Micro-sprinkling irrigation improves grain yield, dry matter accumulation and nitrogen use efficiency of purple wheat in the North China Plain

Background and Aims Micro-sprinkling irrigation (MSI) has been instrumental in enhancing crop yield and water utilization efficiency. Nevertheless, there is a paucity of research on the impact of MSI on purple wheat. Methods A field experiment was carried out to examine the influence of conventional irrigation practice (CI) and MSI on grain yield, dry matter accumulation, and nitrogen (N) use efficiency of purple wheat. Results The findings indicate that grain yield, protein yield, spikes per square meter and grains per spike increased by an average of 12.0%, 9.7%, 8.3%, and 8.7%, respectively, under MSI relative to CI. Additionally, the dry matter accumulation of MSI at various growth stages surpassed that of CI. MSI also led to an increase in leaf area index, specific leaf nitrogen and leaf area duration, while simultaneously decreasing specific leaf area. The net assimilation rate,N accumulation and productivity demonstrated similar patterns to leaf area duration during the stages from sowing to jointing and from anthesis to maturity. The improvement of N use efficiency resulting from MSI was primarily attributed to the increase in N uptake efficiency. Conversely, the lack of variation in N utilization efficiency was primarily due to the unchanged nitrogen harvest index and grain nitrogen concentration. MSI has increased the contribution of dry matter and nitrogen after anthesis to grains, while the reverse was true before anthesis. Conclusions As a result, MSI has been shown to enhance the growth and yield of purple wheat through improved dry matter accumulation and N use efficiency.