Improving the efficiency of milling oat (Avena sativa L.) production is becoming increasingly important under rising input costs and variable climatic conditions. However, oat agronomy research remains underfunded, leading to knowledge gaps in optimizing yield and quality in commercially relevant varieties. The aim of this work was to investigate the effects of seed rate and nitrogen (N) rates on commercial oat varieties across multiple environments in the UK and Canada over three growing seasons. Increasing seed rates reduced plant establishment rate, particularly under favorable growing conditions, while reducing seed rates maintained comparable yields through compensatory increases in plant productivity. A seed rate of 200 seeds m−2 improved establishment efficiency and reduced seed rate costs. N response was strongly influenced by environmental conditions and background soil N. In Fort Whyte, Manitoba, Canada, high residual soil N and a shorter growing season limited the benefit of additional fertilizer beyond 40 kg N ha−1, while site-specific N management in Nipawin, Saskatchewan, Canada, improved both yield and grain quality with minimal adverse effects on grain weight. In Scotland, UK, higher N rates increased lodging risk, although lodging-tolerant varieties such as Conway achieved improved yield responses under moderate additional N inputs. Overall, the findings demonstrate that oat yield and quality responses are highly site- and variety-specific. Optimizing oat production, therefore, requires locally tailored management strategies integrating seed rates, fertilizer, environmental conditions and varietal choices to maximize productivity, quality and input efficiency.
Bright et al. (Tue,) studied this question.