PROBLEM TO BE SOLVED: To provide a method for determining the growth stage of a plant, which enables accurate determination of the growth stage of a plant.SOLUTION: The method for determining the growth stage of a plant includes setting scattering-light sensors 1 each composed of a black light-shielding frame 2 where only one vertical surface of a cubic box body is made open, and a silicon photodiode 3 set up inside the light-shielding frame 2 in a posture of making a light-receiving surface face to the opening of the light-shielding frame 2, at two portions on the inside of a plant group P and the outside of the plant group P respectively, in a state where the respective receiving surfaces face to the north direction, measuring an output difference &DeltaP of both of the scattering light sensors 1, 1 with a measurement means 7 so as to determine the growth stage of the plant based on the measurement result.COPYRIGHT: (C)2009,JPO&INPIT【課題】植物の生育段階を正確に判定可能とする。【解決手段】立方体状の箱体の鉛直方向の一面のみを開口させた黒色の遮光枠2と、その遮光枠2内に、受光面を遮光枠2の開口に向けた姿勢で設置されるシリコンフォトダイオード3とからなる散乱光センサ1を、植物群落P内と植物群落P外との二箇所に、夫々受光面を北方向に向けた状態で1つずつ設置して、測定手段7で両散乱光センサ1,1の出力差ΔPを測定し、測定結果に基づいて植物の生育段階を判定するようにした。【選択図】図1
