Optimizing Sunflower Yield in Heavy Textured Soils Using Nano-enabled Nitrogen and Sulphur Fertilization

Aims: To assess the impact of nano-fertilization of nitrogen and sulphur on the growth, yield attributes, productivity, quality, nutrient uptake, post harvest soil nutrient status and economics of sunflower grown in clay loam soil. Study Design: Randomized block design. Place and Duration of Study: The field experiments were conducted during the kharif (July – October, 2024) and rabi (January - April, 2025) seasons at the Experimental Farm, Department of Agronomy, Faculty of Agriculture, Annamalai University, Annamalai Nagar. Methodology: The experimental methodology employed was randomized block design incorporating eleven treatment combinations, with three replications. The treatments comprised different combinations of nitrogen (30, 45, 60 and 90 kg ha-1) application through urea and nano urea and sulphur (45 kg ha-1) application through gypsum. Results: Among the treatments imposed, T11 (45 kg N ha-1 through urea + 45 kg N ha-1 through nano urea + 45 kg S ha-1 through gypsum) recorded the highest growth and yield attributes, seed yield (2722 kg ha-1) and stalk yield (4828 kg ha-1) and quality parameters in both crop seasons. This treatment also showed significantly greater uptake of N, P, K, and S by the crop in both crop seasons. With respect to soil nutrient status after harvest, T5 recorded the highest available nitrogen, T3 showed the maximum available phosphorus and potassium, while the highest available sulphur was observed in T8 in both crop seasons. With regard to economic returns, T11 recorded the highest net return and benefit cost ratio in both crop seasons. Conclusion: The findings indicate that integrated application of conventional and nano-fertilized nitrogen, along with sulphur, enhances sunflower performance and improves nutrient uptake and soil fertility under heavy textured soils.