ABSTRACT

The self-sufficiency ratio and national average yield of wheat are low in Japan. Reducing the yield gap and receiving the government subsidy for grain quality are vital strategies for profitability. Elucidating optimum nitrogen application scheme is awaited to attain both higher yield and appropriate grain protein content (GPC) for wheat cultivation in Japan. Such decision support can be realized by integrating field experimental knowledge to crop growth models, although they have scarcely been utilized for wheat production in Japan. Therefore, the purposes of this study were to apply a widely used crop growth model (APSIM) to wheat growth on an Andosol in the Kanto region in Japan by calibration and validation. Selected model parameters of APSIM-wheat for phenology, leaf growth, and grain formation were readjusted based on the phenology and growth data of soft and hard wheat cultivars. Then the model was validated by using similar variables obtained in an independent experiment. For the simulation of the optimum sowing for winter wheat in the Kanto area (November), the root mean square error for grain yield was 23 and 48 g m⁻² for Ayahikari and Yumeshiho varieties, respectively, and that for GPC was 1.9 and 1.4%. Thus, the overall model performance was acceptable for optimum sowing. However, grain yield and dry matter production were significantly overestimated when the data of late sowing groups were included. Therefore, further model improvement was suggested to add an algorithm to reduce the number of emerged plants under cold temperature in late sowing conditions.

摘要

日本小麦的自给率和全国平均产量较低。缩小产量差距和获得政府对粮食质量的补贴是盈利的重要策略。正在等待阐明最佳施氮方案，以在日本小麦种植中获得更高的产量和适当的谷物蛋白质含量 (GPC)。这种决策支持可以通过将田间试验知识与作物生长模型相结合来实现，尽管它们在日本几乎没有用于小麦生产。因此，本研究的目的是通过校准和验证，将广泛使用的作物生长模型 (APSIM) 应用于日本关东地区 Andosol 上的小麦生长。用于物候学、叶生长、根据软、硬小麦品种的物候和生长数据重新调整籽粒形成。然后通过使用在独立实验中获得的类似变量来验证模型。关东地区冬小麦最佳播种模拟（11 月），粮食产量均方根误差分别为 23 和 48 gmAyahikari 和 Yumeshiho 品种分别为^-2，GPC 为 1.9 和 1.4%。因此，整体模型性能对于最佳播种是可以接受的。然而，当包括晚播组的数据时，谷物产量和干物质产量被显着高估。因此，建议进一步改进模型，增加一种算法，以减少晚播条件下低温下出苗的数量。