PROBLEM TO BE SOLVED: To make it possible to determine an appropriate fertilization amount by a new method in consideration of an influence of an element found to affect a state of a harvested product due to cultivation of an agricultural crop. A fertilizer application rate determination device (1) obtains information about vegetation during topdressing and expected temperature information indicating an expected temperature during a ripening period or a growing season, and also applies past fertilization amount during actual topdressing and at the time of topdressing. Information about vegetation, temperature during the ripening or growing season that has arrived after topdressing, and information that is generated based on the state of crops that have been harvested after the ripening or after the growing season. Is a predetermined state, and when the temperature during the ripening period or the growing season is expected to be a predetermined temperature, the amount of fertilizer required at the time of additional fertilization to bring the state of the harvested crop to the target state. Fertilization rate related information is acquired and the fertilization rate is determined based on each information, so that the fertilization rate can be determined by reflecting the information on vegetation during topdressing and the expected temperature during the ripening period or the growing season. I have to. [Selection diagram] Figure 1【課題】農作物の栽培による収穫物の状態に影響することが判明した要素による影響を考慮した新たな手法で適切な施肥量を決定できるようにする。【解決手段】施肥量決定装置１は、追肥時の植生に関する情報および登熟期または生育期の予想気温を示す予想気温情報を取得すると共に、過去の実際の追肥時の施肥量、追肥時の植生に関する情報、追肥後に到来した登熟期または生育期の気温、および、登熟期後または生育期後に収穫された農作物の状態に基づいて生成された情報であって、追肥時の植生に関する情報が所定の状態であり、かつ、登熟期または生育期の気温が所定温度であると予想される場合に、収穫される前記農作物の状態を目標の状態とするために追肥時に必要な施肥量に関する施肥量関連情報を取得し、各情報に基づいて施肥量を決定することにより、追肥時の植生に関する情報と登熟期または生育期の予想温度とを反映して、施肥量を決定するようにしている。【選択図】図１
