Plant canopy measuring instruments can be widely used in agricultural production and agricultural scientific research. In order to investigate canopy light energy resources, measure light interception in plant canopies, and study the relationship between crop growth and development, yield quality, and light energy utilization, this instrument The instrument is used to measure and record photosynthetically active radiation (PAR) in the 400nm-700nm band. The unit of measurement value is micromoles per square meter per second (μmol㎡/second).