Studies on effect of sulphur oxidizing microorganism and humic acid on growth and yield of sunflower (Helianthus annus L.)

A field experiment was conducted in the kharif season of 2024-25 at the Department of Soil Science, College of Agriculture, Badnapur to study the effect of sulphur oxidizing microorganism and humic acid on growth and yield of sunflower (Helianthus annus L.). The experiment was laid out in a Randomized Block Design with six treatments: (T₁) RDF, (T₂) RDF + seed inoculation of sulphur oxidizing bacteria (T. thiooxidants), (T₃) RDF + 5 kg humic acid ha^-1 + seed inoculation of sulphur oxidizing bacteria (T. thiooxidants), (T₄) RDF + 10 kg humic acid ha^-1 + seed inoculation of sulphur oxidizing bacteria (T. thiooxidants), (T₅) RDF + 15 kg humic acid ha^-1 + seed inoculation of sulphur oxidizing bacteria (T. thiooxidants) and (T₆) 75% RDF + 15 kg humic acid ha^-1 + seed inoculation of sulphur oxidizing bacteria (T. thiooxidants) with four replications. The results indicated that the treatment (T₅) RDF + 15 kg humic acid ha^-1 + seed inoculation of sulphur oxidizing bacteria T. thiooxidants recorded the highest plant height at harvest (201.56 cm), ear head diameter at harvest (18.94 cm), leaf area plant^-1 (29.57 dm²), dry matter accumulation (136.71 g plant⁻¹), number of seeds ear head^-1 (1254.1) and seed yield (2119.5 kg ha⁻¹).