Optimizing growth: The role of plant density and nitrogen fertilization on dual-purpose yellow sorghum (PYPS-2)

A study was conducted at College Farm, College of Agriculture, Rajendranagar, Hyderabad during Kharif 2023 to examine the impact of plant density and nitrogen levels on the growth and development of yellow sorghum, focusing on plant height, leaf area, leaf to stem ratio, and dry matter accumulation. The study was plotted in split-plot design with plant densities (D1: 222222 plants ha-1 (30cm x 15cm), D2: 148148 plants ha-1 (45cm x 15cm) and D3: 111111 plants ha-1 (60cm x 15cm)) in the main plots and nitrogen levels (N0: 0 kg N ha-1, N1: 30 kg N ha-1, N2: 60 kg N ha-1 and N3: 90 kg N ha-1) in the sub plots and replicated thrice. The result indicated that higher plant density (D1: 222,222 plants ha⁻¹) and nitrogen application (N3: 90 kg N ha⁻¹) significantly increased plant height at all stages. Lower densities (D3: 111,111 plants ha⁻¹) led to greater leaf areas and leaf to stem ratios while higher densities (D1: 222,222 plants ha⁻¹) resulted in smaller leaf areas and leaf to stem ratios. Nitrogen application at 90 kg ha⁻¹ significantly enhanced leaf development with larger leaf area and leaf to stem ratios, while no nitrogen (0 kg ha-1) resulted in the smallest leaf areas and leaf to stem ratios. Dry matter production increased steadily, with the most accumulation occurring before 50% flowering. The plant density D2 (148,148 plants ha⁻¹) produced the highest dry matter at harvest (16,336 kg ha⁻¹), and the highest nitrogen level (N3) further increased this to 19,285 kg ha⁻¹. No significant interaction was observed between plant density and nitrogen levels for any measured traits.