Spring Malt Barley Grain Yield and Quality As Affected By Nitrogen Rate and Final Irrigation Timing.

High yielding and quality malt barley (hordeum vulgare L.) is critical for producing malt and beer. Research trials investigating the impact of final irrigation timing cutoffs [i.e., late boot, soft dough, and soft dough + 7 days (SD7)] and nitrogen (N) rates (0 to 150 lb N/ac) at the Kimberly Research and Extension were conducted during the 2015 growing season. The study measured yield and quality factors as well as N uptake and partitioning and soil nitrate and moisture levels during the course of the study. Cutoff at the boot stage severely stressed plants as soil moisture was insufficient to finish out the crop reducing yield, protein, and plumps to unacceptable levels, indicating the need for proper irrigation. Scheduling the final irrigation for soft dough, where the soil profile was full, resulted in a nearly 20% reduction in water usage where no reductions in yield or quality occurred at optimal N rates. This is a key factor as water curtailments are proposed for Idaho and properly timed irrigation will ensure high yields/quality and minimal lodging while reducing the total water usage of the crop. Additionally, results indicated that excessive N applications are unlikely to increase yield goals and thus, proper N applications will ensure adequate N for the plant that reduces the potential for negative agronomic and environmental effects Under the current study conditions, results indicate barley is likely to reduce or retain soil nitrate levels when nitrogen applications are made at appropriate N rates. By optimizing the nitrogen and water provided to the crop, barley growers can ensure they are only using the amount of water and fertilizer resources needed to maximize returns while maintaining quality specifications.