Irrigated spring hull‐less food barley response to nitrogen fertilization

Abstract Barley ( Hordeum vulgare L.) is used mainly for malting, brewing, and animal feed. In antiquity, barley was a major calorie source for humans and has recently become of increased interest as consumers seek healthier options. Hull‐less barley plays a key role in this resurgence as the need to process barley through pearling is removed and modern cultivars have high fiber content. To our knowledge, no work has established fertilizer‐nitrogen (N) recommendations for hull‐less food barley under high‐yielding irrigated conditions common in the semi‐arid western United States. Research was conducted in the major irrigated production area of southern Idaho over 11 site‐years of replicated N response trial data (∼5 fertilizer‐N rates) from 2019 to 2023 for the cultivars Goldenhart and Julie. N‐supply is reported and is the sum of applied fertilizer‐N and soil inorganic‐N to 60 cm. Analysis of variance (ANOVA) critical N‐supply (CNS) was calculated site‐by‐site as the lowest yield that did not differ from the maximum. The average ANOVA CNS was 194 kg N ha −1 across all site‐years. A yield‐based approach and corresponding nitrogen requirements (Nr) from the ANOVA CNS resulted in an N‐supply range from 200 to 224 kg N ha −1 . A 95% relative grain yield (RGY) was used for linear‐ and quadratic‐plateau models which determined CNS of 194 and 234 kg N ha −1 , respectively. Protein increased slightly but was poorly explained by N‐supply. A static‐N range from 194 to 234 kg N ha −1 is suitable for irrigated hull‐less barley production.