Nitrogen Fertilizer Application and Seeding Date Effects on Oat Grain Milling Quality

Management factors such as N fertilizer rate and seeding date can significantly influence oat ( Avena sativa L.) grain milling quality. The effects of N fertilizer and seeding date on the grain yield and milling quality of four oat cultivars were evaluated using two N rates (40 kg ha −1 applied at seeding or 40 kg ha −1 applied at seeding plus 20 kg ha −1 applied at the boot stage) and two seeding dates. Studies were conducted at Ste‐Anne‐de‐Bellevue, PQ, Canada, from 1990 to 1992 and at Ste‐Rosalie, PQ, in 1991. Nitrogen treatments had little effect on milling quality at Ste‐Anne‐de‐Bellevue, but hull percentage decreased and plump grain percentage increased with higher N in the Ste‐Rosalie experiment. Delayed seeding reduced yields in all four experiments. In the Ste‐Anne‐de‐Bellevue experiments, delayed seeding reduced test weight, 1000‐grain weight, plump grain percentage, and theoretical milling yield and increased percentage of hull, thin grain, and bosom grain. In the Ste‐Rosalie experiment, opposite effects were observed; this may have resulted from reduced production of secondary and tertiary seeds in the late‐seeded treatments. For most milling quality characteristics, significant differences between cultivars were observed, and cultivars interacted with management treatments. In general, the higher application rate of N did not improve oat grain milling quality sufficiently to warrant its usage. Later seeding resulted in inferior yields at all locations, but did not necessarily reduce milling quality. The correct choice of cultivar seems crucial for production of high‐quality milling oat grain.