Brasil
The biomass of oat (Avena sativa L.) production can be estimated by area, by plant and duration. This work was carried out at the Centro Agropecuário da Palma - CAP/UFPel in Capão do Leão/RS Brazil. A completely randomized block design was used with 9 replications. The evaluated populations were 100, 200, 300 and 400 plants m-2 with the modern cultivar UPF 18. In each experimental unit, the parameters evaluated were biomass (Kg ha-1 and g plant-1) of shoot (leaf, culm and chaff), biomass duration (Kg.day), plant height (cm), grain yield (Kg ha-1) and harvest index (%). Plant density did not influence grain yield, however other parameters such as biomass (Kg ha-1 and g pl-1), biomass duration and harvest index, were affected. Key words: biomass, oat, plant population, intraespecific, interaction