Balancing economic and environmental goals in winter barley: the role of nitrogen timing and genotypes

Abstract

Despite a relatively high share of cropping area in northern European agriculture, little is known about how nitrogen (N) fertilization in autumn and spring affects winter barley grain yield and the mechanisms involved. Based on a field trial from 2016 to 2024, the study examined the effect of eight N treatments (two autumn and four spring N levels) and two winter barley genotypes (hybrid vs. line), focusing on green area index (GAI), photosynthetically active radiation (PAR) interception, grain yield and N balance. Results suggest that yield increases from N fertilization were due to higher PAR interception, which boosted grain numbers per square meter. However, the effect of autumn N was minimal when spring N fertilization was sufficient. Although hybrids intercepted less PAR than lines, they used it more efficiently, consistently yielding more. To optimize yield and N use efficiency, we recommend using hybrid genotypes with spring-only N fertilization. Autumn N fertilization leads to higher N balances, making it unsuitable for meeting European environmental goals.