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We investigated the effects of nitrogen top-dressing on yield, grain quality and grain protein content of wheat cultivar 'Satonosora' in an upland field converted from a paddy field in Chiba Prefecture. 1. Top-dressing with 40 kgN/ha, from panicle initiation to the jointing stage, significantly increased yield. 2. Top-dressing with 40 kgN/ha at heading significantly increased grain nitrogen content, but resulted in lower grain quality. 3. Increasing the amount of nitrogen fertilizer by top-dressing in the range of 60 kgN/ha from 20 kgN/ha tended to increase yield and grain protein content. 4. Increasing grain nitrogen content tended to lower the grain's quality and class. 5. Two top-dressings, comprising 40 kgN/ha from panicle initiation to the jointing stage and 40 kgN/ha at heading, due to sufficient sunshine and average precipitation conditions during the ripening period increased yield, maintaining high grain quality and a high class of grain nitrogen content.
