A measuring system for estimating the frequency distribution of irradiance within plant canopies.
A measuring system for estimating the frequency distribution of irradiance within a plant stand is described. The system uses a distributed set of 32 sensors to measure temporal and spatial variations in irradiance in a canopy. It is constructed to fulfil the requirement for instantaneous values of irradiance in small space units in studies of photosynthetic production. The temporal and spatial averaging of irradiance in the measuring procedure is minimized through the use of small light sensors which match the time constant of photosynthesis and the variability of the radiant flux in the plant canopy. The processing of the data is described and its application in photosynthetic studies is discussed.