Abstract
Winter wheat usually seeded in autumn was seeded before continuous snow cover and the most appropriate method of nitrogen (N) fertilization was examined using variety “Nanbukomugi”. In the plants supplied with N fertilizer at seeding time, the growth increment at maturity and yield were higher than in those supplied with N just after the snow melted. The yield increased with increasing amount of N fertilizer applied. In the plants seeded before continuous snow cover and supplied with 10 gN/m2 at seeding time, the yield was the same as or higher than that in the plants seeded in autumn. This is probably because early growth was promoted by a sufficient amount of N which was released from the fertilizer applied at seeding time. The protein content of the grains was 11 % or more when N fertilizer was supplied at seeding time, and it increased with increasing amount of N applied. In the plants supplied with N fertilizer at seeding time, the appearance quality of the grains was better, and the lodging degree was lower than those in the plants supplied with N fertilizer just after the snow melted. From these results, we recommend the application of N fertilizer at seeding time at 8-10 gN/m2 to increase the yield.
