Stand structure and light penetration. 4. A sensor for measuring photosynthetically active radiation. Published online01 Jan 1981Content typeJournal articleJournal titleJournal of Applied EcologyDOI10.2307/2402973 Author(s)Fitter, D. J. & Knapp, P. H. & Wilson, J. W. Publication languageEnglishLocationUK View AbstractThe construction and calibration of a sensor for measuring light interception in crop canopies are described.Key wordsapparatuscanopyequipmentleaveslight penetrationView