Fertilization, seeding date, and seeding rate for malting barley yield and quality in southern Alberta

Abstract

Weather conditions are often unfavourable for malting barley quality in southern Alberta, but agronomic practice may improve the probability of attaining acceptable quality. The objective of this study was to determine optimum agronomic practice (cultivar, fertilization, seeding date and seeding rate) for yield and quality of malting barley in southern Alberta. Field trials were conducted at 12 dryland sites and 2 irrigated sites over a 3-yr period (2001–2003). At each site, five experiments were conducted with the following treatments: (1) N rate (0, 40, 80, 120, and 160 kg N ha-1), (2) P rate (0, 6.5, 13 and 19.5 kg P ha-1), (3) K rate (0, 25 and 50 kg K ha-1), (4) S rate (0, 10, and 20 kg S ha-1), and (5) seeding date (three dates at 10-d intervals) and seeding rate (150, 200, 250, 300, and 350 viable seeds m-1). Seven cultivars were included in the first experiment and two cultivars were included in the remainder of the experiments. Maximum grain yields were achieved when fertilizer + available soil N (estimated from unfertilized grain N yield) exceeded 31 kg N Mg-1 maximum grain yield, whereas protein concentrations were usually acceptable if fertilizer + available soil N was between 25 and 40 kg N Mg-1 maximum grain yield. Higher N rates generally reduced kernel size. Cultivar differences in N response were negligible. Application of P, K, or S did not affect malt yield or quality. Seeding delays of ≈ 20 d reduced grain yields by an average of 20%, with relatively greater yield declines under drought stressed conditions. Delayed seeding did not affect or slightly increased grain protein concentration. Kernel size was both increased and decreased by delayed seeding. Increased seeding rates from 150 to 350 viable seeds m-2 generally provided small yield gains, slight reductions in grain protein concentration and reduced kernel size. The most beneficial agronomic practices for malt barley production in southern Alberta were early seeding and application of N fertilizer at rates appropriate to the expected availability of moisture and soil N. Key words: Hordeum vulgare, nitrogen fertilizer, phosphorus, potassium, sulphur, protein, plump kernels