uptake and yield of mustard (Brassica juncea L.). Int J Curr Microbiol Appl Sci. 2018;7(1):5042-5047.
13. Prusty M, Alim MA, Swain D, Sahoo G, Ray M. Effect of different sources and levels of sulphur in sesame on yield, nutrient uptake and soil fertility in acid Alfisols of Odisha, India. Int J Plant Soil Sci. 2024;36(6):669-677.
14. Bhardwaj R, Yadav IR, Shekhawat AS, Dhayal LS, Saini DK, Shivran H, Bundela M. Integrated use of organic manures and sulphur for improving soil fertility, yield and economics of sesame (Sesamum indicum L.) under semi-arid conditions. Int J Plant Soil Sci. 2025;37(11):12-18.
15. Khandare R, Shirale S, Gajbhiye B, Yerma S. Different fractions of sulphur, their correlations with soil properties and yield of soybean and safflower influenced by long term fertilizers experiment under Vertisol. Asian J Soil Sci Plant Nutr. 2024;10(1):88-100.
16. Raja A, Hattab KO, Gurusamy L, Suganya S. Sulphur levels on nutrient uptake and yield of sesame varieties and nutrient availability. Int J Soil Sci. 2007;5(1):278-285.
17. Mohanty SK, Dash MK, Nayak RK. Influence of sulphur and zinc foliar spray on sesame (Sesamum indicum L.) in upland conditions. Int J Chem Stud. 2019;7(2):438-441.