Seid, Kedija AhmedJibat, Diribi MijenaDamtew, Habtamu Alebachew2026-06-082026-06-082026-05-112784-0379https://repository.iuls.ro/handle/20.500.12811/6537A study was conducted from 2019 to 2021 at the Assosa Agricultural Research Center to evaluate the effects of nitrogen (N) fertiliser application and cleaning cut timing on the seed yield and quality of Andropogon gayanus. The experiment used a split-plot design in a randomised complete block arrangement with four replications. Four N levels [0(control), 23, 46, and 69 kg ha−1] were assigned to the main plots, and four cleaning cut timings (15, 30, 45, and 60 days after rainfall onset) were assigned to the subplots. Analysis of variance showed significant (p < 0.05) effects of N rate, cleaning cut interval, and their interaction on seed yield and most yieldrelated traits. The highest inflorescence density (147.38 m−²) was recorded at 69 kg ha−1 N, and the 15-day cut produced the most racemes per inflorescence (6.91). The maximum seed yield (675.05–722.03 kg ha−1) and optimal seed germination (>68%) were attained when N rates of 23–69 kg ha−1 were combined with a cleaning cut at 30–45 days. Based on the seed yield and quality, applying 23–69 kg ha−1 N with a 30–45-day cleaning cut is recommended to optimise seed production for A. gayanus in the study area and similar agroecologies. Future research should expand on these findings by evaluating economic cost–benefit analyses, alternative N sources, such as biofertilisers, and the long-term storage potential of seeds through germination tests seven months after harvest.EnglishAttribution 4.0 International (CC BY 4.0)http://creativecommons.org/licenses/by/4.0Andropogon gayanuscleaning cut timingforage grassnitrogen fertilisationseed germinationseed yieldArticle2784-0360https://doi.org/10.46909/alse-591202