Abstract: The present invention provides a photosynthesis rate measurement system capable of measuring carbon dioxide concentration in order to calculate the photosynthesis rate of plants with a simple configuration. The present invention is a photosynthesis rate measurement system, including a covering portion covering target plants, a sensor housing, and a sensor alternately measuring carbon dioxide concentrations inside and outside the covering portion. The sensor is provided in the sensor housing, and an air stirring portion to improve the sensor's response is equipped in the sensor housing.

Abstract: This invention provides a plant health diagnostic method and a plant health diagnostic device for detecting initial disorder of a plant individual body carrying pests or the like in a large-scale plant cultivation field. The plant health diagnostic method is for diagnosing a health state of a plant in accordance with chlorophyll fluorescence emitted from chlorophyll of a plant body. The method includes: obtaining a first minimum point s after a maximum point p having largest chlorophyll fluorescence intensity and a first maximum point m after the minimum point s on a time course curve for the chlorophyll fluorescence intensity; defining chlorophyll fluorescence intensity values at the minimum point s and the first maximum point m after the minimum point s as S and M, respectively; and comparing the value S and the value M to evaluate the state of the plant.

Abstract: This invention provides a plant health diagnostic method and a plant health diagnostic device for detecting initial disorder of a plant individual body carrying pests or the like in a large-scale plant cultivation field. The plant health diagnostic method is for diagnosing a health state of a plant in accordance with chlorophyll fluorescence emitted from chlorophyll of a plant body. The method includes: obtaining a first minimum point s after a maximum point p having largest chlorophyll fluorescence intensity and a first maximum point m after the minimum point s on a time course curve for the chlorophyll fluorescence intensity; defining chlorophyll fluorescence intensity values at the minimum point s and the first maximum point m after the minimum point s as S and M, respectively; and comparing the value S and the value M to evaluate the state of the plant.