Effect of planting geometry and nitrogen levels on fodder quality of multicut sorghum

Abstract:

Livestock productivity in the East African highlands hinges on a reliable supply of protein-rich green fodder year-round. Multicut sorghum (Sorghum bicolor (L.) Moench) is one of the few warm-season grasses that can deliver three to four harvests in a single growing season, yet its fodder quality response to spatial arrangement and nitrogen management under highland conditions remains poorly documented. A field experiment was laid out in a split-plot design with three planting geometries (G1: 30 × 10 cm, G2: 45 × 15 cm, G3: 60 × 20 cm) as main plots and five nitrogen levels (0, 40, 80, 120, 160 kg N/ha) as subplots, replicated three times, at the Haramaya University, Dire Dawa, Ethiopia, during the Meher season of 2023. Crude protein, Neutral Detergent Fibre (NDF), Acid Detergent Fibre (ADF), and total ash were determined in leaf and stem fractions at each of three cuts. Nitrogen at 120 kg/ha produced the highest crude protein (10.9%) without a significant further rise at 160 kg/ha. Wider geometry (G3) yielded individual plants with 14.7% more leaf proportion than G1, improving the leaf-to-stem ratio and reducing NDF by 3.2 percentage points. The G2 × 120 N combination offered the best trade-off between fodder quality and total dry matter yield per hectare.