Barley yield and malt characteristics as affected by nitrogen and final irrigation timing

Abstract

Idaho is a major malt barley (Hordeum vulgare L.) producer in the United States. Production is concentrated in the semi‐arid Snake River Plain region of southern Idaho. Irrigation and fertilizer N applications are two of the most important managed factors. Research was conducted at the University of Idaho Kimberly Research & Extension Center near Kimberly, ID, to determine yield, grain quality, and malt characteristics as affected by N application rate (0, 56, 112, and 168 kg N ha−1) and final irrigation timing at Feekes 10.0 (boot; F10.0), Feekes 11.2 (soft dough; F11.2), and +7 d after Feekes 11.2 (+7F11.2). Irrigation termination at F10.0 resulted in decreased yields and unacceptable malt characteristics across N rates. Irrigation termination at F11.2 and +7F11.2 yielded 6,439 kg ha−1 at a fertilizer N application of 56 kg N ha−1, similar to higher N applications. Greater predicted yields up to 6,886 kg ha−1 were calculated by regression analysis with applications up to 147 kg N ha−1. Grain yield, protein, plumps, and test weights did not differ at any N rate for F11.2 or +7F11.2. Malt extract, free amino N, and diastatic power were similar for the F11.2 and +7F11.2 irrigations. Malt β‐glucan content did not differ up to 56 kg N ha−1 for any treatment, but reductions of up to 30 mg kg−1 were measured at higher N rates for the +7F11.2 irrigation. Results warrant further investigations into increased N applications and provide evidence of the effects of irrigation cutoff timing and N for malt barley.

Deficit irrigation effects on adjunct and all‐malt barley yield and quality

“…However, barley production in the semiarid west is concentrated in high‐value malting barley, where yields are typically large and strict quality specifications must be met. Research has shown that barley grain quality can be decreased, particularly when the water deficit occurs during grain formation (Carter & Stoker, 1985; Qureshi & Neibling, 2009; Rogers et al., 2022). Of major interest to the end‐product of malt and beer production is the end protein levels that are critical for the malting process.…”

“…DP increased and was within the acceptable target for adjunct brewing at all irrigation levels but was only within the target range at 100% ET c for all‐malt brewing. Free amino N is generally considered to increase with greater overall grain protein content (Luo et al., 2019; Rogers et al., 2022). However, despite an increase in grain protein/N with decreased irrigation, no irrigation effect was measured from FAN and only genotype differences were measured.…”

“…In small‐grain cereal crops specifically, crop water stress early in crop development and around anthesis can reduce yield through a reduction in number of kernels per area and mean weight of kernels (Calderini et al., 2001; Carter & Stoker, 1985; Fischer, 1985; Pardo et al., 2022; Savin & Slafer, 1991). Grain quality parameters can be negatively impacted under water‐stressed conditions particularly when stress occurs during grain fill (Qureshi & Neibling, 2009; Rogers et al., 2022; Stevens et al., 2015). Protein content is particularly susceptible to negative effects as water stress results in less N dilution in the grain due to yield accumulation, and thus, increased protein that is detrimental to malting (Jahromi et al., 2022; Rogers et al., 2022; Stevens et al., 2015; Walsh et al., 2020).…”

“…Grain quality parameters can be negatively impacted under water‐stressed conditions particularly when stress occurs during grain fill (Qureshi & Neibling, 2009; Rogers et al., 2022; Stevens et al., 2015). Protein content is particularly susceptible to negative effects as water stress results in less N dilution in the grain due to yield accumulation, and thus, increased protein that is detrimental to malting (Jahromi et al., 2022; Rogers et al., 2022; Stevens et al., 2015; Walsh et al., 2020). Additionally, genotype variation in grain protein under full and water‐stressed conditions has been measured (Liang et al., 2022).…”

Malt Barley Yield and Quality Response to Nitrogen and Irrigation Termination Timing

“…Termination of irrigation at Feekes 10.0 is considered water stressed, and termination of irrigation at F11.2 and +77F11.2 is considered well watered. Water‐stressed conditions in the F10.0 treatment resulted in a more than 30% reduction in grain yields, and N fertilizer provided little benefit to a net negative effect under water‐stressed conditions (Figure 1; Rogers et al, 2022). Maximum yield in the study occurred well below the maximum rates of fertilizer N applications for both F11.2 and +7F11.2, which did not differ.…”